Agilent SAT GCMS Problems
Posted: Thu Oct 01, 2020 2:16 pm
I have couple of issues that are facing recently in Agilent Saturate GCMS (GC7890B MS59771). Here are the details of these problems:
1) Retention time shift between the samples in the same batch. (As usual we run the standard after checking the tune & the blank, then we adjust the retention time of the reference peak in the standard, then we run a batch of 10 samples, we found all the samples have retention time shift in the reference peak, which is not normal! we should adjust the retention time once before the batch.)
2) When we run the same sample from the same vial, the Internal standard response varies although it should be the same!
3) Abnormal hump in the baseline in the TIC, which is very obvious especially in the ions 191 & 369. See attached ppt (Slide 1 & 2).
4) Sometimes when we run the same sample from the same vial (in between a batch of 10 samples, all were good except one in the middle) under the same conditions & protocol twice, some peaks in the same ion could change completely from almost baseline to very high abundant peaks which is not normal as well and this was because something went wrong in the injection, see the scale, although it is an automated injector. So sometimes the machine can be wrong. See the attached ppt (Slide 3-8).
We do our best for machine maintenance, which run periodically, and go with all manual trouble shooting but the problems still there. Your cooperation in his is highly appreciated.
1) Retention time shift between the samples in the same batch. (As usual we run the standard after checking the tune & the blank, then we adjust the retention time of the reference peak in the standard, then we run a batch of 10 samples, we found all the samples have retention time shift in the reference peak, which is not normal! we should adjust the retention time once before the batch.)
2) When we run the same sample from the same vial, the Internal standard response varies although it should be the same!
3) Abnormal hump in the baseline in the TIC, which is very obvious especially in the ions 191 & 369. See attached ppt (Slide 1 & 2).
4) Sometimes when we run the same sample from the same vial (in between a batch of 10 samples, all were good except one in the middle) under the same conditions & protocol twice, some peaks in the same ion could change completely from almost baseline to very high abundant peaks which is not normal as well and this was because something went wrong in the injection, see the scale, although it is an automated injector. So sometimes the machine can be wrong. See the attached ppt (Slide 3-8).
We do our best for machine maintenance, which run periodically, and go with all manual trouble shooting but the problems still there. Your cooperation in his is highly appreciated.