Here is a list of the currently available Frequently Asked Questions (FAQs) for Agilent's consumable products in the Chemistries and Supplies Division (CSD) in the following categories:
Filaments and Ion Sources
Question Q002 What are the steps to troubleshoot a broken filament? Answer A002 Troubleshooting a broken filament: There is a dramatic change in the signal when a filament breaks. A typical result is a precipitous drop in the baseline during data acquisition. Also, the Chemstation will typically exhibit the NO EMISSION CURRENT error during tuning. All 5973A/N MSDs equipped with the EI source have 2 filaments. If one of the filaments breaks, you can use the Chemstation software to change to the alternate filament. After selecting the alternate filament, go to the Edit MS Parameters screen and proceed to the FILAMENT SELECT BOX, (which could have either FILAMENT 1 or 2 selected) and select the alternate filament. After selecting the alternate filament, try to execute a scan using the [Scan] button at bottom of screen. If the Scan is successful (meaning no errors occur), then exit the screen. This will put you back at the top level of MANUAL TUNE. At this point select [FILE], and then save the tune values to the tune file you are using. Question Q111 What information is included on the CofA? Answer A111 A Certificate of Analysis is shipped with each standard detailing the specific MW characteristics for each vial.
Gas Management
Question Q003 What filaments are supported on the MSD? Answer A003 https://www.agilent.com/cs/library/support/documents/F05003.pdf Question Q004 What is the procedure to maintain the MS Filaments? Answer A004 Maintaining MS Filaments: Like the filament in an incandescent light bulb, the ion source filaments will eventually burn out. Certain practices will reduce the chance of early failure: When setting up data acquisition parameters, set the solvent delay so that the analyzer will not turn on while the solvent peak is eluting. When the software prompts "Override solvent delay" at the beginning of a run always select No. Higher emission current will reduce filament life. If you are changing your MSD from the [Edit Parameters] screen, always select MS Off before changing any of the filament parameters. Question Q005 Are there any concerns about the temperature of the gas or the surroundings when using the Agilent G6691A Flowmeter?? Answer A005 The gas flow can be any temperature. The storage temperature for the Flow Meter will affect accuracy. The unit should be stored at temperatures under 50 degrees Celsius. A sticker is attached to each unit to gauge if the Flow Meter has gone outside the recommended temperature range while in storage or transit. If that happens, the sticker on the unit will turn black. The Flow Meter should then be sent back as a DEFOA and a replacement sent to the customer. Question Q006 Can I recycle my gas traps? Answer A006 Generally no, accept for Renewable Gas Purification Systems http://www.agilent.com/en-us/products/lab-supplies/chromatography-spectroscopy/gas-management/renewable-gas-purification-system Question Q007 Can I use rechargeable batteries in the Agilent G6691A Flowmeter? Answer A007 Yes, but the Flow Meter won’t read full battery power; cell voltage with the rechargeable batteries will be less than with alkaline batteries. Question Q008 Can it measure corrosive gases (e.g. ammonia)? Answer A008 No. This is not approved by Agilent. If measured, the warranty is invalidated and Agilent can’t guarantee the future performance or accuracy of the Flow Meter. The Flow Meter is designed for dry, noncorrosive gases. Question Q009 Can the Agilent G6691A Flowmeter measure corrosive gases (e.g. ammonia)? Answer A009 No. This is not approved by Agilent. If measured, the warranty is invalidated and Agilent can’t guarantee the future performance or accuracy of the Flow Meter. The Flow Meter is designed for dry, noncorrosive gases. Question Q010 Does the cartridge for the Agilent G6691A Flowmeter have a shelf life? Answer A010 The recommended shelf life is one year plus one additional year of use. The box it ships in has a temperature sticker stating if the cartridge is stored at a temperature above 130 F that could damage the components. Question Q011 Does the temperature of the gas affect the measurement on the Agilent G6691A Flowmeter? Answer A011 Yes. For a given mass flow rate the volumetric flow rate of a gas vary with the gas temperature and pressure. For a given mass flow rate the volumetric flow rate will increase with an increase in gas temperature and a decrease in gas pressure. As the ADM Flow Meter is a volumetric flow meter it will report the flow rate as it is measured. In mass flow mode the temperature and pressure are taken into account and the flow rate is displayed as if the gas temperature was 0 °C and 1 atm of pressure. Question Q012 How do I download the calibration certificate for the Agilent G6691A Flowmeter? Answer A012 Consult the Flow Meter Operating Instructions https://www.agilent.com/cs/library/usermanuals/public/G6691-90000.pdf Question Q013 How do I get a replacement hose for the Agilent G6691A Flowmeter? Answer A013 The part number for the replacement hose is G6692-68000. Question Q014 How do I know when to change my GasClean Filers? Answer A014 https://www.agilent.com/cs/library/usermanuals/public/5973-1528_GasCleanFilter_UserManual_EN.pdf Question Q015 How do I update the firmware on the Agilent G6691A Flowmeter? Answer A015 Consult the Flow Meter Operating Instructions https://www.agilent.com/cs/library/usermanuals/public/G6691-90000.pdf Question Q016 How many points are on the Certificate of Calibration for the Agilent G6691A Flowmeter? Answer A016 The unit is calibrated using 12 points and verified at 14 flow rates, which are show on the certificate. The verification points are: 0,0.5,1.0,5.0,10,50,100,300,400,500,601,700,750 ml/min. Question Q017 I have a Agilent G6691A Flowmeter. What do I do with the spare cartridge after it is out of calibration? Answer A017 The consumed cartridge can be disposed of per your local requirements for electronic waste. A new cartridge can be ordered online at https://www.agilent.com/en-us/products/lab-supplies/chromatography-spectroscopy/gas-management/adm-flow-meter#buy-products Question Q018 I have a Gas Clean filter, what does it mean if the indicator is changing colors from the bottom up? Top down? Answer A018 https://www.agilent.com/cs/library/usermanuals/public/5973-1528_GasCleanFilter_UserManual_EN.pdf Question Q019 If I cut the hose on the Agilent G6691A Flowmeter?, will that affect my measurements? Answer A019 Changing the hose length will affect your measurements. The Flow Meter is calibrated with the hose. Question Q020 Is it safe to measure hydrogen with the Agilent G6691A Flowmeter? Answer A020 Yes. Agilent advises to purge with an inert gas after measuring hydrogen. Question Q021 Is the calibration start date for the Agilent G6691A Flowmeter what is listed electronically inside the flowmeter or is it what is listed on the calibration certificate shipped with the flow module? How do we justify this with our auditors when they ask Answer A021 It is what is listed electronically inside of the flowmeter. The flow cell calibration is valid for one year after installation. If the customer is unable to follow this guideline due to their local procedures, they will need to replace the cartridge based on the calibration certificate date rather than the Agilent recommended date provided on the screen. Question Q022 Is there a user manual supplied with the Agilent G6691A Flowmeter? Answer A022 The only documentation provided with the flowmeter is the calibration certificate and the Quick Start Guide. The user manual can be found on the product page on www.Agilent.com Question Q023 Is there an AC Adapter for the Agilent G6691A Flowmeter? Answer A023 You can use the USB cable but will need to purchase the appropriate plug for the cord. The unit can be powered by the USB, but it will not recharge the batteries. Question Q024 Is there instructions on how a measurement is done for split ratio using the Agilent G6691A Flowmeter? Answer A024 We developed a detailed Troubleshooting Guide that details this measurement at https://www.agilent.com/cs/library/technicaloverviews/public/5991-7685EN.pdf Question Q025 Is there instructions on how a measurement is done for split ratio? Answer A025 We developed a detailed Troubleshooting Guide that details this measurement at https://www.agilent.com/cs/library/technicaloverviews/public/5991-7685EN.pdf Question Q026 My Flow Meter OLED screen reads “Error code X.” What does that mean? Answer A026 All error codes are listed in the Operation Manual for the Flow Meter. Question Q027 The Agilent G6691A Flowmeter is supposedly able to be powered by both batteries as well as through USB. Why doesn’t the USB cable come with a power adaptor? Answer A027 The USB adapter is intended for connecting to the PC for updating the firmware or accessing the digital version of the calibration certificate. The Flow Meter is powered by 3 AA batteries. The USB port can be used to continuously power the device, but it is not able to recharge the AA batteries. The USB-Power adapter is not required for the device and is not supplied. 3 AA batteries are supplied with the flowmeter. Question Q028 The Agilent G6691A Flowmeter OLED screen reads “Error code X.” What does that mean? Answer A028 All error codes are listed in the Operation Manual for the Flow Meter. Question Q029 The manual in softcopy states that the Agilent G6691A Flowmeter can communicate to our computer via a USB cable. Where is the driver to support the USB connection? Answer A029 See the ADM Flowmeter PC Connection Guide https://www.agilent.com/cs/library/usermanuals/public/Agilent%20ADM%20Flow%20Meter%20PC%20Connection%20User%20Guide.pdf Question Q030 There is a temperature sensitive sticker applied to the Agilent G6691A Flowmeter box. What is it for? Answer A030 The temperature sensitive sticker is intended for use during shipment. The Flowmeter is designed with the same operating and storage temperature limits as the GC. Question Q031 We activated the Agilent G6691A Flowmeter and inserted the new cartridge, but the display on the cartridge is showing a different time and date. Is this following USA timing? Answer A031 The Flow Meter is set on Coordinated Universal Time (UTC). The intent of the timer is to indicate one year of use from the installation dates rather than a specific start date. This satisfies the needs of many compliant departments worldwide. Question Q032 What are the part numbers for the Agilent G6691A Flowmeter? Answer A032 G6691A is the Flow Meter, which includes the first cartridge. G6692A is the replacement cartridge. Question Q033 What are the part numbers of the adaptors for the detectors for the Agilent G6691A Flowmeter? Answer A033 5190-9576 is the FID Adapter for Flow Meter 5190-9577 is the NPD Adapter for Flow Meter 5190-9578 is the TCD Adapter for Flow Meter Question Q034 What are the ranges of operating conditions for the Agilent G6691A Flowmeter? Answer A034 Flow Range: 0 to 750 ml/min Accuracy: 0-500ml/min +- 2% of reading or +- 0.2 ml/min whichever is greater, 501-750 ml/min +-3% of reading Operating temperature range: 0C to 45C Power: 3 AA batteries or USB power Question Q035 What do I do with the spare cartridge after it is out of calibration? Answer A035 The consumed cartridge can be disposed of per your local requirements for electronic waste. A new cartridge can be ordered online at https://www.agilent.com/en-us/products/lab-supplies/chromatography-spectroscopy/gas-management/adm-flow-meter#buy-products Question Q036 What gas line traps are recommended for the MSD's? Answer A036 The recommended traps for MSD are ... 5182-3467 (He/H2 combination 1/8in. fitting) 5182-3468 (He/H2 combination 1/4in. fitting) Question Q037 What gas traps are recommended for Agilent GC? Answer A037 The recommended traps for GC are: 5182-3425 (H2 1/8 in. fitting) 5182-3424 (H2 1/4in. fitting) 5182-3427 (He 1/8 in fitting) 5182-3426 (He 1/4 in fitting) 5182-3441 (Nitrogen 1/4 in. fitting) 5181-8870 (Hydrocarbon removal 1/8 in. fitting) 5181-8871 (Hydrocarbon removal 1/4 in. fitting)Additional information can be found in the 6890 Gas Chromatograph Site Prep and Installation manual. You may click on the link below to download this manual. https://www.agilent.com/cs/library/support/documents/a15283.pdf Question Q038 What happens if I cover the vents on top of the Agilent G6691A Flowmeter? Answer A038 If the vents are covered on top, the Flow Meter will not read accurately and the internal components may be damaged, requiring the cartridge to be replaced. Question Q039 What happens if the Agilent G6691A Flowmeter overflows? Answer A039 If this does occur, the Flow Meter will log the date and time of when that occurred. A replacement cartridge will need to be ordered for the Flow Meter. Question Q040 What indicates the need To change the gas purifiers? Answer A040 https://www.agilent.com/cs/library/support/documents/F03036.pdf Question Q041 What is the maximum flow rate for the Agilent G6691A Flowmeter? Answer A041 The limit is 900uL per minute. If the customer hears a crunching noise, the transducer has been broken and the cartridge needs to be replaced. Question Q042 When I purchase the Agilent G6691A Flowmeter does it come with a flow cartridge? Answer A042 Yes. The replacement cartridge is not needed at time of purchase unless an extra cartridge is wanted as a spare.
