7010/8890 HES System - MS1 Abundances low (6-8 million) - poor isotope peak resolution / peak shape in tune - lowering sensitivity

Hello GCMSTQ Friends!

My lab had purchased a 8890/7010 system with HES source (via 3rd party) a few months ago for low level pesticide analysis in cannabis. Previously we have been working with a 7890/7000C with Xtr EI Source for the last few years. Every since we have begun using the 7010 with HES, I have felt there is some issue with MS1 ion abundances, in turn lowering overall sensitivity depending on the tune applied. I am used to 6-10 million counts for PTBFA 69 in my tunes on the 7000C, but was expecting at least double that with the HES. 

Peak shape of tune ions in MS1 are a bit off shaped, and isotope "foot" resolution is not baseline resolved as it appears to be in MS2 (also relative abundances seem low, particularly in mid and high masses). I have opened profile screening in manual tune to live monitor both MS1 and MS2, and am seeing about 1/3 ion abundances in MS1 as MS2. Is this normal? Should both profile abundances be equal? I have attached 2 versions of tune files, one month apart. I have tried tuning from default a number of times with minimal improvements. In addition, we do have hydrogen jetclean installed on this instrument, so I am pretty sure its not a dirty source.

Could MS1 quads be dirty causing this issue?

I would greatly appreciate any and all feedback, Thanks!

Parents
  • What is the serial number on that MS?  Please share a picture of the serial number label....The one listed on the tune report is invalid.

    How many runs on the system?      8890 and Intuvo: Service Mode, Instrument, Usage

    The Tune PFTBA counts do not have anything to do with the ion source type. The tune algorithm has targets to achieve and as long as 69 is big enough, it is acceptable. The tune EMV is fabulous at 989V and the max gain is good at 42052.  What version of MassHunter Acquisition is installed? 

    MS1 abundances are less than MS2 abundances for a couple of reasons but yes, that's normal.

    JetClean only cleans the parts of the ion source that have hydrogen and electrons on them at the same time, so it does not clean PE1, PE2, Ion Focus, and Entrance lens. It does not clean the extractor lens insulator nor the transferline tip seal both of which should be replaced quite frequently.  Clean the source. Replace the filament, extractor lens insulator, lens stack insulator, and tip seal.  Make sure that the column is not installed too far out of the transferline - I like flush with the end of the tipseal ceramic. When the system is vented and the analyzer door is open to remove the source, take pictures of the source parts disassembled, a picture down inside the source radiator of the quad end cap ceramic, and of the front of the collision cell and share those photos, too.

    The tune at 300° C ion source temperature will have lower 219 and 502 relative abundances than with the temperature at 230° C.  That's not a bad thing on a QQQ system and the HES seems to do very well at 300° C.

    The default collision cell gas flows for a 7010x are 4.0 ml/min of quench helium and 1.5 ml/min of collision nitrogen. 2.25/1.5 are the 7000x defaults. The additional helium metastables created in the HES can cause higher detector noise and the additional quench flow reduces that.

    Column flow 1.4 into the HES is the maximum that I would ever recommend. Higher flows change the spectral tilt on the HES quicker than on the orthogonal source.   

    The Q1 DIP value at 1000 is 66.3% which is a first indication that the quad is probably OK - - but that does not tell you if it's dirty necessarily. 

    Fix the air leak.  8.13% nitrogen and 2.18% oxygen is not great. It could be that the high helium carrier gas flow is making this artificially high, so first:  Try reducing the temp to 230, column one flow to 1.05 ml/min and column 2 flow to 1.2, CC gases to 4.0/1.5, and tune again then share that report.

    To recap. Fix the leak. Clean the source. Replace the consumables. Take pictures.

  • Paul, Thanks so much for your detailed reply.

    I have attached pictures of the MS serial sticker, and front enclosure. Unfortunately, the 8890 we have was not originally paired with this MS (it was brand new, the MS was not) so it is hard to know how many runs it has seen. Masshunter Acquisition Version 10.0 Service Release 1, Build 10.0.384.1 is what is currently installed. 

    Within the past 3 months we have replaced the filament, extractor lens insulator, & lens stack insulator. We have not yet replaced the tip seal, and will have one ordered this week to replace it when we clean the source. I was not able to vent last week due to samples, but will follow suit with pictures of everything once I do. 

    Regarding the collision gas/quench flow rates, the software does seem to default to the 2.25/1.5 settings (I was unaware/nearly every Agilent application note that  I have regarding pesticide methods reference the lower flow settings, even when stating 7010x series). Is there detriment in terms of reproducibility in running the lower flow? Should I switch immediately to the 4.0/1.5?

    I have also attached two tune files with the air leak resolved,  one with the column flow settings, temps, and CC gases adjusted as your requested. MS1 looks about the same to me. Thanks again for your help!

     

Reply
  • Paul, Thanks so much for your detailed reply.

    I have attached pictures of the MS serial sticker, and front enclosure. Unfortunately, the 8890 we have was not originally paired with this MS (it was brand new, the MS was not) so it is hard to know how many runs it has seen. Masshunter Acquisition Version 10.0 Service Release 1, Build 10.0.384.1 is what is currently installed. 

    Within the past 3 months we have replaced the filament, extractor lens insulator, & lens stack insulator. We have not yet replaced the tip seal, and will have one ordered this week to replace it when we clean the source. I was not able to vent last week due to samples, but will follow suit with pictures of everything once I do. 

