Chromatography Forum

would infusing a pyridine & BSTFA/TMCS mixture into an ion trap LCMS (Thermo LCQ) cause problems? .... in a moment of twisted logic I derivatized & infused a compound and realized the product is probably far too large for regulat GCMS so I thought "what about APCI on our ion trap??" well we got some awesome results from the TMS'd compound but then after an hour or so of infusing everything suddenly changed and none of the ions are the same or make any sense, I've gone back to my usual ESI with my usual stds and nothing makes sense there either... I'm getting a good signal, just don't know what I'm looking at any more! all the mass spec diagnostics check out. I remember reading about TEA causing problems in an ion trap, would pyridine do the same?
help!

confused & worried, MA

I've had a similar experience with the LCQ, after injecting a certain compound several times the mass spectrum didn't make sense.

The problem was that after a few injections (with the LCQ injection option, not the HPLC's autosampler) the system got contaminated. All it needed was a thorough clean up.

Thanks for the advice Teodor,
it seems the problem mysteriously solved itself... I infused the calibration mix in ESI and all the masses were off by 12 or 14, bizarre, but then I had it jut check the calibration (all except the mass calibration, 'cos I could see that was off) and suddenly things went back to normal, good old ultramark was back in the 22's and everything looked normal again... so I don't know if the problem had anything to do with the pyridine / TMS stuff or if my LCQ had a momentary lapse of reason... I hate it when you don't know what went wrong and what made it right again!!