GC Columns
Question Q043 When we opened the box for the Agilent G6691A Flowmeter we noticed that the hose was not connected to the cartridge. The flowmeter is calibrated with the hose, so doesn’t it mean that the hose should already come pre-installed? Answer A043 The tubing used in calibration is identical to the tubing shipped separately in the box. A replacement part number is available if the tubing is damaged. The intent of this warning statement is to advise the customer against altering the tubing which will impact the calibration. Question Q044 After replacing the column, what does error "Vacuum Pump is Not Ready" indicate? Answer A044 Please perform the following checks.If the system cannot generate the vacuum correctly, it shuts down the diffusion pump or the turbo pump, and the foreline pump. This can be caused by the following conditions: On the diffusion pump MSD, the vacuum did not go below 300mTorr. On the turbo pump MSD, the turbo pump speed is reduced below 80% for seven minutes.The typical cause in these cases is a major air leak. The side plate (on the analyzer) did not make a tight seal. The vent valve was not closed fully. The ferrule for the column on the MSD interface was not tightened. These problems can cause the foreline pump to not remove air from the vacuum manifold.There is a risk of damage to the analyzer and pump if air is not removed.When turning on the power to the MSD, always press the side plate to ensure it is fully closed.If the unit still does not start, please contact the customer service center at Agilent. Question Q045 Can a Guard Column Be Utilized? Answer A045 A guard column can be used with the LTM system as a phaseless transfer line that is used in the oven to connect modules with the injector and detector. Typically about 2 ft of transfer line provides sufficient length for the oven door to be opened. The transfer line to the injector can be lengthened, if desired. Most typically, the transfer line within the oven is an intermediate polarity deactivated fused silica tubing of the same inner diameter as the analytical column. The phaseless transfer line connected to the injector can easily be cut back or replaced at low cost, with the added advantage that the length of the analytical column is not reduced in this process. The most common choice of guard column is the intermediate-polarity (IP) deactivated fused silica. One set is typically included with the LTM column module. Other types are available from Agilent. Question Q046 Can graphite/polyimide ferrules be used with Pre-swaging tool Answer A046 Can graphite/polyimide ferrules be pre-swaged with this tool? The Column Installation Pre-swaging tool for graphite ferrules is compatible with graphite/polyimide blend ferrules. However, graphite/polyimide ferrules loosen and slide when removed from the fitting. To use the pre-swaging tool to measure the column distance when using a blended ferrule, thread the column through an inlet septum before installing the column nut and ferrule. Once the column nut is tightened in the pre-swaging tool, slide the septum to the bottom of the nut to keep it in place when the nut is removed from the tool. Question Q047 Can I order the old column cage design? Answer A047 The old column design and EZ-Grip are now obsolete. It’s not possible to order columns on the old column cage design anymore. Question Q048 Can I order these improved columns using the current part number? Answer A048 https://www.agilent.com/en-us/support/gas-chromatography/gc-columns/capillary/order-my-column-with-improved-performance-using-current-pn Question Q049 Can modules be connected To each other? Answer A049 Modules are easily connected to each other or other pieces of chromatographic hardware. The use of fused silica transfer line to connect modules to injectors and detectors is also easily used to connect modules to each other, valves, splitters, and other devices. Modules in series have been used to manipulate the composite selectivity, selectively accumulate certain compounds on the first column for subsequent analysis on the second, selectively transfer compounds from one column to the next, and to modulate the transfer from one column to the next. Question Q050 Column Installation Pre-Swaging Tool - metal ferrules Answer A050 Which metal ferrules are compatible with the Column Installation Pre-Swaging Tool for metal ferrules? The fitting was designed to accommodate the UltiMetal Plus Flexible Metal ferrules, and original Siltite ferrules. Question Q051 Do I need a transfer line module for each column module? Answer A051 For a single column module system, a single transfer line of the matching size (3" or 5") will be required to interface the module to the oven door. For dual column module systems, two transfer lines of the appropriate size will be required. Each column module requires a matching transfer line while being operated. Please note that there is an older (pre-MACH) design that is not compatible with MACH modules. Question Q052 Do you have a GC Column Cross-Reference guide? Answer A052 If you are using another manufacturer s GC column and would like to upgrade to an Agilent J&W column, this GC column cross-reference guide will make your conversion easy. Each section of this guide lists, by phase selection, the suggested Agilent J&W upgrade from other GC manufacturers columns. This is not, however, a complete listing, but represents only the most frequently used columns. If you do not find the column you are currently using and would like to upgrade to an Agilent J&W column, contact our Technical Support staff or if you are located in North America call us at 1-800-227-9770. Click on the manufacturer below to find your Agilent J&W upgrade. Quadrex: https://www.chem.agilent.com/cag/cabu/qdrxcref.htm Restek: https://www.chem.agilent.com/cag/cabu/rstkcref.htm SGE: https://www.chem.agilent.com/cag/cabu/sgecref.htm Supelco: https://www.chem.agilent.com/cag/cabu/splcocref.htm Chrompack /Varian: https://www.chem.agilent.com/cag/cabu/crmpkcref.htm Please contact your local Agilent Technologies representative if you need more information. Question Q053 Do you have information on GC Column test standards? Answer A053 Please click here (https://www.agilent.com/en-us/products/gas-chromatography/gc-supplies/standards/j-w-gc-column-test-standards) to know about some of the Agilent J&W GC Column Test Standards. You can compare your column's performance to the test chromatogram shipped with your J&W column from Agilent. The column test standard contains components that test the column for resolution characteristics, efficiency, and inertness. The test mixes are supplied at a concentration of 250 ng/ L in 2 mL vials. Match the phase and column diameter in the chart mentioned to find the test mix for your column. Please contact your local Agilent Technologies representative if you need more information. Question Q054 Does the new design affect the column performance? Can I use the same method? Answer A054 Although a different cage design will be used for the columns, the production location, procedures and quality of these columns remain unchanged, maintaining their superior performance. The method you’re currently using doesn’t need to be change as the actual column is still the same. Question Q055 GC Column Cross-Reference guide Answer A055 If you are using another manufacturer s GC column and would like to upgrade to an Agilent J&W column, this GC column cross-reference guide will make your conversion easy. Each section of this guide lists, by phase selection, the suggested Agilent J&W upgrade from other GC manufacturers columns. This is not, however, a complete listing, but represents only the most frequently used columns. If you do not find the column you are currently using and would like to upgrade to an Agilent J&W column, contact our Technical Support staff or if you are located in North America call us at 1-800-227-9770. Click on the manufacturer below to find your Agilent J&W upgrade. Quadrex: https://www.chem.agilent.com/cag/cabu/qdrxcref.htm Restek: https://www.chem.agilent.com/cag/cabu/rstkcref.htm SGE: https://www.chem.agilent.com/cag/cabu/sgecref.htm Supelco: https://www.chem.agilent.com/cag/cabu/splcocref.htm Chrompack /Varian: https://www.chem.agilent.com/cag/cabu/crmpkcref.htm Please contact your local Agilent Technologies representative if you need more information. Question Q056 GC Column Test standards Answer A056 You can compare your column's performance to the test chromatogram shipped with your J&W column from Agilent. The column test standard contains components that test the column for resolution characteristics, efficiency, and inertness. The test mixes are supplied at a concentration of 250 ng/ L in 2 mL vials. Match the phase and column diameter in the chart mentioned to find the test mix for your column. Please contact your local Agilent Technologies representative if you need more information. Question Q057 How do column modules connect to transfer line modules, the oven, the injector and detector? Answer A057 Column modules connect directly to transfer line modules, and the transfer line modules attach to the LTM oven door through the slots provided in the door. These can be connected in any order. It is often convenient to attach a column module to a transfer line module on the table top before attaching the transfer line to the door. Other times it is more convenient to attach or exchange a column module leaving the transfer line attached to the door, especially if there are connections to the modules already in place in the oven. Once modules are attached to the door through one or more of the available slots, the sample pathway between the sample introduction device (e.g., split/splitless injector), the modules, and the detectors are completed with short lengths of fused silica transfer line. The modules terminate in chromatography unions which allow easy connection to transfer line without any tools. Question Q058 How do I select a Split/Splitless liner? Answer A058 https://www.agilent.com/en-us/support/gas-chromatography/kb005098 Question Q059 How many modules can be operate simultaneously with different temperature programs? Answer A059 Up to 4 column modules can be operated simultaneously with different temperature programs. The operation of multiple modules requires that a matching number of heater controllers are installed, as well as fan brackets and transfer line modules. A maximum of two of the 5-in. format modules can be installed, so the operation of 3 modules will require at least two of the modules to be 3-in. format, and the operation of 4 modules will require that all are of the 3-in. size. With more than two modules, attention must be given to the total power demand of the system. The 3" modules (required for installing more than 2 modules) consume less power, but the LTM system is limited to two power supplies and the applications must operate within the power provided by these two supplies. Question Q060 How much force is needed to pre-swage a ferrule? Answer A060 How much force is needed to pre-swage a ferrule? A very common mistake is over tightening fittings. When pre-swaging, you only want the ferrule to compress gently around the column tubing, just gripping it. Column “grip” may be tested by gently moving column back and forth until you feel slight resistance. Symptoms of over tightening (either with the Pre-swaging tool or the inlet fitting) are column breakage, ferrule flaking or deformation of the ferrule so that it extrudes into the opening of the fitting. Each of these have deleterious effects on your chromatography. Question Q061 How should customer condition a PLOT column before use? Answer A061 https://www.agilent.com/cs/library/usermanuals/public/I-0300%20PlotColumns_029627.pdf Question Q062 I just received 2 columns that look very different. What should I do? Answer A062 Due to the worldwide inventory of GC columns and the mix of products in our logistic centers, there is some chance you may receive columns wound on the current cage in the same shipment as columns using the standardized cage design. Please be aware the actual column and its performance is still the same. Question Q063 Since this is a replacement, why are the part numbers different for the improved columns? Answer A063 Having new part numbers ensures inventory of the standard and improved columns do not mix in our worldwide logistics centers. To receive the new improved columns, you will need to place an order using the new part numbers. Moving forward, these will be the only part numbers that will be available, as standard column part numbers will be obsoleted with depletion of their inventory. Go back to HP-INNOWax: https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary/hp-innowax#support and/or CP-Wax 52 CB: https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary/cp-wax-52-cb#support Question Q064 Spots on PLOT columns - will they affect the performance? Answer A064 No, they will not affect the column performance. See https://www.agilent.com/cs/library/support/documents/FAQ_Approved_PDF_PLOT_column_spots.pdf Question Q065 Spots on PLOT columns and will they affect the performance? Answer A065 No, they will not affect the column performance. See https://www.agilent.com/cs/library/support/documents/FAQ_Approved_PDF_PLOT_column_spots.pdf Question Q066 What about the QC test? Will this be different? Answer A066 In order to evaluate inertness performance, additional test probes have been added to the existing QC test mixtures. The specifications for all other parameters are unchanged. QC test probes play a key role in the adequate evaluation of column inertness and column-to-column consistency. Highly active analytes have been known to adsorb onto active sites of the column. Therefore, the composition and amount on-column of these probes must be carefully selected to allow sufficient detection of important column activity. An easy QC test mixture containing undemanding probes results in poor inertness evaluation because column activity may be insufficiently recognized. Testing columns using demanding test probes ensures consistent column inertness performance. This ultimately contributes to improvements in column-to-column consistency and reliability of analytical results. Question Q067 What are the possible causes for ghost peaks or carryover? Answer A067 Possible causes: • Contaminated carrier/makeup gas and delivery tubing • Contaminated solvent • Contaminated syringe (It is important to use sufficient solvent washes in auto injector to avoid cross contamination from sample to sample.) • Contaminated inlet liner/septum • Contaminated column • Contaminated detector plumbing and base weldment Possible solution: System contamination is responsible for most ghost peaks or carryover problems. If the extra ghost peaks are similar in width to the sample peaks (with similar retention times), the contaminants were most likely introduced into the column at the same time as the sample. The extra compounds may be present in the injector (i.e., contamination) or in the sample itself. Impurities in solvents, vials, caps and syringes are only some of the possible sources. Injecting sample and solvent blanks may help to find possible sources of the contaminants. If the ghost peaks are much broader than the sample peaks, the contaminants were most likely already in the column when the injection was made. These compounds were still in the column when a previous GC run was terminated. They elute during a later run and are often very broad. Sometimes numerous ghost peaks from multiple injections overlap and elute as a hump or blob. This often takes on the appearance of baseline drift or wander. Increasing the final temperature or time in the temperature program is one method to minimize or eliminate a ghost peak problem. Alternatively, a short bake-out after each run or series of runs may remove the highly retained compounds from the column before they cause a problem. Question Q068 What are the possible causes for peak tailing? Answer A068 There are different causes for peak tailing, some of possible causes are: Column Contamination Column activity Solvent-phase polarity mismatch Solvent effect violation for splitless or on-column injections Too low of a split ratio Poor column installation Some active compounds always tail Solution to above problems are as follows: 1. Column Contamination: -Trim the column (Remove 1/2-1 meter from the front of the column) -Solvent rinse the columns (Only for bonded and cross-linked phases) 2.Column activity: This is irreversible & it only affects active compounds 3. Solvent-phase polarity mismatch: -More tailing for the early eluting peaks or those closest to solvent front to resolve this change the sample solvent. -Install a 3-5 meter retention gap 4. Solvent effect violation for splitless or on-column injections: -Decrease the initial column temperature 5. Too low of a split ratio: -Increase the split ratio 6. Poor column installation: It results in more tailing for the early eluting peaks, reinstall the column. 7. Some active compounds always tail: Most common for amines and carboxylic acids always tail Question Q069 What are the possible causes of no peaks being observed? Answer A069 Check to see that the correct signal is assigned. You can assign not only detector outputs, but detector, injector and oven temperatures, as well as pressures to a signal. When you verify the signal assignment, check the signal level. You want some number greater than 0-1. This check is important especially for a TCD or FID, to ensure the wire is intact or the flame is lit. Check the column head pressure. If it is lower than expected, check for leaks. Question Q070 What are the Possible Causes of Peak Tailing? Answer A070 This could be a dirty injector or column, or a miss-cut column. Cool the injector down, turn off the flows, and replace or clean the injector parts, including the inlet liner and gold seal. Remove the column. Trim a length off the column to eliminate non- volatile residue, septum material and pieces of ferrule. This length may be from 1 inch to 1 meter or more as needed. Cut the column with a proper cutting tool. If the cut is poorly made, sample adsorption can occur. Consider scrubbing the steel inside walls of the injection port with a brass brush or mild abrasive such as aluminum oxide powder. Be sure to rinse the injection port well before re-installing any parts. Removing the split vent line and rinsing it with solvent is a good idea for your 5890 ( See the "How do I clean the split vent line on my 5890? question). When analyzing in the splitless mode, a too long splitless time can cause tailing. Common times are in the 0.5 to 1 minute range. Tailing can also occur due to unswept (dead) volumes. Verify the column is installed properly in the injector and detector. If losing a portion of the column is of concern, consider using an un-coated retention gap (pre-column) before the column. This can be cut or replaced without losing any column efficiency, and will lengthen the life of the column. Remember that the union between the retention gap and the analytical column is a source for leaks and sample adsorption. Question Q071 What are the possible causes of peaks being larger and eluting earlier? Answer A071 Faster, larger peaks are a result of less gas flow going out the split and septum purge vents and more going on the column; thereby increasing the head pressure and decreasing the split ratio. Check the flows out of the vents, and adjust if possible. If the problem persists, remove and clean the split vent. The problem could also indicate faulty flow controllers. Question Q072 What are the possible causes of peaks of interest showing up in blank runs? Answer A072 This can be a sample preparation or system cleanliness problem. Try new solvents, both the ones for sample and blank preparation, as well as the solvents in the sample wash bottles. Try a new syringe and septum. Remove and clean the split vent line. Make a run without any injection, to see if the peaks show up just by heating the column. Question Q073 What are the possible causes of resolution loss and retention time shift after installing a new column? Answer A073 Most likely a retention time shift is due to dimensional differences in the old and new columns. The previous column was likely trimmed during inlet maintenance and so the new column is likely longer than the old one. Also there is column-to-column variation due to dimensional tolerances range for diameter and length. The diameter of a column can be +/- 6 mm than the nominal diameter. The length can be up to 1 meter longer than the nominal length so that if a 30 meter column is ordered, it is guaranteed that 30m = column length = 31m. Usually these differences are too small to cause a problem. However, if the old and new columns happen to be at opposite extremes, the difference can be large enough to cause an issue. Here are some suggestions to minimize this effect: 1. If the GC has electronic pressure control (EPC), the best way is to enter the actual column diameter into the software. This actual measured value for the diameter is reported on the Performance Summary Sheet that came with the column. By inputting these values, the ECP will make adjustments to the flow to compensate for any differences in diameter. 