-
- Posts: 42
- Joined: Thu Jan 22, 2009 1:43 pm
We are doing GC-MS analysis of manually SPME-extracted volatiles from fermented milk. There are three issues with this:
1. The peaks of our interest as analyzed by MS have weird shapes as indicated by arrows in Fig. A
2. There is a huge peak at the beginning of all the chromatograms including that with blank fiber as indicated in Fig B. The mass spectra in this area match with those of water, nitrogen, etc. This peak appears only with manual SPME and not with autosampler injection of liquid standards.
3. There are many peaks of the matrix (siloxane) in the SPME chromatograms and not standards’ chromatograms (liquid injections), meaning there is bleeding from SPME matrix. We do condition the SPME fiber for 30 min in the injector before headspace extraction. The fiber has been used only for about 10-20 times till now.
Can anyone recommend any remedies to troubleshoot these issues?
Many thanks
https://postimg.cc/vx1YY8N8