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Hello,   I wonder if I can use a pre-run command/macro to be executed in chemstation C.01.07 "Run time Checklist", for on/off activation of an external valve? I want to flush gas sample tubings as well as the loop on a gas sampling valve with proper amount af sample gas from a tedlar bag before injection, using a mirco pump connected as an… (Show more)
in Gas Chromatography
Click to view contentHi All,   After I doing maintenance for our GC/MS (EI source), I ran the tune, it shows this problem. I have re-cleaned the EI source, checked all the cable to ensure they were in the right place, checked the column inserted into the MS to ensure it was not inserted too far into the MS.   After doing all of that, I tuned the GC/MS again and… (Show more)
in Gas Chromatography
Hi there, I have a trouble with my GC, when I put the split condition 1:10 the total flow does not go up to 112,5mL/min and falls to 20mL/min. The screen on GC shows this message "SHUTDOWN (# 6) : Back inlet: flow shutdown".
in Gas Chromatography
Dear All,   I analysed samples and standards with GC-7890b for CH4, N2O and CO2. I could see the peaks for each gas in each sample during running and everything was normal. When the work of machine has been finished, I checked the result out, I can't see peaks and I saw this message for each sample: Warning: calibrated compound not found! Could… (Show more)
in Gas Chromatography
Hello, I had a question about measuring temperatures on a 7697A Headspace autosampler. In particular, what type of temperature probe and where would the probe go to measure temperatures at the transferline and sample loop?
in Gas Chromatography
We have microGC in the lab, equipped with Buckflush Column module  20 m MS5 (Channel 1) and Column module 10m PPU  (Channel 2).   As carrier gases Ar and He are used, respectively in Ch 1 and Ch 2.  I have problem  to get GC „ready“. Strange thing is, in some days it works properly, some other days not. After loading the method and waiting for… (Show more)
in Gas Chromatography
Dear all,   Did anyone had any air leak issues related to the Intuvo 9000 system? In particular with the flow path?   Because we are having an air leak issue and also a high amount of nitrogen due of it. So we are trying to find where the air leak is but we are not able to find where the issue that is causing the leak itself.   Kind regards,… (Show more)
in Gas Chromatography
I am operating a 7890/5975 with a Tekmar Atomx XYZ interfaced to the front inlet. The septum purge actual flow reads -11 ml/m when the setpoint is off and about -1 psi when the setpoint is 3.0 ml/m. The inlet has a Merlin Microseal but the same thing happens with an Agilent 5183-4757 septum. I have replaced the inlet liner and O-ring. The weldment… (Show more)
in Gas Chromatography
I have an Agilent 7890A GC-FID with dual split/splitless inlets and detectors configured with a 0.53 mm ID capillary column. My instrument keeps giving me the message "front inlet pressure, system shutdown".  The front inlet cannot maintain pressure and the unit shuts down. On start up the front inlet pressure does reach the setpoint (5.96 psi),… (Show more)
in Gas Chromatography
Hello Guys,   I am using Agilent 7890a GC with an FID detector. Last week I saw that there are few ghost peaks in my chromatogram, so I decided to bakeout the column. After baking the ghost peaks disappeared  but now I see and increase in the peak towards the end of the run (please refer to the attached picture). I cleaned the liner, even put a… (Show more)
in Gas Chromatography
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