2. If you ever trim the column you will want to report the new length to the software as well so that the EPC can compensate. The main lesson here is that flows and velocities are all mathematically derived based on the column dimensions input in the software. The only way to accurately set the velocity the same is to make a direct measurement using a non-retained analyte. For more information, please refer to the attached document. https://www.agilent.com/cs/library/support/documents/FAQ%20Approved%20PDF%20Template%20RT%20shift.pdf Question Q074 What are the Possible Causes of Resolution Loss and Retention Time Shift After Installing a New Column? - 5890 GC Answer A074 Most likely a retention time shift is due to dimensional differences in the old and new columns. The previous column was likely trimmed during inlet maintenance and so the new column is likely longer than the old one. Also there is column-to-column variation due to dimensional tolerances range for diameter and length. The diameter of a column can be +/- 6 mm than the nominal diameter. The length can be up to 1 meter longer than the nominal length so that if a 30 meter column is ordered, it is guaranteed that 30m = column length = 31m. Usually these differences are too small to cause a problem. However, if the old and new columns happen to be at opposite extremes, the difference can be large enough to cause an issue. Here are some suggestions to minimize this effect: 1. If the GC has electronic pressure control (EPC), the best way is to enter the actual column diameter into the software. This actual measured value for the diameter is reported on the Performance Summary Sheet that came with the column. By inputting these values, the ECP will make adjustments to the flow to compensate for any differences in diameter. 2. If you ever trim the column you will want to report the new length to the software as well so that the EPC can compensate. The main lesson here is that flows and velocities are all mathematically derived based on the column dimensions input in the software. The only way to accurately set the velocity the same is to make a direct measurement using a non-retained analyte. For more information, please refer to the attached document. https://www.agilent.com/cs/library/support/documents/FAQ%20Approved%20PDF%20Template%20RT%20shift.pdf Question Q075 What are the practical differences in the 3" (small) and 5" (standard) formats? Answer A075 Modules are available in 2 sizes: one contains 3-in. diameter (small) column assemblies, while the other contains 5-in. diameter (standard) column assemblies. The chromatography quality is basically equivalent for the two module sizes, so the 5-in. ("standard format") size is usually recommended for its faster cooling advantage. The same length of capillary column will have a greater surface area and reduced cross section in the 5-in. assembly compared to the 3-in. assembly resulting in faster cooling. The size of the cooling advantage can be estimated by comparing representative cooling data for typical LTM/GC systems. The 5-in. size does require the use of a horizontal pair of slots in the LTM system door compared to a single module of the 3-in. size. The stacking of two 5-in. modules can destabilize the temperature control precision for low temperature isothermal chromatography and is not recommended for stacked applications with starting temperatures below 40ºC. The 3-in. size is sometimes required in multiple module systems to allow room for other components. The 3-in. size is limited to maximum fused silica i.d. of 0.32mm, and the 5-in. size is required for large diameter fused silica columns such as 0.53mm i.d. The 5-in. size is also recommended for columns with delicate phases which should not be subjected to excessive curvature such as porous layer open tubular (PLOT) columns. Question Q076 What are the procedures for conditioning capillary GC columns? Answer A076 https://www.agilent.com/cs/library/datasheets/public/GCTroubleshooting_column_installation_notes.doc.pdf Question Q077 What are the steps to best troubleshoot column bleed? Answer A077 The best way to diagnose whether or not you are having a problem with column bleed is by generating a bleed profile when you first install a column under your method conditions, then comparing a bleed profile from a more recent run. If there is a substantial increase, the column might be beyond it's prime, and this could be due to a variety of problems including oxygen in the carrier gas, and more likely sample residues. If you have a GC-MS, typical bleed ions for low polarity columns (DB/HP-1 or 5 for example) will be m/z 207, 73, 281, 355, etc , mostly cyclic siloxanes. Question Q078 What are the steps to condition a Capillary Column? Answer A078 You should condition a new capillary column at approximately twenty degrees higher than the final temperature of your oven program without exceeding the upper temperature limit of the column. If a temperature higher than the isothermal temperature limit of the column is needed for your analysis, recondition the column at that higher temperature, but, again, don't exceed the upper program limit. When you install your column, purge it with at least three volumes of carrier gas prior to ramping it to the conditioning temperature. The total column conditioning time will depend on the type of application you're running and how much bleed is acceptable. The lower the detection limit that's needed, the longer the column will need to be conditioned. (Column bleed is closely related to the polarity and the film thickness of the stationary phase.) Polar and thick film columns bleed more and require more conditioning. For most applications, 30-60 minutes of conditioning is usually sufficient. But how can you really determine when a column is sufficiently conditioned? A flame ionization detector (FID) works best for monitoring the baseline during conditioning. Toward the end of the temperature ramp (i.e., 30-40§C below the isothermal upper temperature limit), the baseline will rise, then come down and level off, at which time you may consider the column conditioned. There are those that report detector fouling during conditioning when using other types of detectors (e.g., ECD, MS), but it's generally considered a safe practice to condition the column while connected to these detectors. Conditioning a column overnight is not recommended. Column life expectancy is greatly reduced when the column is stored at high temperatures. If you're experiencing an excessive amount of bleed for more than two hours, bring the oven down to room temperature and locate the source of the problem (usually oxygen entering the column from loose fittings or a leaky septum). Baseline signals that mimic column bleed can also originate from residues present in the GC itself. Additional note: if the column has not been in use for a while, a mild conditioning step may be needed to drive off contamination which may have condensed inside the column during storage. Also, there is nothing to suggest a limit to the ramp rate of the oven when conditioning a column. Question Q079 What are the steps to determine if a sample is causing damage to a capillary column? Answer A079 There is a quick and easy test to determine if your sample contains potentially damaging residues. Deposit about 20 µl of the sample onto a microscope slide. Set it over the heated injection port or on a hotplate until dry. If you can see any residue where the sample was deposited, that residue will likely cause chromatography problems at a minimum, and will potentially damage the column stationary phase. Question Q080 What are the Steps to Install a Capillary Column in the PCOC Inlet? Answer A080 Please refer the link for the video:How to install column in the Programmable Cool On Column (PCOC)inlet: https://www.agilent.com/en-us/products/gas-chromatography Question Q081 What are the steps to install a capillary column into a TCD? Answer A081 Please refer the document for the procedure on how to install a Capillary Column into a Thermal Conductivity Detector: https://www.agilent.com/cs/library/support/documents/F03046.pdf Question Q082 What are the steps to minimize and monitor column bleed? Answer A082 https://www.agilent.com/cs/library/support/documents/a16078.pdf Question Q083 What are the steps to minimize problems with water injections on capillary columns? Answer A083 https://www.agilent.com/cs/library/support/documents/F03016.pdf Question Q084 What are the steps to obtain maximum performance when using a deans switch with PLOT columns? Answer A084 Porous Layer Open Tubular (PLOT) columns have been replacing the traditional packed columns used for gas analysis because of advantages in resolution, speed and selectivity. But to get the best possible performance from these columns when working with the Deans Switch, you need to use the Flow Calculator (https://www.agilent.com/en-us/support/gas-chromatography/gccalculatorapplication) a free tool that you can download from the Agilent website to determine the effective (real) internal diameter (ID) of the column. Question Q085 What are the steps to reduce peak fronting? Answer A085 Fronting is column overload. It can occur when one or more of the compounds injected on the column exceeds the capacity of the liquid phase of the column. The thinner the liquid phase film, the less of each compound can be retained by the column. This includes both the injection volume and the concentration of each peak in the injection. Reduce the volume by injecting less, splitting the sample, or injecting a less concentrated sample. Question Q086 What are the steps to troubleshoot a retention time shift? Answer A086 There are many different causes for retention time shift in GC Chromatogram. Some of the possible causes are: 1 Change in carrier gas velocity: If all peaks will shift in the same direction by approximately the same amount; check the carrier gas velocity. 2 Aging of the column: Aging of the column can also cause a shift in retention time; this may require the column to be replaced. 3 Change in column temperature: If Not all peaks will shift by the same amount; check column temperature. 4 Change in column dimension: If you Switched column; verify column identity. 5 Large change in compound concentration: Large sample concentration may also affect adjacent peaks; use a different sample concentration. 6 Leak in the injector: Leak check the inlet. 7 Blockage in gas line: Most common for split line. Check flow controllers and solenoids; clean or replace clogged line 8 Contaminated samples: Samples containing large amounts of nonvolatile or semi volatile residues can quickly contaminate the capillary column and GC system. This contamination can also cause retention time shifts. Question Q087 What are the steps to troubleshoot baseline instability? Answer A087 Baseline problems arise from many causes. Some of these are: • Electronic or mechanical failure • Contamination in critical areas, such as detectors • Incorrect or inappropriate setpoints • Leaks, column or septum bleed, or other chromatographic difficulties These problems may interact to a certain degree and or arise from any of the above areas. Baseline Symptoms: Position 1. Baseline not at left (lower) part of chart: -Check the zero of your recording device: An attenuation or range change during the run may be responsible. -Check the TCD polarity. 2. Baseline position changes suddenly during the run: -This usually results from a range or attenuation change. -It can also result from valve operations: If valves are being switched during the run. -Septum leak Wander and Drift Baseline wander and drift may occur when a flow or temperature setting is changed. If the system is not stabilized at the new conditions before starting a run, some baseline changes are to be expected.(The following assumes that sufficient time has elapsed for stabilization.) 1. Baseline moves steadily upscale or downscale (drift) during the run: -This is most frequently seen during temperature programming: Operation with asingle column (no column compensation) at moderate to low attenuation causes this. If dual columns are used, check that the signal mode is correct for column compensation. -It is also possible that the compensation is insufficient or too great. Thorough column conditioning minimizes (this cause of drift). 2. Baseline erratic, moves up and down (wander): - Suspect a leak in the system: Check septum condition and replace if necessary. Check column connections. - If there is a leak at the detector end of the system then retention times should be stable and only sensitivity is reduced. A leak at the inlet end of the column will result in decreased sensitivity and delayed retention times. Noise Noise is rapid vertical baseline fluctuations, broadening the baseline and giving it a hairy appearance. Noise is different from spiking; spikes are isolated events, rather than almost continuous. Some noise is inevitable with any detector. At high attenuation it is invisible but appears as attenuation is decreased. 1. Noise appears suddenly on a previously clean baseline: -Consider all changes made recently to the system: Reduced attenuation for example. -New septa may contribute noise from bleed of low molecular weight material. If noise decrease when inlet temperature is lowered, this is the likely cause. -Contaminated carrier gas: Check to see if a new tank was replaced recently,replace with a different lot number. If the new gas was badly contaminated it may have contaminated the traps and changing the tank may not show any improvement until the traps are regenerated. -Contaminated detector gases (hydrogen or air) -Air currents from a fan or air conditioner blowing across the top of the instrument may interfere with gas exiting from the detector. -A contaminated detector results in noise. 2. Noise increases gradually to an unacceptable level: -This indicates a gradual build up of the noise source, rather than an abrupt change as discussed above. Flame ionization detectors are susceptible to build up of deposits in the collector. In extreme cases spiking occurs along with increased noise level. -Silicon dioxide deposits are formed when bleed from a silicone column is burned in the flame. This material is removed mechanically. Preventative measures include use of low column loadings, stationary phases with high temperature limit, thorough column conditioning before use, and the lowest possible oven temperatures for the analysis. -Carbon deposits may form from solvents that burn poorly (chlorinated and aromatics). If possible, avoid such solvents. If they are necessary, periodic cleaning of the collector is required. -Gradual noise increase may occur from saturated carrier gas drier or chemical traps. When these approach their capacities, contaminants begin to pass through and create noise. Trap and drier regeneration or replacement eliminates this source of noise. Spiking Spikes are isolated baseline disturbances, usually as sudden and large upscale movements. If accompanied by noise, the noise problem should be solved first, since spiking may disappear at the same time. 1. Spikes appear whenever the chart is running: -The cause is almost always electronic in origin: Loose connections are likely. Check signal cable connections at the detector and controller ends. -Loose or dirty contacts between printed circuit boards and their connectors may be responsible. 