GC MS - contaminant 190.9 - 206 - 208

[KevinBe]

Dear All,

I just cleaned the source, changed the column of my GC MS but I see a strange contamination (see attached file)



Any idea about what this could be?

Thanks a lot,

Kevin

[JMB]

m/z 191 & 207 are both indicative of siloxane column bleed and tend to increase as the temperature increases; suggest that you disconnect the column from the MS and run a conditioning temperature program.