    Regarding the collision gas/quench flow rates, the software does seem to default to the 2.25/1.5 settings (I was unaware/nearly every Agilent application note that  I have regarding pesticide methods reference the lower flow settings, even when stating 7010x series). Is there detriment in terms of reproducibility in running the lower flow? Should I switch immediately to the 4.0/1.5?

    I have also attached two tune files with the air leak resolved,  one with the column flow settings, temps, and CC gases adjusted as your requested. MS1 looks about the same to me. Thanks again for your help!

     

Children
  • That instrument mainframe started life as a 7000B In November 2010. It has no history of being upgraded to the HES.  I wonder when, where, and how that occurred?  If the front analyzer was not replaced in its entirety that could mean that quad 1 could have more than 13 years' worth of use. 

    The 2.25/1.5 CC flows versus 4.0/1.5.  The HES makes more helium metastables and the noise that they create at the detector end is minimized by 4.0 ml/min of helium quench gas in the CC.  Many/most methods were created using a 7000x system and the collision energies developed with the 2.25/1.5 CC flows. A 7010 would benefit by the reduced noise using 4.0/1.5, but the collision energies would have to be adjusted to account for the flow differences.  Few go to those lengths as the sensitivity is so amazing with the HES that the additional noise is not significant.

    The air leak probably contaminated the source, so let's see what happens after the source is cleaned and the parts replaced.  When you have the ion source removed, take a picture inside to show the quad end cap ceramic and the quad if you can.  

  • Wow, very interesting. That would explain some things! This was sold to our owner as a 7010B with no disclaimers regarding conversions or upgrade. With this knowledge, I suppose we cant even be sure the serial number on the enclosure matches the rest of its guts, since it has a 7010 faceplate slapped on it. I cleaned the source with all of the pictures you requested attached below. To my surprise it was way dirtier than I would have expected given the jetclean is installed (wondering if that is even working properly, or at all based on the condition of the repeller and lenses?) 

    Today we actually vented and pulled out the MS1 Analyzer to take a look best we could at the condition of the quads (only viewed from the end opposite the source...didn't want to open the source cap end.. They surely appear worn, and either residue laden, or the gold foil is smudging into itself in some areas. a small 4mm piece of gold actually fell out when we tilted to chamber (no bumping it, it just fell as if it was sitting in there). It was quite difficult to get a good picture of the quads themselves.

    After cleaning the source thoroughly, replacing the tip seal ceramic (column flush with it on), and adjusting the CC flows, the tune did not appear much different. Due to the poor isotope resolution, it is a roll of the dice when it can find the right M+1 values for mid and high masses. Also tune ion abundances seem to keep going down? now 3.75 million for 69 after the cleaning (from 5.5-6 million before, have seen as high as 10 million in the past). I would love a better understanding of what to expect out of this parameter. 

    We are heavily depending on this instrument to be fully functional within the next couple weeks, as our updated state pesticide list and limits are live as of July 1st. Our calibration levels ranging from 0.050-32 ppb.

    Thanks so much for your insight and expertise. 

  • On the front analyzer should be a serial number sticker. Your gold quad picture is beautiful, but unclear. The gold looks almost like bubbling/flaking gold leaf on an antique picture frame.  Is that how it looked?   Also all visible contamination would be at the ion source end.  A piece of gold fell out ?  That is surely not good at all no matter where it fell from.

    From the source end showing contamination.

    I'm not overly concerned about tune ion abundance. As long as it is high enough it will change with every tune as the algorithm adjusts everything every time and the different variables intersect differently.   I understand your worry on the Q1 tune ion peak shapes.

    The extractor lens ceramic is typically a grey/white. The dark ring means it needs to be replaced.

    The front of the collision cell is beautifully clean. The Q1 quad contact ceramics in that picture look pretty good but that's difficult to truly tell. 

    The lenses are the older versions with a ball bearing pressed into opposite sides. The current ones have one bearing for location and a step for contact. 

    The entrance lens has been changed to a longer snout. That is not visible in your photo.  

    JetClean running properly should clean the front of the repeller - the side opposite where the filament sits, the ionization chamber in the source body, and the face of the extractor. In the HES, Post Extractor 1 & 2, the Ion Focus, and the Entrance Lens will not be cleaned as efficiently as those parts.

  • Is this helpful? Apologies for the poor video, but yes almost like an antique gold frame. Appears almost like bubbling rust staining, or sign of delamination of the foil. Again, we didn’t take off the cap to inspect the source end, but I imagine it should be worse.

    regarding the extractor lens insulator…we recently replaced the one pictured with a new Agilent part (~4 months ago) and I was surprised to see it had those dark flecks staining it when I was cleaning. Seems pretty quick for it to get so dirty?


    Thanks again!!


  • That video is a bit hard to see. There's no visual evidence of overheating nor staining on the rest of the analyzer/quad radiator. The factory gold is not a separate applied foil.  That needs further investigation.  I would recommend contacting Agilent for an onsite service call.  Contact Us | Agilent

    When cleaning the ion source, axial or orthogonal, one place that must be cleaned/scrubbed/rinsed is in the ion source body where the extractor insulator sits. If that area is not cleaned or there is still residue from the cleaning it could contaminate that insulator quickly.  The ionization chamber in the body needs to be very clean with no residue as well. After those the only place that type of stuff comes from is column degradation/residue. The air leak you had may have resulted in that problem. Was the column replaced at the same time as the source was cleaned?

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