2. Spikes appear on chromatograms but not when the recorder is isolated, (no input signal): -This could be indicative of a detector problem: For example, an extremely dirty FID collector. -If a metal or glass packed column is being used column material could have been blown into the detector: FID and NPD are more susceptible due to the narrow bore of the jet. Systematically troubleshooting the GC is key to understanding and diagnosing the cause of baseline problems. Isolating the problem can usually be accomplished by simply identifying what was changed last. If problems still occur after stepping through the suggestions in this document please call for Agilent Technical Assistance. Question Q088 What causes peak fronting? Answer A088 https://www.agilent.com/cs/library/support/documents/a20826.pdf Question Q089 What causes peak tailing? Answer A089 https://www.agilent.com/cs/library/support/documents/a20825.pdf Question Q091 What columns and flow rates are acceptable for proper operation of the MSD? Answer A091 Acceptable flow rates vary by the model and pumping system of the MSD. 5970's are limited to 1.0, 5971 and 5972 models to 1.5, 5973 diffusion pump models to 2.0 and 5973 turbo pumps to 4 ml/min. The largest inner diameter (I.D.) column that can fit into the transfer line is 0.53mm. To determine what combination of column dimensions (I.D. and length) would give acceptable flows, download the pressure / flow calculator (https://www.agilent.com/en-us/support/gas-chromatography/gccalculators) that applies to your operating system. Question Q092 What happens if I order using the current GC Column part number? Will I receive the improved columns? Answer A092 You will continue to receive standard columns when placing an order using the current part numbers as long as we have inventory. Until then, to receive the new improved columns, you will need to place an order using the new part numbers. Once inventory of the standard columns is depleted, the current part numbers will become obsolete and will be replaced with the new part numbers. At that point you will receive the improved columns if you happen to place an order using the current part number. Go back to HP-INNOWax - https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary/hp-innowax#support and/or CP-Wax 52 CB - https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary/cp-wax-52-cb#support Question Q093 What is "LTM" Technology? Answer A093 In brief, the "LTM" (Low Thermal Mass) technology interweaves heating and temperature sensing components wound directly around a capillary column for rapid and efficient heating/cooling. This greatly reduces analytical cycle times addressing customers demands for greater productivity and low power consumption and also even allows use in portable/transportable applications. For more information, please see the Technology section in FAQs. Question Q094 What is the correct distance a column should be installed in the GC Inlet? Answer A094 https://www.agilent.com/cs/library/quickreference/public/GC%20Column%20Installation%20Quick%20Reference.pdf Question Q095 What is the Maximum Operating Temperature for a Module? Answer A095 The components that are combined by Agilent with the capillary column generally have much higher temperature ratings than the columns themselves. Since very few columns can program above 400°C, the practical maximum temperature for programming was limited to 400°C. We recommend that modules are never programmed beyond the column temperature limits recommended by Agilent or other GC column manufacturers, and this is usually a temperature significantly below 400°C. With very fast ramping applications (e.g. 600 °C/min), limiting the maximum temperatures to 10-20°C below the maximum operating temperature for programming recommended by the manufacture can increase the module's cycle lifetime. Question Q096 What is the procedure for installing a GC column in to GC-FID, GC-TCD, µECD and/or GC-MSD? Answer A096 https://www.agilent.com/cs/library/packageinsert/public/PN%20830-0120.pdf Question Q097 What types of GC Columns can be used? Answer A097 All types of capillary GC columns can be used in the column modules for the Agilent LTM/MACH/LTM A68 systems including both wall coated open tubular capillaries (WCOT) and PLOT capillaries with some exceptions. Any of the capillaries can be put into the 5" module size, and the 3" module size is compatible with nearly all WCOT capillaries with a fused silica i.d. of 0.32mm or less. The 3" module size is not recommended for PLOT columns or any capillary column that is known to be especially fragile. The column module technology is compatible with metal capillary columns, but these are generally not recommended for fast GC applications because of their poor cooling performance compared to fused silica capillaries. A full selection of capillary columns available from Agilent Technologies in lengths up to 30m with a few exceptions (e.g. DB-VRX 40m x 0.18mm x 0.1mm). Please note that columns can be trimmed to custom lengths; column lengths in column modules are not limited to standard lengths . Columns from other manufacturers can be procured through Agilent custom column ordering procedure. Please refer to the FAQ for ordering LTM column modules. Question Q098 What would happen if I don't install the thermal shield? Answer A098 The new thermal shield reduces the risk of burns in the event someone accidentally touches the RVM LTM (or Gerstel MACH) column module(s) while it is hot. Question Q099 What’s the difference between the standard columns and the improved versions? Answer A099 Better performance.The improved columns provide: Excellent inertness and peak shapes for diols, amines, acids and ethyl maltol Exceptional column-to-column reproducibility Improved inertness longevity Extended inertness lifetime that withstands repeated cycling to the upper temperature limits of the column Go back to HP-INNOWax - https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary/hp-innowax#support and/or CP-Wax 52 CB - https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary/cp-wax-52-cb#support Question Q100 Why are peaks of interest showing up in blanks? Answer A100 This can be a sample preparation or system cleanliness problem. Try new solvents, both the ones for sample and blank preparation, as well as the solvents in the sample wash bottles. Try a new syringe and septum. Remove and clean the split vent line. Make a run without any injection, to see if the peaks show up just by heating the column. Question Q101 Why are the peaks smaller than expected (poor sensitivity)? Answer A101 Low Peak Area or Height • If using an inlet in split mode, check the split ratio. • Check for leaks. • Check the inlet for contamination. • Check each column and verify that it was cut and installed properly at each end. • Verify that the column type is correct. • Perform column maintenance: Bake out contaminants, remove the contaminated length of column near the inlet, and reverse and bake out the column as needed. • Verify that the liner type is appropriate for the sample. • Verify that the detector flow settings are correct. • Check the supply gas purity. • Check all trap indicators and dates. • Verify that the method parameters are correct. • Check sample stability. • Check configured syringe size. Some syringe sizes are specified at half-capacity. If the maximum syringe volume is marked at half-height on the barrel, not at the top of the barrel, enter twice the labeled volume when configuring the syringe size. If using an FID: • Verify that the correct jet is installed. • Check for a dirty jet. If using a uECD: • Replace the fused silica indented mixing liner. • Replace and reinstall column. • Clean the makeup gas adapter. If using an NPD: • Check the detector for contamination. • Replace ceramic insulators. • Replace the bead. If using an FPD: • Verify correct column installation. • Check that the correct filter is installed and is clean. • Check the flow rates. • Check the makeup gas type. Question Q102 Why are there unwanted (ghost) peaks in the 7890A GC chromatogram? Answer A102 Contamination or Carryover If your output has contamination or unexpected peaks, do the following: Isolate the source 1 Perform a solvent blank run using a new, pure source of solvent. If the contamination disappears, the problem may be either in the sample or solvent-related. 2 Perform a blank run (remove the syringe from the injector and start a run). If the contamination disappears, the problem is in the syringe. 3 Remove the column from the detector and cap the detector fitting. Perform another blank run. If the contamination disappears, the problem is in the inlet or column. If the contamination remains, the problem is in the detector. Check possible causes all inlet and detector combinations • Check the septum type and installation. • Perform complete inlet maintenance: Replace all consumable parts and bake out the inlet. • Perform column maintenance: Bake out contaminants, remove the contaminated length of column near the inlet, and reverse and bake out the column as needed. • Check for sample carryover from previous runs. Make several no-injection blank runs and see if the ghost peaks go away or get smaller. • Check the septum purge flow. If it is too low, the septum may have collected contamination or condensate may be clogged in the purge line. • Check all gas trap indicators and dates. • Verify the gas purity. Check for supply tubing and fitting contamination. • If you suspect that there is contamination in the inlet, column, or detector, perform the bakeout procedure. • Verify that the oven program temperature and time are sufficient for the samples being injected. • Check the solvent level in the ALS wash bottles. • Replace the ALS syringe if necessary. • Check the sample injection volume. • Install an Agilent column backflush system. Question Q103 Why do I occasionally get a PLOT column with what looks like a spot or spots in the column? What causes this? Will this affect the performance of the column? Answer A103 The spots you are seeing are small voids in the stationary phase coated inside of the tubing. It is normal to have some voids in the phase coating of PLOT columns. The columns are individually tested and verified to exhibit the correct chromatographic performance. Agilent guarantees the reliability and performance of our products with a 90-day warranty for all of our GC columns. Question Q104 Why does my column look different? Answer A104 In the past couple of years, we have taken steps towards standardizing the appearance of all our Agilent J&W Capillary GC Columns. The first step was the standardization of the outer diameters of the fused silica tubing followed by consistent labeling of the column boxes. Now we have standardized the cage design of all capillary GC columns. Question Q105 Why does the instrument have trouble tuning after a column replacement? Answer A105 A likely cause for this is the column was installed too far into the MS. Be sure to use the column installation tool to install the column. The instructions can be found in Chapter One, of the Hardware Manual. Question Q106 Why improve HP-INNOWax and CP-Wax 52 CB columns? Answer A106 https://www.agilent.com/en-us/support/gas-chromatography/gc-columns/capillary/hp-innowax-cp-wax-52-cb-improvements Question Q107 Why is the effective internal diameter of the PLOT Column necessary when using the deans switch? Answer A107 Normally, there is a difference between the labeled column ID value and effective ID. Although this difference is small, it is significant enough to make a difference when you determine the correct restrictor dimension by Deans Switch Calculator and balance the Deans Switch flows. Question Q108 Will I experience any selectivity difference with the new GC Column? Answer A108 https://www.agilent.com/en-us/support/gas-chromatography/gc-columns/capillary/will-i-experience-any-selectivity-difference Question Q109 Will the EZ-Grip fit the updated column cage? Answer A109 The EZ-Grip will not fit the standardized column cage and will be obsolete. Question Q110 Will the improved columns fit my regulated method? Answer A110 https://www.agilent.com/en-us/support/gas-chromatography/gc-columns/capillary/will-the-improved-columns-fit-my-regulated-method
General
Question Q112 Where do I find the Certificate of Analysis for my product? Answer A112 https://www.agilent.com/search/?N=137&Ntt=cofa Question Q113 Where do I find the Material Safety Data Sheet (MSDS) for my product? Answer A113 http://www.chem.agilent.com/en-US/Search/Library/Pages/MsdsSearch.aspx
Inlets and Liners
Question Q001 What are the steps to increase filament life? Answer A001 The ion source filament emits electrons when heated by the emission current. The emitted electrons ionize the sample molecules introduced into the source chamber. There are 2 filaments installed on the ion source. They eventually burn out. To extract more life out of them: - Use proper solvent delay time so that the filaments are off, when the large solvent peaks are eluting. - Reduce the emission current to increase the filament life. - Make sure the MS does not have leaks and your system operates in specified vacuum conditions. - Always bakeout the system after any maintenance to reduce moisture in the manifold. Question Q114 What are the steps to chemically deactivate injection liners? Answer A114 The deactivation process entails two basic steps: a leaching step to remove metal oxides at the glass surface and a derivatization step to deactivate surface silanols. Leaching involves soaking the inlet liner in a 25% mineral acid solution (e.g., hydrochloric, nitric, and sulfuric acids, but not chromic acid), usually overnight at room temperature. This portion of the deactivation process can be shortened to several hours if the acid solution is mildly heated (65?C). The derivatization step is more involved. After leaching, the liner is heated to remove free and bound water from the surface of the glass2), and then it is derivatized with a chemical agent to deactivate the surface silanol groups The choices for derivatizing agents are numerous, and methods are just as varied. Although simple deactivation procedures exist, and are fairly effective (40-50%), the procedure is a very thorough deactivation procedure, which produces a more chemically inert liner than is commonly commercially available. This procedure is especially effective for very active compounds. For more information on the properties of glass and chemical deactivation, we recommend two books: 1. Walt Jennings: Analytical Gas Chromatography, Academic Press, and Comparisons of Fused Silica and Other Glass Columns in Gas Chromatography. 2. Dean Rood: A Practical Guide to the Care, Maintenance, and Troubleshooting of Capillary Gas Chromatographic Systems, offers discussions on poor peak shape and activity phenomena. Question Q115 What are the steps to clean the GC injection port liner? Answer A115 Cleaning the injection port liners can cause expensive instrument down time when done incorrectly, or incompletely. Liner quality is specific to each application and there is no general method for cleaning liners. We cannot recommend a general method. Question Q116 What indicates the liner or glass wool need replacement? Answer A116 Monitor the performance of your chromatographically problematic compounds, typically these are the ones with reproducibility problems in replicate injections and organic acids and bases. When check standard performance becomes unacceptable, replace both the liner and glass wool. Question Q117 What indicates the need to change the septum or liner? Answer A117 Typically modern septa can last 100 injections or more before problems start to occur. Liners need to be changed when chromatographic symptoms indicate a problem. Factors that affect the septa lifetime are syringe size, inlet temperature and to a lesser extent, pressure. Factors that affect liner lifetime are usually due to sample cleanliness. You should rely on the history of the instrument maintenance to tailor your specific program around chromatographic needs. Question Q118 What is the appropriate amount of glass wool in a liner? Answer A118 For splitless, only a loose plug of maybe a couple millimeters. For split, maybe an 1/8´´ or so if at the bottom of the inlet, or if it is placed above where the needle bottoms out to control the pressure pulse and wipe the needle, then about 3/4´´.
Lamps
Question Q119 Are there any performance compromises with multi-element lamps? Answer A119 Multi-element lamps can provide similar performance to that obtained using single element lamps. Depending on the lamp, there may be some trade-off in calibration graph curvature and intensity of emission. In many instances, these 2 effects can be overcome by using Agilent UltrAA (high intensity boosted discharge) lamps. The other compromise is that some wavelengths may not be available in a multi-element lamp because of spectral interferences. Question Q120 Are there storage guidelines for AA lamps? Answer A120 Hallow Cathode Lamps do not have an expiry date or shelf life. The lamp is totally sealed (like a light bulb) so even though it may be in storage for a while, we don’t expect to see any degradation in performance. You can check the lamp by checking the gain setting located on the lamp optimization screen in the software. If necessary check for an emission peak at the appropriate wavelength using a lamp emission scan. You should keep a record of the gain setting and confirm that it does not change significantly from the last test. A faulty lamp will show a glow from the cathode - but the gain setting will be very high - and the instrument will report an error message (either low lamp energy or it may show a "peak not found" error). There is also an AA at Work publication (application note) that may be a useful reference as it provides more detail to help users learn more about the design characteristics and operation of using hollow cathode lamps and deuterium lamps. https://www.chem.agilent.com/Library/applications/aa083.pdf Question Q121 Can all lines be used in multi element lamps without interference? Answer A121 All the usual primary lines may be used with Agilent multi-element lamps. The primary lines have been checked for spectral interference and minimal or no interference has been noted. The secondary lines have not been checked and for this reason only, the use of secondary lines is not recommended. Where there are interferences, the use of Agilent UltrAA (high intensity boosted discharge) lamps can help to minimize these effects. Question Q122 Can spectral interferences be overcome? Answer A122 Yes. The use of UltrAA (high intensity boosted discharge) lamps minimizes these effects. Question Q123 Do any lamps have solid cathodes? Answer A123 Cathodes for lamps such as Cu, Fe, Ni and Al are machined from the solid metal. Lamps such as V, Pd, Au and Ir have sheet metal inserts. These are all single element lamps. There are a variety of multi element lamps available with up to six elements incorporated into a single lamp. Multi element lamps have similar performance to a single element lamp in the convenience of one lamp. Question Q124 Do other elements in the cathode affect the lifetime? Answer A124 No. Lamps should exceed 5000 mA hours of operation regardless of the element actually determined. Question Q125 Does the flickering glow around the anode mean that the lamp is faulty? Answer A125 No. This is a consequence of current flowing through low-pressure gas. It has no effect on the atom plume. "Lamp flicker" applies only to emission from the cathode. Most emission lines emitted by the lamp are in the UV region, which is not visible to the naked eye. Use the % gain (or EHT value) displayed at the Optimize page to determine whether a lamp is faulty. Good lamps, properly aligned, should have a low % gain value (or low EHT value) and a fairly steady emission signal. Danger signs are a high % gain value (or high EHT value) and a fluctuating emission signal. The best indication of a lamp failing is an increase in the % gain (or EHT) value (displayed at the Optimize page) when compared with the value obtained when the lamp was new. The % gain and EHT values vary from one element to another, so a typical elevated figure cannot be quoted. The best way to determine whether the lamp is deteriorating is to monitor the % gain and the EHT value from new. See also What are the typical % gain or EHT values for hollow cathode lamps? https://www.agilent.com/en-us/support/icp-ms/kb005762 Question Q126 How do I dispose of my hallow cathode lamp? Answer A126 You can dispose of old or used hollow cathode lamps in accordance with local EPA or Government regulations for regular vacuum lamps (or globes). Hollow cathode lamps contain small quantities of chemicals (usually less than 5 grams per lamp) and the lamps should be disposed of in a responsible manner because of these chemicals. Question Q127 How do you know when a lamp is worn out? Answer A127 The best indication of a lamp failing is an increase in the % gain (or EHT) value (displayed at the Optimize page) when compared with the value obtained when the lamp was new. The % gain and EHT values vary from one element