Topics in GC & HPLC

Instead of trying to bribe shy readers with autographed photos like some of my other colleagues, I'm going to ask for help on an issue that's been bugging me for the past couple of days. Anybody who has any feedback will get 10 wizard dollars. That's enough for a t-shirt. Those of you who aren't interested in Restek apparel should still read on, because this is an interesting phenomenon, and I'd like some help explaining it. While performing a splitless injection of amphetamines in methanol, I see a large peak that doesn't show up in split injections. It looks like a separate compound forming from my primary amine in the injection port, as there is a common mass difference of 12m/z for elements of the two spectra. This peak disappears when the sample solvent is changed to ethanol. For a full explanation, check out the figure. I wouldn't recommend methanol for amphetamines analysis anyway, so it's kind of a moot point, but it would be nice to have an explanation for what's happening.