[kimyacı]

Hello Dear Friends
İ have a problem with interpretting of a GC-MS spectrum of a Volatile oil mixture.I am studying on Volatile oils.I distilled volatile oils from a plant by Clevenger Apparatus and i performed its GC-MS analysis.In the MS spectrum of almost each volatile oil constituent,i saw a peak at 207 m/z.This peak is exist in even the MS spectrum of volatile oils with less molecular weight than 207.For example,i see this peak even in the MS spectrum of alpha pinene whose molecular weight is 136.1 despite of its intensity is low.So i am really wondering a lot to what this peak may belong and how can i interpret this peak.
Any help or any idea about this matter will be appreciated kindly so much
Thanks a lot in advance
(and sorry for my broken English)

[Honclbrif]

Shows up in a standard? Sounds like some sort of systematic contamination. Have any messy lab mates?

Do you have another GC you could run this standard on? Might help to pin down where that 207 is coming from (needle, solvent, the apparatus itself...)

[kimyacı]

Thank u a lot Honclbrif.You may be right