to another, so a typical elevated figure cannot be quoted. The best way to determine whether the lamp is deteriorating is to monitor the % gain and the EHT value from new. Question Q128 How much fill gas is added? Answer A128 After the lamp has been processed, it is evacuated and back-filled with high-purity neon or argon. The fill gas pressure is carefully selected to give the optimum balance between lamp intensity and useful operating life. Argon is only used when a neon spectral line would interfere with the wavelength for the selected element. Question Q129 Is there a compromise in intensity with the Ag/Cd/Pb/Zn or Al/Ca/Mg multi elements lamps? Answer A129 Ca, Cd, Mg, Pb and Zn are present in the optimum solid concentration. The respective intensities are comparable to those of the single element lamps. The relative intensities of Al and Ag are less compared with the single element versions. These elements are so intense anyway that the reduction has no real practical disadvantage. Question Q130 What additional information is available on lamp construction and operation? Answer A130 Please see AA at Work (Application Paper) No. AA-83 (PDF file) titled "Features and Operation of Hollow Cathode Lamps and Deuterium Lamps" - https://www.agilent.com/cs/library/applications/aa083.pdf Question Q131 What are the steps to perform a DAD intensity test using the ChemStation? Answer A131 https://www.agilent.com/cs/library/support/documents/A25845.pdf Question Q132 What are the steps to perform a DAD wavelength calibration test using a control module? Answer A132 https://www.agilent.com/cs/library/support/documents/A25872.pdf Question Q133 What are the steps to perform a DAD wavelength calibration test using the ChemStation? Answer A133 https://www.agilent.com/cs/library/support/documents/A25844.pdf Question Q134 What are the Steps to Perform a FLD Dark Current Test using the ChemStation? - 1100 Series LC Answer A134 https://www.agilent.com/cs/library/support/documents/A25861.pdf Question Q135 What are the steps to perform a FLD lamp intensity test using the ChemStation? Answer A135 https://www.agilent.com/cs/library/support/documents/A25859.pdf Question Q136 What are the steps to reset the lamp hours on a DAD, MWD or VWD? Answer A136 In the Diagnosis level of the ChemStation software, click on the icon for the detector. You will see a drop-down menu. Choose Show Module Details. You will see an icon of a logbook and a wrench. Click on this icon, and you will see another drop-down menu. Select Maintenance Logbook Entry. Choose the Maintenance Message entry Lamp Replaced. The ChemStation software will prompt you to reset the counter. Question Q137 Vacuum Measurement: What are the steps to reset the gauge controller if it is displaying strange readings? Answer A137 Reset the controller to the factory default settings. First, write down all settings that have been changed since the last reset. Then enter an access code of “81”. To do that: On a Multi-Gauge, press the F key and then the VAC key. “A00” will display, with the left-hand 0 flashing. Press the up or down arrow keys until the left-hand digit is “8”. Press the F key. The right-hand digit will begin flashing. Press the up or down arrow keys until that digit is “1”. Press the F key again. On a senTorr, press the ENTER key and then the UNITS key. “A00” will display, with the left-hand 0 flashing. Press the up or down arrow keys until the left-hand digit is “8”. Press the ENTER key. The right-hand digit will begin flashing. Press the up or down arrow keys until that digit is “1”. Press the ENTER key again. Question Q138 What are the typical life times of a cathode lamp? Answer A138 Typically lamps last at least 50 % longer than the warranted period - this means typical lifetime is ~ 8000 mA hours. This is a general indication only. Some of the lamps that have been put through lifetime tests have lasted in excess of this lifetime. Question Q140 What causes baseline noise and drift after replacing the DAD lamp and flow cell? Answer A140 The problem could be flow related. Remove flow cell and check the baseline. If no problem, then flow cell could be contaminated (replace/clean windows) or pump/sampler could be the source. or the problem could be in optics or part of the optics.Check by replacing either Source Lens assy P/N G1315-65201 as a whole (or individual parts of it like Spectro window P/N 79880-28111 and Lens Achromatic P/N 1000-0486) or Cell Support Windows G1315-65202. If the problem persists please contact your nearest Agilent technical representative. Question Q141 What indicates the FLD lamp is on? Answer A141 If the user-interface shows the detector 'Ready' (the ChemStation shows the FLD still in green) but you do not get a signal, how can you check whether the lamp is on or not?Unfortunately, there is no feedback mechanism like on the DAD/VWD that turns the FLD into a 'Not Ready' condition.If no signal is available, then enter the diagnostics level of the software and perform an Instrument Profile. If that is flat (less than 100 counts) the lamp is off. In this case, check whether the flow cell is tightened into place. For safety reasons the lamp will be turned off when the flow cell is removed or not completely tightened in place. Question Q142 What is the approximate life of UV Detector lamps? Answer A142 The lamp life depends on the operating conditions. The parameters like number of ignitions and the lamp ON time (the duration the lamp is ON) have an impact on the lamp life time. The Deuterium lamp life time is about 2000 hours, the Tungsten lamp lasts for more than 3000 hours. The self test results give you hints on the available intensity by spectral region. If the intensity in the visible range is low, you should also check the Deuterium lamp bulb for transparency. If it shows a coating or dark soot the Deuterium lamp must also be replaced. Please contact your local Agilent Technologies representative if you need more details. Question Q143 What is the approximate lifetime of UV detector lamps? Answer A143 Please note that P/N 5181-1528 will be replaced by P/N 5181-1530.P/N 5181-1528 will be available as long as stocks exist. https://www.agilent.com/cs/library/support/documents/FAQ1022%20F01053.pdf Question Q144 What is the black spot? Answer A144 The black spot is produced deliberately. This deposit on the inner glass envelope ensures that the fill gas is free of impurities and contributes to the long shelf-life of Agilent lamps. During processing, we subject the zirconium anode to ion bombardment. This vaporizes a small amount of anode material and deposits it on the lamp envelope near the anode, creating the characteristic black patch. This zirconium metal film is highly reactive and acts as a very efficient scavenger of traces of oxygen and other impurity gases that might otherwise reduce the lifetime of the lamp. It is called a "getter". The black "getter" spot behind the anode helps to prolong the useful life of the lamp - and also ensures continued spectral purity throughout the life of the lamp. Question Q145 What is the purpose of the fill gas? Answer A145 The fill gas allows the sputtering of the cathode material. The fill gas is ionized when a high voltage is applied between the electrodes. These ions are accelerated towards the cathode. When they hit the cathode surface, they knock metals atoms loose. The atom plume thus formed is excited by further collisions with other high energy particles during this process. The excited atoms are unstable and relax back to their ground state, emitting radiation characteristic of that element. For most elements, more than one analytically useful spectral line is generated. Question Q146 What type of testing do lamps undergo during production? Answer A146 All lamps are tested to confirm that the desired emission spectrum exceeds an acceptable value and that the lamp provides good stability (low drift). No lamp leaves our factory without having satisfied our demanding test standards. These tests ensure that you receive lamps of the highest quality with excellent sensitivity and optimum signal-to-noise performance throughout the life of the lamp. Specifically, each lamp receives the following testing: High voltage isolation, Strike voltage, Performance (EHT and noise), Drift test (lamp stability), and Lamp recognition (for coded lamps). Question Q147 Why do lamps wear out? Answer A147 The most common cause of lamp failure is that which claims most pieces of scientific glassware: physical damage from rough handling or accidents. Even the most carefully handled lamp will eventually fail to operate however, as the fill gas is absorbed into the internal surfaces of the lamp. In time, the pressure of the fill gas will fall to a level that can no longer sustain the hollow cathode discharge. This will be manifested in both an erratic cathode discharge or complete failure to "strike". Operating the lamp at excessive lamp currents will accelerate this process. Attempts to run a lamp at extreme currents can cause the cathode to overheat, and this can damage the cathode. This is especially true for the more volatile elements. To get the most out of a lamp, handle it with care and do not exceed the recommended operating current. Question Q148 Why does a new lamp look used? Answer A148 Processing is a vital step in lamp production, which aims to remove impurities from the lamp. During processing, the cathode material is heat treated under vacuum to ensure that all absorbed gases are removed. During this purification stage, a layer of the cathode material is deposited on the inside of the glass envelope of the lamp. The amount of material deposited varies, depending on the volatility of the element. The extended processing cycle and use of specially pure materials ensures dependable performance from Agilent hollow cathode lamps. Question Q149 Why does my hallow cathode lamp looked burned inside? Answer A149 In the lamp purification and processing operation, the polarities of the cathode and the anode in the lamp are reversed so that the zirconium anode now becomes the cathode. This subjects the zirconium anode to ion bombardment. During this discharge a small amount of the zirconium anode material is vaporized and deposited on the inside envelope of the lamp. This is the dark film visible on the glass envelope near the anode. Zirconium is a very active “getter” for impurity gases such as oxygen and hydrogen, and this discharge serves to purge the lamp of these impurity gases. That is, this activated film of zirconium will absorb any impurity gases that may have escaped the previous purification stage. This “black patch” that is visible on the inside of the lamp ensures that the fill gas is free of impurities and contributes to the long shelf life of Agilent lamps – and also ensures continued spectral purity throughout the life of the lamp. Finally the lamp is then filled with spectroscopically pure gas and sealed. Processed lamps are then operated for several hours prior to testing. The extended processing cycle and use of specially pure materials ensures dependable performance from Agilent hollow cathode lamps. For further details on the features and characteristics of the hollow cathode lamp, please refer to the Agilent Application Note titled “Features and Operation of Hollow Cathode Lamps and Deuterium Lamps” available from the Agilent literature library on the Agilent website www.agilent.com/cs/library/applications/aa083.pdf Question Q150 Why treat the cathode? Answer A150 When lamps are fully assembled, they are subjected to an aging process during which the lamp is operated under controlled conditions. This ensures that the lamp is ready for immediate use when it is taken out of its shipping box. All "settling in" of the lamp is completed before the lamp leaves the factory. After aging, the lamp is subjected to thorough testing. No lamp leaves our factory without having satisfied our demanding test standards for intensity and stability. See also What type of testing do lamps have during production? All lamps are tested to confirm that the desired emission spectrum exceeds an acceptable value and that the lamp provides good stability (low drift). No lamp leaves our factory without having satisfied our demanding test standards. These tests ensure that you receive lamps of the highest quality with excellent sensitivity and optimum signal-to-noise performance throughout the life of the lamp. Specifically, each lamp receives the following testing: High voltage isolation, Strike voltage, Performance (EHT and noise), Drift test (lamp stability), and Lamp recognition (for coded lamps).
LC Columns
Question Q151 Agilent AdvanceBio Peptide Mapping Columns Specifications Answer A151 https://www.agilent.com/en-us/support/liquid-chromatography/kb005975 Question Q152 Agilent Bio IEX Column Specifications Answer A152 https://www.agilent.com/cs/library/datasheets/public/5991-6120EN.pdf Question Q153 Agilent Bio SEC-3 Column Specifications and Options Answer A153 https://www.agilent.com/cs/library/selectionguide/public/5990-9384EN.pdf Question Q154 Agilent Bio-Monolith Column Specifications Answer A154 https://www.agilent.com/cs/library/datasheets/public/5991-6040EN.pdf Question Q155 Agilent ZORBAX Bio SEC-5 Column Specifications and Options Answer A155 https://www.agilent.com/cs/library/selectionguide/public/5990-9384EN.pdf Question Q156 Bio LC Column User Guides Answer A156 https://www.agilent.com/en/support/liquid-chromatography/kb005960 Question Q157 Can I really effectively use these very short columns on my HPLC instrument? Answer A157 Yes, you can. For columns of 3.0 mm i.d. and above, no instrument adjustments are necessary. For gradient separations with 2.1 mm and 1.0 mm i.d. columns the ideal HPLC is a high-pressure mixing instrument — like the Agilent 1100 HPLC with the binary pump, because it minimizes the gradient delay volume. Using a low volume mixer and the injector by-pass (or micro-injector) further minimize gradient delay volume. Narrow i.d. tubing and a low volume detector flow cell are preferred but not necessary. These changes are easy to make and allow you to effectively use columns as small as the 2.1 x 30 mm columns or even the 2.1 x 15 mm columns Question Q158 Do you think that using toluene as a standard for measuring GPC column efficiency is appropriate? Answer A158 Yes. Conditions for this evaluation are chosen so that the small molecule toluene does not interact with the packing, but diffuses through all the pores of the GPC column packing. By conducting the experiment in this way, the width of the eluting peak is a function of the particle size of the packing and how well the column bed is packed. That's what you want to know when you are measuring efficiency. This sample is commonly used and recommended by most manufacturers to test efficiency of these columns. Alternate standards may be used to determine other characteristic of a GPC column, e.g., exclusion volume. Question Q159 How can one properly wash GPC columns (safely)? Answer A159 Wash the column in the reverse direction, not attached to the detector and at half the recommended flow rate (keep the pressure below the recommended maximum). First choose a solvent that will dissolve what you believe has contaminated the column. Most GPC columns are PS-DVB and you need to check the solvent compatibility before using a solvent. Many wash solvents are a higher viscosity than the typical eluting solvents so a lower flow rate with careful attention to pressure is needed. Anionic samples can adsorb onto PS-DVB and if these have contaminated your GPC column a wash solution with a salt is recommended. Check to see what types of salts are recommended for the column. In some cases the polarity of the material adsorbed may require washing with organic solvents modified with acid (formic or acetic) or base (triethanolamine) (check the pH range) or some water may be compatible with an appropriate organic solvent. If more hydrophobic material were retained, elevated temperature along with an appropriate organic solvent would be recommended. Once again you need to check the maximum temperature range allowed for your column. If you wash carefully the column should not degrade from the solvent switching. Question Q161 How do I perform column conditioning for IP391/07 Diesel analysis? Answer A161 The column sequence should be SB-CN first and Zorbax NH2 second. The NH2 column needs a conditioning step before use according the attachment. The used solvent must be extremely dry to avoid retention time and separation changes. Question Q162 How do you clean C4 column? Answer A162 Much as you would any RP-phase column and I've included some general instructions provided that you are using standard mobile phase conditions to separate small molecules. If you are separating peptides and proteins or if your sample is dissolved in plasma, then the guidance is different and I recommend that you call 800-227-9770, press option 1 and ask for HPLC column technical support for more information (within the US, other areas contact your local Agilent sales office. Question Q163 How do you evaluate for column voids? Answer A163 First check your method and find out if you have operated at a pH higher than is recommended for the column. This is probably the major cause of column voids because silica can dissolve causing the column void. The sample injection solvent as well as the mobile phase needs to be considered here. If there is a column void, you will see a change in peak shape - tailing, broadening, or split peaks - on every peak in the chromatogram. A void will not usually cause a change in only one peak in the chromatogram. It also does not typically cause a change in analyte retention. You can also turn the column around and if there is a column void then the peak shape should be poor in the reverse direction as well. The only definitive way to check for a column void is to open the column and this should be done only as a last resort in identifying the problem with the column. Question Q164 I can’t get enough retention of my basic compounds at low pH, what column should I try next? Answer A164 The Eclipse XDB column can be used in the intermediate pH region — from pH 3 - 8 for the longest lifetime. The primary advantage of using the intermediate pH region is a possible increase in retention for basic compounds. Most basic compounds have pKa values of 5 or greater, therefore at pH 6 - 8 some of these compounds may become non-charged and the column will retain them more. In addition, at pH > 5 the residual silanols on the silica surface will become charged. This can lead to stronger interactions with basic compounds and increase retention. The Eclipse XDB column is the ideal column to use in this mid-pH region because the dense-bonding and double end capping will cover the most active silanols on the surface of the column, and any residual silanols can contribute to increased retention of basic analytes without causing excessive peak tailing. Figure 1 shows a plot of retention vs pH for a group of basic compounds. At pH 6 and higher the retention of all of these compounds increases due to increased interaction with the column, though at pH 6.5 only Triprolidine is non-charged. If retention has not increased enough, then the next step would be to try the Extend-C18. All of the basic compounds