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

MisterPinene

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!

  • 0 in reply to MisterPinene

    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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