Cannot find the transition in GC/QQQ at a known Ret.time
Posted: Sat Apr 15, 2023 1:10 am
Hello everyone,
I would like to know if someone has experienced the same problem I have working in MS/MS (product ions mode) using GC/QQQ. I am working with an Agilent GC 7890A/MS triple Quad 7000A, with the collision cell at 45 eV mode to get the product ions of a selected parent ion (m/z 173 of a BSTFA derivatized compound). I can perfectly see the m/z 173, but when I work in MS/MS mode, the peak in the chromatogram corresponding to the transition 173 -> ** disappears at the retention time where I see the peak in MS mode (thus, I cannot click on it to obtain the product ions spectra). I am using Mass Hunter version 10.
I know it is not a problem with the equipment because I can see the peak in the chromatogram corresponding to other transitions, and I can indeed see peaks of the transition 173 -> ** at other retention times. There is noise in the baseline, so the MS is physically working at that retention time.
I thought that maybe the collision energy is not enough, and I increased it to 60 eV (the maximum), but I still cannot see the transition. If I cannot see it at 60 eV, I assume that increasing the pressure of the collision gas won't help. I have never had this problem so far and I am not sure what else I can do.
Has someone experienced the same problem? Any tip would be highly appreciated.
Thank you very much!
Best regards,
Joana Pico
I would like to know if someone has experienced the same problem I have working in MS/MS (product ions mode) using GC/QQQ. I am working with an Agilent GC 7890A/MS triple Quad 7000A, with the collision cell at 45 eV mode to get the product ions of a selected parent ion (m/z 173 of a BSTFA derivatized compound). I can perfectly see the m/z 173, but when I work in MS/MS mode, the peak in the chromatogram corresponding to the transition 173 -> ** disappears at the retention time where I see the peak in MS mode (thus, I cannot click on it to obtain the product ions spectra). I am using Mass Hunter version 10.
I know it is not a problem with the equipment because I can see the peak in the chromatogram corresponding to other transitions, and I can indeed see peaks of the transition 173 -> ** at other retention times. There is noise in the baseline, so the MS is physically working at that retention time.
I thought that maybe the collision energy is not enough, and I increased it to 60 eV (the maximum), but I still cannot see the transition. If I cannot see it at 60 eV, I assume that increasing the pressure of the collision gas won't help. I have never had this problem so far and I am not sure what else I can do.
Has someone experienced the same problem? Any tip would be highly appreciated.
Thank you very much!
Best regards,
Joana Pico