shown in Figure 1, except Triprolidine, have pKa values of 9.0 - 9.2. Therefore they must be analyzed at pH 10 or higher before they are non-charged. The Extend-C18 can effectively be used at this high pH to improve the retention of basic compounds. Question Q165 I typically select 4.6 x 250 mm, 5 µm columns for my analytical work because I have complex samples, but I need to reduce my analysis time and increase my sample throughput. What can I do? Answer A165 Rapid Resolution columns are ideal for your needs. A Rapid Resolution 4.6 x 150 mm, 3.5 µm column will reduce your analysis time by 40% while maintaining your resolution. Your gains are in reduced analysis time, whether you are doing isocratic or gradient separations, and substantial solvent savings (Figure 5). You may be able to choose even shorter Rapid Resolution column lengths and maintain the desired resolution (Rs) because Rs a N1/2. This means that decreasing column length, and therefore efficiency, will not decrease Rs by the same amount. It is likely that resolution will be maintained on even shorter column lengths and choosing 75 mm or even 50 mm column lengths can reduce analysis time even more. Question Q166 I’m currently using a C18 column and my separation has a couple of peaks that elute early and a couple of peaks that elute late. What can I do to reduce the analysis time and maintain resolution of the early eluting peaks? Answer A166 First, you could try a gradient elution method on the C18 column. But many people do not like to use gradients, so choosing a different bonded-phase may help. Short chain polar bonded-phases such as the SB-CN and SB-Phenyl are ideal for separations like this. The increased polarity of these phases reduces retention of the later eluting hydrophobic compounds while often maintaining the retention of earlier eluting hydrophilic compounds. Figure 2 shows this clearly. Using the same mobile phase conditions these three compounds are well resolved on the SB-CN in about 5 minutes. The same separation on the SB-C8 column takes nearly twice as long and provides incomplete resolution. Question Q167 I’m trying to separate some very difficult basic compounds at pH 2.5 using a C18 column and their tailing factors are still too high — around 2.0. Which column should I try next? Answer A167 The Bonus-RP column would be a good column to try. This column has an amide group in the alkyl chain. This amide group reduces interactions between basic compounds and the residual silanols on the silica surface by acting as an internal competing base and reducing peak tailing of basic compounds. The Bonus-RP column, while ideal for the mid-pH range where silanol interactions are more likely, will also improve peak shape at low pH. The Bonus-RP column uses the same sterically protecting bonding used for StableBond columns. This improves the lifetime of the Bonus-RP column at low pH and makes it a good choice in situations like this. Question Q168 If one peak in a chromatogram is tailing but the others are not, what is the likely cause? Answer A168 Peak tailing can be caused by a variety of reasons and I would prefer to ask you several questions about your sample before I submit a response. Since most of the peaks in your chromatogram are well shaped and only one is tailing, I suspect that the chemistry of the column and sample are such that a secondary interaction is inducing the tailing. Modifying the mobile phase or selecting another HPLC column can reduce these secondary interactions. Question Q169 I'm having a problem with resolution and selectivity for a phenyl column using different lots, how can I resolve this problem? Answer A169 First, evaluate the methods used on each column. Are their any differences in the column histories or column equilibration procedures? Differences in either of these may alter the behavior of analytes on a column. Recently someone had a problem with a change in resolution and selectivity on two phenyl columns, which was resolved by flushing the column once again with 100% methanol. This may make a good starting point for you. In the case I just described we had a third column lot to compare it to so that when we flushed the column and retested the sample in its mobile phase we achieved the expected results and knew that this flush should be added to the equilibration procedures. Our typical recommendation would be to flush the column with 100% acetonitrile or methanol, which ever is used as the organic modifier in the mobile phase. In the case I described, only the methanol changed the column, possibly due to interactions with the phenyl rings in the bonded-phase. You should also make up fresh mobile phase and test it in case the problem occurred with the mobile phase and make sure the instrument is operating as expected. These steps will eliminate some of the potential sources of column-to-column variations. The next step is to review your method ruggedness. Are any of your analytes sensitive to pH or ionic strength? If slight changes in pH or ionic strength affect retention then you may need to modify your method and select conditions where changes in these parameters do not affect resolution and selectivity as much. Acidic and basic analytes can be very sensitive to pH and ionic strength changes around the pKa of the analyte. Finally ask the column manufacturer for assistance. They may be able to supply additional columns from older lots that have worked or from newer lots while the method is evaluated. The manufacturer may also be able to make some suggestions based on your method parameters. Question Q170 I'm working with environmental samples that may contain sulfur. I suspect that a few samples insufficiently cleaned up. Column performance has declined significantly. Is there any way to restore performance? Answer A170 I assume you are using a reversed-phase column. Please review the recommended HPLC column cleaning procedure . I do suggest that if column performance declined quickly that you consider using a guard column and possibly consider including a preliminary clean-up step before injection. Question Q171 Is a Rapid Resolution 3.5 µm column more likely to fail than 5 µm column? Answer A171 No. The Rapid Resolution columns are as rugged as the 5 µm, 250 mm columns. There are two types of accelerated column failure attributed to using smaller particles. First, smaller particle columns are thought to plug faster. This is not true when a standard 2 µm frit is used at the top of the column. Because of careful particle size control and the use of 3.5 µm particles, ZORBAX Rapid Resolution columns will not contain any particles as small as 2 µm. This means a standard frit can be used on the column and the Rapid Resolution columns will be no more prone to plug than a 5 µm particle size column. Second, columns with smaller particles are thought to have shorter lifetimes because the column beds compress, leaving voids that cause peak broadening and tailing. It is true that 3.5 µm particle size columns will operate at slightly higher pressures than 5 µm columns, but ZORBAX particles can easily withstand these increases in pressure. ZORBAX particles are packed at 8000 psi and can easily withstand pressures up to 5000 psi in routine use. A Rapid Resolution 4.6 x 150, 3.5 µm column will typically be operated below 3000 psi, so the column bed will not compress when using ZORBAX Rapid Resolution columns. So both the rugged ZORBAX particles and the standard 2 µm column frit assure you long column lifetime when using Rapid Resolution columns. Question Q172 Is there a way to separate Copper galacturonate from Copper gluconate?. Answer A172 I suggest trying ZORBAX SAX 70Å 5um, 4.6 x 150mm 820888-901, with water and acetonitrile mobile phase, say 50% to start. Hopefully the two -OH rich compounds will be retained on the quaternary amines of the SAX column, adjust water strength to elute. UV detection (230 nm) should work since they both have a carbonyl. Question Q173 Is there any kind of "generic" column test to track the performance of a column? Answer A173 The best way to evaluate a columns performance is to use the QC test that should be shipped with each HPLC column provided to you. By comparing the efficiency, retention and peak shape of the peaks in the sample and very importantly the pressure under these experimental conditions, you will be able to tell if your column has changed over time. These tests can also tell you how your column has changed, as these are the same tools we use to diagnose a column problem. Significant changes in retention, can suggest loss in bonded phase and significant changes in peak width/efficiency and pressure can suggest column contamination. Dramatic losses in peak width and efficiency suggest a column void. Most manufacturers use similar solutes and mobile phase test conditions to QC their columns. However, different bonded phase require modification of the amount of organic modifier to achieve reasonable retention. What's important is that that you QC-test a column on your system before you use it for a particular project. Then you know how that column performs on your system, before you start injecting samples and before you start having problems. If problems develop, use this QC-test to verify that the HPLC system and the column are performing well. Before you retire a column from a project, clean and QC-test the column. If for any reason, you start a project with a used column, at a minimum, QC-test the column before injecting samples. Question Q174 LC & LC/MS Columns - USP Designations Answer A174 https://www.agilent.com/en-us/support/liquid-chromatography/kb005979 Question Q175 LC Column User Guides Answer A175 https://www.agilent.com/en-us/support/liquid-chromatography/kb005965 Question Q176 My work requires very high sample throughput. How fast can I do a gradient separation? Answer A176 More and more people, especially those who analyze combinatorial chemistry samples, need to analyze a lot of unknown samples quickly. The best way to do this is on short, Rapid Resolution columns with rapid gradient times. The best gradient time is the one that resolves all of your analytes in the least amount of time. On very short columns — 30 and 50 mm lengths — a good starting point would be a 2 - 5 minute gradient. From there optimize your separation for organic range and gradient time. On these short columns you can easily increase the flow rate to further decrease analysis time to 30 seconds without exceeding the pressure limits of the columns. Column re-equilibration times are typically as short as the analysis times — 3 - 5 minutes for the 50 mm columns. Question Q177 Should I just select the Bonus-RP column for all my method development with basic compounds? Answer A177 Basic compounds are best analyzed following the method development scheme outlined earlier in this brochure. Select an SB-C8 or SB-C18 column for initial development and use a buffered low pH mobile phase. Many times this approach provides a good separation and the StableBond columns will have exceptional lifetime at low pH even at high temperatures. Question Q178 Some manufacturers’ indicate (newer) columns can be reversed to remove blockage from the front of the column. Is this generally recommended or does it depend on the column? Answer A178 HPLC columns are more efficient and packed better than years ago, therefore this is generally recommended for most reversed-phase and normal phase silica based columns. This procedure is designed to remove particles from the column frit when high pressure occurs at the column inlet, but it will not work all the time. Because it does not require opening the column it is worth trying. Make sure when you do this that you disconnect the column from the detector and make sure the particles that plugged the column are not coming from the HPLC system or you may just plug the frit at the back end of the column and this may not be replaceable. Columns can also be turned in the reverse direction for washing/cleaning with stronger solvents to remove adsorbed material. This has the benefit of not exposing the rest of the column to the contaminants. When this is done the column should also not be attached to the detector. Question Q179 There are a lot of different column configurations (dimensions) available, but I don’t see the one I’m looking for. Can I get a column made in the configuration I want? Answer A179 Most likely. Agilent is continually adding to its HPLC column offerings, so check with your Agilent column distributor or in the US call Agilent Customer Assist at 800-227-9700 and ask for HPLC column support to find out if the column configuration you need is currently available. For locations outside the U.S., your authorized Agilent column distributor, listed on the Agilent website, can also help you find out the cost and delivery time. If the column is not available, a column can be packed in the configuration of your choice with available bonded-phases. Select an internal diameter and specify a column length, bonded-phase, and particle size using product number 899999-999. A special products quote (SPQ) will then be issued to track your order. Question Q181 Very short narrow-bore columns seem ideal for LC/MS. What bonded phase should I use? Answer A181 LC/MS requires volatile mobile phases and the most suitable buffers are acetate and format. The buffer range for acetate is from pH 3.8 - 5.8 so the best bonded-phases to start with would be the Eclipse XDB C18 and C8. Formate is also widely used and has a buffer range from pH 2.8 - 4.8. When using this buffer you can select StableBond columns then Eclipse XDB columns and follow the same method development scheme as discussed in the method development section. For high pH, using ammonium hydroxide at pH 10.5, select Extend-C18. Question Q182 What are the steps to troubleshoot leak errors? Answer A182 Leak Detected in the 1100/1200 Series Pump (Binary, Quaternary, and Isocratic) The error message Leak Detected on the 1100 Series Pumps is caused when a leak occurs and solvent flows to the sensor. After removing the front door, using the grey press buttons on the sides of the door, the sensor is found on the base of the front of the unit. Suggested Actions: 1. Dry sensor and surrounding area. Note that this sensor is deeper than it appears. Make sure all solvent is removed from the sensor well. Power off the Thermostatted Column Compartment and turn back on to reinitialize. 2. Look for possible areas on the Thermostatted Column Compartment that could be the cause of the leak. Examine the system for loose fittings, broken capillary tubing or a leak from the column switching valve (if installed),. Look for leaks in the module above the Thermostatted Column Compartment and for the presence of solvent in the corrugated waste-tubing which leads to the autosampler. 3. Once the leak is found, correct the problem by tightening the fittings, replacing leaking capillaries, and exchanging defective capillaries. 4. One other possible cause of a Leak error is condensation. Use a higher temperature set point to check for this possibility. Question Q183 What column do you recommend to analyze raw materials? Answer A183 Column choice, and appropriate mobile phase, depends on many characteristics of the sample such as polarity, pKa of ionizable functional groups, solubility vs. pH, and molecular weight. Question Q184 What do you recommend doing when a impurity peak starts to co-elute and actually starts to make itself present in your main peak as a hump to the peak? Answer A184 How much of a change in resolution are you seeing? Has resolution decreased over time or has the separation been disappointing right out of the box? Do you have any information telling you what factors may cause these peaks to converge? Are they sensitive to small changes in temperature, pH or organic composition? Is one compound much larger than the other? These factors and more can be causing the two peaks to merge. More information would be required to specifically answer this question. Question Q185 What do you think about neutralizing extra-column volume by packing short columns with wide-bores (7mm)? Answer A185 As long as you are willing to accept operating at a higher flow rate. If you operate at 1.0 mL/min on a 4.6 mm i.d. column, then operating at 2.3 mL/min would be the equivalent linear velocity when using a 7.0 mm i.d. column. Solvent waste may be an issue. Question Q186 What does the filter do that the guard-column does not? Answer A186 Nothing really - both a filter and a guard can capture small particulates that are either coming from your sample, mobile phase or are from wear-and-tear of instrument seals and gaskets. A guard, on the other hand, traps sample material that is strongly retained on your column, material that would not elute from the column under the experimental conditions defined by the method. These strongly retained materials can build over time at the head of the column and generally lead to high pressure and/or poorly shaped peaks. In some cases, these retained materials cannot be removed even after extensive washings with strong solvent. Question Q187 What does the Flexible Stainless Steel Capillary Tubing Color-Coding Indicate? - 1090 Series LC Answer A187 The color tag on the outside of the Agilent flexible stainless steel tubing indicates the internal diameter (ID) of the tubing: RED indicates an internal diameter of 0.12 mm or 0.005 inches. GREEN indicates an internal diameter of 0.17 mm.or 0.007 inches. BLUE indicates an internal diameter of 0.25 mm or 0.010 inches. ORANGE indicates an internal diameter of 0.50 mm or 0.020 inches Question Q188 What is meant by peak plate? Answer A188 Plates" allow you to compare the efficiency of different columns and its measure is determined by the width of a peak in a chromatogram relative to its retention. In general, for the same retention , the more narrow a peak, the more efficient the column and the more efficient the column has more "plates". HPLC instruments often determine column plates or efficiency by measuring the peak width , typically at half-height, using the following equation:N = efficiency = plates = 5.54(tR/w1/2)2 ,w1/2 = peak width at half-height in min.,tR = retention time in min. The efficiency of a column is reported by the manufacturer of your column and is generally provided in a column report. For a more detailed discussion on how plates and column efficiency relate to resolution and your analyses refer to the text Practical HPLC Method Development written by Lloyd R. Snyder, Joseph J. Kirkland and Joseph L. Glajch, Wiley-Interscience , Second Edition, 1997. Question Q189 What is the purpose of the H3PO4 wash of the column? Answer A189 A phosphoric acid wash has been shown to be effective at reducing tailing caused by the sample complexing with metals in the HPLC system. Typically a 1% phosphoric acid wash of the system and column is suggested to eliminate this tailing and it works. It is perfectly reasonable to use these recommended wash conditions with Agilent ZORBAX StableBond reversed-phase HPLC products. The StableBond HPLC column is particularly stable at low pH - the SB-C18 column is stable at a pH of 0.8 and 90°C. How can you tell if your peak tailing is caused by metal complexation? Look to see if a lone pair of electrons on either a N or O atom can chelate with the metal to form a 5 or 6-membered ring. Metal complexation is a commonly overlooked cause of peak tailing and metals are presents in every HPLC system. Question Q190 What might cause a rhythmic, wavy baseline? Answer A190 This is rarely a column problem. The most common causes of this problem are related to the pumping system. a) If you have an isocratic pump, your pump seals may be worn. Typically your pump will have two pistons and seals. One may be more worn than the other causing flow and pressure variations in a very rhythmic pattern, which will also be seen by the detector. You can confirm a pump seal problem by varying the flow rate. The frequency (in time) of the baseline fluctuations will increase/decrease proportionally to an increase/decrease in the flow rate if the pump seals are worn. The solution is to replace the pump seals. b) If you have a multiple pump system (binary, ternary, or quaternary), the problem may also be pump seals but could also be a function of insufficient mixing or of a malfunctioning proportioning valve. The former can be solved by adding a mixing column (ask your manufacturer for a recommendation) and the latter by a service call. Another possibility is an aging lamp although these signal fluctuations are not as perfectly periodic as a pump problem. An aging lamp can be distinguished from a pump problem with the flow rate experiment described above. If the frequency of signal fluctuations (in time) don't change when the flow rate is varied, the problem may be the lamp. Question Q191 What solvents do you recommend to clean the columns? Answer A191 I generally recommend using the organic solvent acetonitrile to clean reversed-phase, C8 or C18, silica-based HPLC columns. THF is a strong reversed-phase organic solvent and that may be difficult to remove from hydrophobic bonded-phases, causing chromatographic variability. For most situations, acetonitrile is a strong enough solvent to remove sample and mobile phase components that have accumulated on your column during routine isocratic use. Before cleaning the column with organic solvent however, be sure that you have removed any buffer salts that may be in your mobile phase and column to avoid precipitation of these salts in the column. To do that, prepare your mobile phase without buffer salts and flush your column with 15-20 column volumes of this mixture. That is, if your mobile phase is fifty-percent acetonitrile and fifty-percent 50 mM phosphate buffer, then the appropriate first step would be to remove the buffer salts with 50/50 mixture of acetonitrile and water. Then I would suggest flushing the column with pure acetonitrile thoroughly for 30-40 column volumes. If you believe there may particulates at the top of the column, e.g., pressure may be higher than normal, you should consider disconnecting the column from the detector and reversing the direction of flow before the cleaning step. Do no reconnect the column to the detector, but allow the cleaning solvent, in this case, acetonitrile, to collect in a beaker. Since acetonitrile is commonly recommended for long-term column storage, the column can be easily stored after cleaning using the procedure described above. When ready to re-use this stored solvent, remember to flush the column with your mobile phase composition without buffer salts before introducing the buffered mobile phase, again to reduce the possibility of salt precipitation. Question Q192 What temperature should I use for my separation? Answer A192 Temperature control for separations is important for long-term retention reproducibility, one factor of method ruggedness. Controlling temperature at 35 - 40°C is normally sufficient for good method reproducibility and ruggedness. In addition, the use of elevated temperature can have other benefits. First, it reduces the system operating pressure by reducing the viscosity of the mobile phase. Second, it will reduce analysis time, which can substantially increase productivity. Third, temperature may change the selectivity of a separation. Not all compounds have the same response to temperature so the selectivity of a separation can change dramatically when temperature is increased or decreased. StableBond columns have high temperature limits — SB-C18 can be taken up to 90°C, at low pH, and SB-C8 , SB-Phenyl , SB-CN and SB-C3 can be taken up to 80°C, making it possible to optimize your separation without changing columns, particularly if you are analyzing ionizable compounds. Question Q193 What types of column are dissolved above pH 7? Answer A193 Many commercially available silica-based HPLC packings dissolve at pH 7, for the simple reason that silica is soluble at pH 7. Therefore, Agilent has developed technology to significantly reduce silica dissolution and extend the usable pH range of silica-based columns. The ZORBAX Extend-C18 can be effectively used above pH 8 and even up to pH 11.5. Bidentate-bonding is key to this enhanced stability while offering the high efficiency that only silica can provide. Question Q194 What's the best procedure for cleaning out ion pair reagent materials from a column? Answer A194 Some detergents are used as ion-pair (IP) reagents, e.g. SDS with a carbon chain length of twelve. However, most commonly used ion-pair reagents have shorter carbon chains, e.g. hexane sulfonate has carbon chain length of six. IP reagents with longer carbon chains are more difficult to remove from RP-HPLC columns. Studies have shown that ion-pair reagents and some detergents are best removed with long washes with a 50/50: v/v, methanol/water mobile phase system. If you can regain the retention, selectivity and efficiency (resolution) of a known separation (e.g., QC sample) after washing, then you might have successfully removed the ion-pair reagent. I would not recommend using this column for developing a new method as exposure to ion-pair reagents may change the retention characteristics of a column permanently. If scouting runs for a new method are conducted on a column exposed to ion-pair reagents, a new column should be purchased as soon as possible to verify that the selectivity is not different. In my opinion, columns exposed to IP reagents should be dedicated to the ion-pair method. Question Q195 When do you see peak fronting? Answer A195 Peak fronting can occur under a variety of conditions. The most well known is peak fronting that occurs due to column overload. In this case you will typically see the peak retention time shift slightly shorter. This is also the simplest to evaluate, because you can just inject less sample and evaluate the peak shape. But there are at least four other causes of peak fronting. These are column channeling, ionic interactions between the analytes and the silica, poor solubility of the analyte in the mobile phase, and wettability problems between the mobile phase and bonded-phase. A problem with column channeling should result in peak fronting on all peaks or at least the largest peak in the chromatogram if the others are very small. If this occurs you need to replace the column. To evaluate this problem try a new column. Increasing the buffer ionic strength or changing the pH of the mobile phase can often improve ionic interactions, which cause fronting. Increasing the ionic strength can reduce interactions between the silica and ionic analytes and changing the pH can have the same effect. Solubility needs to be assessed by trying to improve the solubility of the analyte and evaluating the resulting chromatogram. For instance, you can increase the time you sonicate your sample and re-inject or dissolve it in a solvent where the sample has good solubility and then dilute and inject in the mobile phase. Also any sample you suspect has a solubility problem should be filtered. You can also mix your sample and mobile phase off-line to see if it is visibly soluble in the mobile phase. Wettability refers to the ability of the mobile phase to fully penetrate the bonded-phase so that analytes interact with all of the bonded-phase. In cases where there is a highly aqueous mobile phase with a C18 column complete wettability may not be achieved. The bonded-phase can fold over on itself. The results may be loss of retention and distortions in peak shape. If you can, increase the amount of organic in the mobile phase and re-evaluate peak shape. If not you may need to consider selecting a column designed for use in very high aqueous mobile phases. These are the typical causes of peak fronting and some solutions Question Q196 When should I select Phenyl bonded-phases? Answer A196 Both SB-Phenyl and Eclipse XDB-Phenyl bonded phases provide unique selectivity and are often a good choice for changing the selectivity for two closely eluting analytes. Phenyl bonded phases are less retentive than C8 bonded-phases so they offer a second option for reducing retention of late eluting hydrophobic compounds and minimizing analysis time Question Q197 Where can I find the LC Column User Guides? Answer A197 http://www.agilent.com/en-us/support/liquid-chromatography/kb005965 Question Q198 Why are there ghost peak In my chromatogram? Answer A198 Possible Causes: 1. Peaks from previous injections 2. Contamination 3. Air in the system 4. Detector noise Possible Solutions: 1. Run blank injections to examine the contaminant peaks. 2. Make sure elution time is sufficient. It may be necessary to flush the column at the end of a run for a longer period of time or with a stronger solvent. 3. Try removing contaminates by reconditioning or replacing the column. Also make sure all mobile phase components are HPLC grade and freshly prepared with no particles observed in the solvent bottles. Filter mobile phase, if needed. 4. Make sure there are no air bubbles in system, use only well degassed solvents. Observe your waste tubing for air bubbles. 5. Observe the baseline with the flow of the pump turned off. If baseline disturbances are seen, these are detector related. Check the lamp of the detector.
LC Pumps
Question Q200 At what interval should the pump seals be replaced? Answer A200 The pump seals should be replaced on a regular basis. It is recommended that each Liquid Chromatograph user set up a preventive maintenance schedule of pump seal changes. This should be based on pump usage and mobile phase composition. Due to their abrasive nature, salt buffers greatly accelerate the wear of both the seals and pistons.Seals should be replaced when there are leaks detected in the pump head below the pistons, when retention times are unstable, or when the system pressure is unstable. Follow the procedure for changing the seals for the type of pump you are maintaining. https://www.agilent.com/cs/library/support/documents/a26181.pdf Question Q201 What are the steps to replace the pump seals? Answer A201 https://www.agilent.com/cs/library/support/documents/a26181.pdf Question Q202 What is the break / wear - in procedure for piston seals? Answer A202 **Note this procedure is for standard seals NOT for normal phase seals. This procedure will damage normal phase seals.When the new seals are installed, the initial "wear in" procedureis still needed. Pump ISOPROPANOL against a backpressure of at least 350 bar for 15-30 minutes. This is best accomplished by using an old column or a flow restrictor.See this attached file for the Seal Wear-In Procedure for 1100 Series LC Pumps. Question Q203 What lubricant should be used on the base of Sapphire Plungers? Answer A203 The part number of the lubricant is 79846-65501. Question Q204 What types of injector rotor seals are available? Answer A204 https://www.agilent.com/cs/library/support/documents/f3984301820.pdf
Sample Preparation
Question Q205 Are any additional accessories or parts included with the purchase of a PPM-48 (p/n 5191-4101)? Answer A205 Yes. The PPM-48 is shipped with: • Waste rack with three waste bins p/n 5191-4112 • Installation kit p/n 5191-4114 • User Manual publication number 5991-8133EN The manifold comes with a sealing gasket already installed. Question Q206 Are any additional accessories or parts included with the purchase of a PPM-96 (p/n 5191-4116)? Answer A206 Yes. The PPM-96 is shipped with: • Single well waste plate p/n 5191-4121 • Holder for plates p/n 5191-4120 • Installation kit p/n 5191-4114 • User Manual publication number 5991-8133EN The manifold comes with a sealing gasket already installed Question Q207 Are there any consumables or parts that I need to regularly order or replace? Answer A207 The only part that needs to be regularly replaced (both units) is the sealing gasket (PPM-48: 5191-4110; PPM-96: 5191-4117). Please note that each processor has its own unique sealing gasket (different p/n- because they are different shapes). Agilent recommends ordering these parts as needed due to adhesive expiration dates. The PPM-48 also uses disposable waste bins (p/n 5191-4113) to collect waste during various sample processing steps. They can be reused (customer's best judgment should be used to determine when they need replacement- depends on solvent(s) used, hazard of the sample/solvent, wear and tear, etc.). The single well waste plate for the PPM-96 (p/n 5191-4121), like the PPM-48 waste bins, is also a consumable, and while it can be reused, it should be replaced as necessary. Question Q208 Does the processor require any maintenance and if so, how often should it be performed? Answer A208 The sealing gasket should be wiped periodically with methanol and a lint free cloth. For simplicity, this can be done after every extraction procedure is completed. The sealing gasket should also be replaced 1-2x per year depending on wear, solvent usage, and overall condition. Instructions for replacement are included with each new sealing gasket and are also found in the user manual (5991-8133EN). If the two sets of instructions differ, use the instructions that are included in the box with the sealing gasket. Wiping of the whole processor can be performed as needed with compatible solvents/water. Question Q209 Does the rotameter help control flow for both Low and High Flow modes? Answer A209 No, the rotameter is only used for fine control for the Low Flow mode. When using Low Flow, the gas will run through low flow regulator and through the rotameter before entering the manifold to allow for more fine control at low pressure. When using High Flow, the gas will run directly from gas supply through the high flow regulator to the manifold. Question Q210 For the PPM-48, which switches correspond to which rows? Answer A210 As you are looking at the top of the manifold, the row furthest in the back (farthest from the front of the processor) will shut off the entire row A. The second switch from the back will shut off row B, and so forth. Therefore, the closest switch as you are looking at the front of the PPM-48 is for row D. The cartridge rack is labeled with Rows A-D. Row A is in the back, moving up to row D in the front. Question Q211 For the PPM-48, which switches correspond to which rows? Answer A211 https://www.agilent.com/en/support/switches Question Q212 For the PPM-48, why does my 1 mL cartridge rack have a black bar in between rows B and C when the other cartridge racks don’t have this bar? It is blocking my view of some of the cartridges. The bar has screws to hold it in place, so can I remove it? Answer A212 NO, you cannot remove this black bar. The bar is intended to provide additional stability to the 1 mL cartridge rack during compression. It is necessary to ensure proper pressure distribution between cartridges 1-12. The black bar sits between rows B and C making it more difficult to view cartridges that are in rows A and B. However, the bottom tips of the cartridges are still visible, and can be used to monitor flow of these rows if desired. Question Q213 How can I disconnect the processor from the nitrogen source? Answer A213 To remove the tubing from the back of the manifold (“gas inlet”), compress the outer ring of the push to connect fitting while simultaneously pulling out the tubing. Question Q214 How do I set the pressure for the processor? Answer A214 The processor has locking regulator knobs, one for Low Flow and another for High Flow. Pull out knob. Turn clockwise to increase pressure. Turn counter-clockwise to decrease pressure. When desired pressure is achieved, push knob in to "lock" pressure. It is easier to monitor/set the pressure when the flow rate selector is set to Low Flow or High Flow and the gas source is turned on. Question Q215 How do I set the pressure for the processor? Answer A215 https://www.agilent.com/en/support/set-pressure Question Q216 How do I use Captiva Syringe Filters? Answer A216 ??https://www.agilent.com/en/products/sample-preparation/sample-preparation-methods/filtration/stepbystep Question Q217 How frequently should I replace the manifold gasket on the processor? Answer A217 We recommended replacing them at least once a year for PM purposes. Under heavy use you might need to replace them once to 3 times per year depending on usage. We recommend daily inspections of the column seal for any signs of wear and recommend replacing if there are any visual signs of rip or tears as well as the column seal peeling off of the manifold. Question Q218 How frequently should I replace the manifold gasket on the processor? Answer A218 https://www.agilent.com/en/support/gasket Question Q219 How often should I replace my BHT-2 or BHT-4 gas filter? Answer A219 BHT-2 and BHT-4 traps are designed to filter 13 standard cylinders of gas. If you are unsure of the gas input quantity, a replacement interval of 1 year is recommended. Depending on usage, the filter can last up to 2 years. Question Q220 I can’t remove the back tubing on the positive pressure regulator, even when I follow the appropriate instructions. Answer A220 Sometimes the outer ring of the push to connect fittings can be dislodged. This may (but not always) be obvious visually, and will look like the outer ring is sticking out way more than the outer ring on a different push to connect fitting. One of the main causes of this dislodgment is trying to remove the tubing without pushing the outer ring in. Try re-seating the outer ring into the push to connect fitting with a pair of plyers by simply pushing the outer ring into the fitting (the tubing should be still connected- do not pull on the tubing while you are doing this). Once the push to connect fitting has been reseated, you should be able to push on the outer ring and simultaneously pull out the tubing. Question Q221 I see a pressure drop for High Flow pressure when I turn the flow selector from Off to High Flow. Is this normal? Answer A221 Yes, it can be. When the processor is in Off mode, there is no gas flowing through the system which can cause a slight back pressure to occur. When the flow selector is set to High Flow the gauge will immediately display the pressure that is currently being applied to the processor. For the PPM-48, with each row that is turned on via the row switches, there may be a slight decrease in the observed pressure in the high flow gauge. For example, if the high flow pressure is set to 80 psi with no rows on, the pressure will read 80 psi. As each row is turned on you may experience a 1-3 psi drop in pressure (if you are looking at the gauge). This is normal. However, if you are experiencing a much higher drop in pressure as row switches are turned on, it is most likely due to your input gas supply not meeting the minimum required pressure for the processor. Question Q222 I see a weird flow pattern when I am using 1 mL cartridges with my PPM-48. The end cartridges (columns 1-2 and 11-12) flow faster than the middle cartridges (3-10). Answer A222 Ensure that the 1 mL cartridge rack has the black stability bar installed and that it has not been removed. Without the stability bar, the cartridge rack may not compress correctly which can lead to inconsistent or variable pressure differences across the row. Question Q223 I’m struggling to remove the white paper backing of a new replacement sealing gasket. Answer A223 If the white paper backing of the replacement sealing gasket is difficult to remove- STOP immediately. One reason for the trouble may be because the adhesive is actually sticking to the paper backing and is being removed from the seal as you pull the backing off. The white backing when removed should be very smooth to the touch, and not sticky at all. You can use tweezers to help start to peel the backing off. Try a corner first, but if you are still having trouble, sometimes starting from the middle of the sealing gasket may work better. Question Q224 My sealing gasket won’t stick to the manifold. Answer A224 If the sealing gasket is old and currently installed: Replace the seal. If the replacement sealing gasket is not sticking initially: Ensure that all old adhesive has been removed from the manifold prior to attempting to attach a new sealing gasket. Old adhesive can be removed with acetone and/or isopropanol. A lint-free cloth should be used to prevent contamination to any of the manifold air holes. Avoid getting old adhesive into the manifold holes. If you notice adhesive in the holes, use small tweezers or similar item to remove all adhesive. Ensure that the white backing has been removed from the sealing gasket. The backing should remove clean (i.e. no adhesive residue should be on the backing). The back of the sealing gasket should feel sticky. Check to ensure that the adhesive remains on the sealing gasket as sometimes, the adhesive can be removed with the backing, rendering the sealing gasket not sticky! Press firmly to ensure the sealing gasket is attached. Follow specific instructions provided with the sealing gasket or in the manual to ensure proper installation. Question Q225 What are the recommended pressures for Low Flow and High Flow? Answer A225 Low Flow starting pressure recommendation is 3-4 psi, with the rotameter almost, but not fully, closed. If using High Flow for drying steps, any pressure between 50-80 psi is acceptable. Pressures can be set lower for High Flow for eluting more viscous samples. There is no pressure recommendation for this scenario as it will be sample dependent. Question Q226 What are the recommended pressures for Low Flow and High Flow? Answer A226 https://www.agilent.com/en/support/recommended-pressures Question Q227 What happens if I accidently lower or raise the manifold with the gas flow on (set to Low or High flow)? Answer A227 It is recommended to set the flow rate selector to Off when you are going to raise or lower the manifold. Movement of the manifold requires gas (it is all pneumatic). If you have the flow rate selector turned to Low Flow or High Flow then gas will be flowing through the manifold already. This is gas that is now not available to raise or lower the manifold. Therefore, to ensure enough gas is available to lower or raise the manifold, the flow rate selector should be set to Off during every compression/decompression step. Question Q228 What if I am using a harsh solvent in my sample preparation procedure? Answer A228 First, ensure that you have your processor installed in a location with proper ventilation, such as a fume hood, as dictated by the hazards of the solvent(s) being used. Also, ensure that appropriate personal protective equipment (PPE) such as gloves, googles, lab coat etc. are used according to the hazards. Regarding the effect of the harsh solvent on the processor, ensure that if any of the solvent spills on the processor or any of its components/accessories, it is wiped up immediately. Dispose of the waste and clean-up materials as dictated by the hazard and/or your laboratory protocols. It is especially important to wipe up any solvent that is on the cartridge rack, cartridges, or 96-well plate prior to compression. Prolonged exposure to solvent can damage the sealing gasket, so all efforts should be made to prevent direct contact with any solvents. Unnecessary, prolonged contact of the manifold (sealing gasket) and cartridge rack or 96-well plate should be avoided. Compression should occur only as dictated by the sample preparation method. Question Q229 What if I don’t have access to compressed nitrogen? Answer A229 The processor can operate using high purity filtered instrument air. Question Q230 What if I don’t have access to compressed nitrogen? Answer A230 https://www.agilent.com/en/support/n2 Question Q231 What is the charge capacity for SampliQ SCX 5982-3267? Answer A231 Our Polymeric SCX averages ~1,000 umol/g based on both elemental analysis and breakthrough method Question Q232 What is the rotameter and how do I use it? Answer A232 The rotameter is a device that measures the flow rate of a fluid or gas (in the case of the PPM it is measuring the GAS flow rate). The units for the rotameter are SCFH- standard cubic feet per hour- and will measure from 0-2.5 SCFH. The rotameter is only used with the Low Flow setting. Turning the rotameter knob counter clockwise will open the valve. Turning the knob clockwise will close/shut off the rotameter.DO NOT SHUT OFF THE ROTAMETER. Anytime the rotameter needs to be turned down/closed more, it is important to turn clockwise while ensuring you never fully close the valve. As soon as you feel any resistance, stop. It is a good idea to perform a slight counter turn to ensure it is not closed. Permanent damage can occur to the rotameter if the knob is closed regardless of whether the gas flow is on. Again, the rotameter should never be shut off regardless of gas flow being on or off. It is generally good practice to monitor the flows for the fastest flowing cartridges/wells and adjust pressure accordingly to ensure they are at the right level. As those cartridges/wells finish eluting, the rotameter can be opened more to allow more pressure to reach the slower flowing cartridges/wells. Question Q233 What other parts or accessories do I need to order with my PPM-48? Answer A233 Regardless of sample preparation technique, a cartridge rack(s) will need to be purchased (3 options). Cartridge racks: 1 mL cartridge rack p/n 5191-4102 3 mL cartridge rack p/n 5191-4103 6 mL cartridge rack p/n 5191-4104 A collection rack(s) (to hold test tubes or autosampler vials) will also be necessary. Collection racks: 10 × 75 mm tubes p/n 5191-4105 12 × 75 mm tubes p/n 5191-4106 13 × 100 mm tubes p/n 5191-4107 16 × 100 mm tubes p/n 5191-4108 12 × 32 mm autosampler vials p/n 5191-4109 If you are doing SPE, then you most likely have all or some of the following steps PRIOR to elution in which you will not want to collect the eluting liquid: conditioning, equilibration, loading, washing. Unless you wish to collect the liquid from these steps, then a waste rack with waste bin will be very useful. The waste rack and a 3/pk of bins are included with the initial purchase of a PPM-48; however, additional waste bins (3/pk: p/n 5191-4113) may be purchased. It is recommended that you use a gas filter to filter your gas supply. A BHT-4 (1/4 fittings) or BHT-2 (1/8 inch fittings) are available from Agilent. Sealing gasket is a consumable that will need to be replaced (1-2x per year), however Agilent doesn't recommend ordering this at the same time as the processor order due to the expiration of the sealing gasket adhesive. Question Q234 What other parts or accessories do I need to order with my PPM-96? Answer A234 Most of the accessories/parts that you will need with the PPM-96 will just be the sample preparation 96-well plate and 96-well collection plate you require for your method. The single well waste plate that is provided with the initial processor order can be reused, but additional can also be purchased as necessary (p/n 5191-4121). If you are planning on using the PPM-96 for tables 1 mL cartridges, a 1mL tables cartridge holder is required (p/n 5191-4119). The sealing gasket is a consumable that will need to be replaced (1-2x per year), however Agilent doesn't recommend ordering this at the same time as the processor order due to the expiration of the sealing gasket adhesive. It is also recommended that you only order as needed, and do not keep lot of spares on hand due to the expiration of the sealing gasket adhesive. Question Q235 What size frits are used in the SampliQ products? Answer A235 The pore size of the frits is 20um. More SampliQ-specific FAQs and answers can be found in the attached document. Question Q236 When I first turn on the flow (Off to Low Flow) I get a large burst of pressure which makes my samples elute at an undesirable rate for the first few seconds. How can I prevent this? Answer A236 This "burst" is usually due to backpressure build up from a period of processor inactivity. A slight build-up is normal. To avoid this, you can "prime" the processor. If using Low Flow mode, simply turn the flow selector from Off to Low Flow prior to compression of the manifold for 2-3 seconds or until pressure stabilizes and returns to original setting. Ensure that the flow selector is returned to Off prior to compression. If using High Flow mode, the same procedure can be followed with the flow selector set to High Flow. However, usually this difference in High Flow is nominal since the pressure is already so high. AKA- the difference between 3 and 5 psi (Low Flow) can be substantial for your samples, when the difference between 80 and 83 psi (High Flow) generally won't significantly affect the flow rates of the cartridges. Question Q237 When I turn on my gas supply source, the processor pressure gauges don’t register any pressure. Answer A237 Disconnect the gas supply tubing from the processor. Turn on the gas supply source and ensure there is flow coming from the installed gas supply tubing. Turn off the gas supply. Insert the tubing by pushing it into right-hand port ("Gas Inlet") of the processor (when looking at the back of the unit). When the tubing is installed properly, you should not be able to pull it out of the port. Then turn on the nitrogen source. Question Q238 Where can I find the QuEChERS SOP (Standard Operating Procedures)? Answer A238 We have a recommended SOP that can be followed using the AOAC 2007.01 and the EN Method 15662 kits. Question Q239 Why can’t I compress/lower the manifold? Answer A239 Ensure the nitrogen source is turned on, and the flow rate selector is set to Off. Ensure the processor is receiving adequate gas (60-100 psi) by checking the pressure gauges on the unit. If you are still unsure of the pressure or if the processor is receiving gas, use a pressure gauge/regulator with your gas supply to monitor. Both compression switches must be pressed and held simultaneously to lower or raise the manifold. If you let go of the switches too early, the manifold will raise back up. This in an intentional safety feature. The manifold will stop when it reaches the cartridge or plate stack. Make sure you hold down the switches until this contact has been made. It doesn't hurt the processor to hold the switches for an extra second or two after compression to ensure the manifold is compressed. Question Q240 With what gas supply pressure(s) is the processor compatible? Answer A240 The processor can operate with input pressures between 60 psi (minimum) and 100 psi (maximum). Optimum source pressure is 80 psi. If you are unsure of the pressure of your in-house gas, it is highly recommended that a supply gas pressure gauge and/or regulator is installed.
Syringes and Sample Introduction
Question Q241 Do econofilter syringe filters come with a certificate? Answer A241 No. Certificates are not available for econoline vials. Question Q242 How do I choose the right syringe filter for my application? Answer A242 https://filtrationselectiontool.chem.agilent.com/product-guide/agilent-filters-product-guide/ Question Q243 How do I find needle gauge dimensions of a manual syringe? Answer A243 https://www.agilent.com/en-us/products/lab-supplies/chromatography-spectroscopy/more-information Question Q244 Syringe selection guide Answer A244 https://www.agilent.com/search/gn/syringe-selector?searchTermRedirect=Syringe%20selection%20guide Question Q245 What are the steps to change the sample needle? Answer A245 https://www.agilent.com/cs/library/support/documents/a16176.pdf Question Q246 What does the diameter of the filter refer to? Answer A246 The diameter of the filter refers to the active membrane diameter, not the filter body. Question Q247 What ships with the Color Coded Manual Syringes?: Answer A247 The Manual Syringes ship with an insert that describe how to use the packaging as a syringe holder and general care and use instructions. It also provides instructions for getting the Certificate of Conformance. Question Q248 What syringe offerings does Agilent have? Answer A248 https://www.agilent.com/en-us/products/lab-supplies/chromatography-spectroscopy/syringes#1 Question Q249 What types of gas chromatography syringes are available? Answer A249 https://www.agilent.com/cs/library/support/documents/FAQ381%20F03021.pdf Question Q250 Will the syringe filters work with any manufacturer's syringe? Answer A250 The syringe filter has a standard luer connection that should fit any syringe using a standard luer connection.
Tools, Fittings, Capillaries, Tubing, and Supplies
Question Q251 Can an oil free Rough pump be used With a Diffusion pump MS? Answer A251 Oil Free Rough Pumps are not compatible with diffusion pump MSD. Oil mist from the Diff pump might reach the scroll heads of the Dry Scroll pump or membranes on Diaphragm pumps and reduce drastically their performance. Question Q252 How are the Markes Difflock caps (MKI-MTD-1204) packaged and what color are they? Answer A252 The caps are supplied in packages of 10. They have an inert coating which gives them a unique color/appearance. Question Q253 The UI gold seal has spots – is it used, or rusty? Answer A253 The UI gold seal has spots – is it used, or rusty? Due to the Ultra Inert deactivation process, there may be slight variation in the visual appearance of the Ultra Inert treated gold seals. The surface of the Ultra Inert gold seal has a matted appearance in place of the shiny surface seen on untreated gold seals. The presence of spots or darker colored areas on the surface of the Ultra Inert gold seal are normal side effects of the deactivation process, and not due to contamination or faulty processing. These spots do not affect the performance or inertness of the seal. Question Q254 UltiMetal Plus Flexible Metal Ferrule Answer A254 https://www.agilent.com/en-us/support/gas-chromatography/kb005973 Question Q255 What is the Gold-seal with the cross used for? Answer A255 https://www.agilent.com/cs/library/usermanuals/public/Tips%20Tricks%20of%20Injector%20Maintenance_012810.zip Question Q257 What tool should I use for cutting fused silica columns? Answer A257 https://www.agilent.com/en-us/products/gas-chromatography/gc-columns/capillary-tubing-accessories/fused-silica-tubing-cutters Question Q258 What traps are available for the Purge and Trap device? Answer A258 Information can be found in the consumables catalog under Teledyne Tekmar Purge and Trap supplies https://www.agilent.com/cs/library/catalogs/public/5991-5213EN_GC_Catalog_Supply.pdf Question Q259 What tubes and accessories are available for the Markes Thermal Desorption system? Answer A259 Information can be found in the consumables catalog under Markes Thermal Desorptionhttp://www.agilent.com/cs/library/catalogs/public/5991-5213EN_GC_Catalog_Supply.pdf Question Q260 Where can I find information about Ultimate Unions? Answer A260 https://www.agilent.com/en-us/products/gas-chromatography/gc-supplies/ferrules-connectors/ultimate-union
Vials and Closures
Question Q261 Can I use septa on the HPLC vials and test tubes when using… Answer A261 Can I use septa on the HPLC vials and test tubes when using the 8000? Yes. Use pre-slit septa, as these will greatly prolong the life of the 8000 Dissolution Sampling Station needles. If needle puncture marks begin to move away from the center of the septa, this indicates that the needle is dulling and should be replaced to avoid damage to the 8000 and ensure proper sample delivery. Should you need assistance with this or any other Agilent Dissolution Systems product, contact Agilent’s Technical Support team at +1-800-227-9770, select option 3, and then option 2, to be connected to the correct assistance team member. You may also contact our Dissolution Hotline at dissolution.hotline@agilent.com. Question Q262 How much can a sample vial be filled? Answer A262 Place samples for headspace extraction in glass vials. Place the glass vials in the Headspace Sampler tray. In general, fill sample vials about half way (although vials can be filled to the 3/4 level). This ensures that the sampling probe will not come into contact with the solid or liquid phase during the sampling step. The G1888 Network Headspace Sampler accepts either 10-mL or 20-mL sample vials. The Headspace Sampler can only run one vial size at a time. The vial must be sealed properly to insure that the headspace gases do not escape prematurely. For crimp top vials, use a crimper (Agilent part no. 9301–0720) designed for headspace vials with 20-mm caps to seal the vials. Screw caps (Agilent part no. 5188–2759) and screw top vials (Agilent part no. 5188–2753) are also available. See Headspace Consumables FAQ for more information. Sampling from an incorrectly capped vial may cause the Headspace Sampler to jam during septum puncture. Do the following to prepare a vial for sampling: 1. Place a septum in a vial cap with the PTFE side facing the vial. Take care not to contaminate the septum. 2. Place the cap upside down on a table. 3. Place the sample in the vial. Most vial should not be more than 50% full, but some vials can reach 75% full. 4. Place the septum and cap together over the vial opening. 5. Place the crimper over the cap and vial. See Figure14. 6. With slow and steady pressure, squeeze the crimper handles to seal the vial. 7. Remove the crimper. 8. Turn the vial and cap 90° and crimp a second time. 9. Check that the seal is adequate by trying to twist the cap on the vial. It should be difficult or impossible to turn the cap. If the cap turns easily, recrimp the cap. The crimping tool may need adjustment. 10. To decap vials, use a decapper for vials with 20-mm caps (part no. 5181–1214). Vials will contain laboratory air, which may be contaminated with things such as solvents or freon leaking from air conditioners. If contaminants will adversely affect your results, use argon to purge the vials just before capping and sealing. Question Q263 What are 'Certified’ consumables? Answer A263 Agilent Certified consumables come with a certificate of analysis, so you can be sure that they will perform even in the most demanding environments.