by
KipDM » Thu Sep 24, 2015 6:31 pm
depending on which column type you are using you may want to try the following:
inject 2-3 shots (as if they were a sample) of pure methanol, make sure exact same heat ramp and to keep constant temperature on MS then
inject 2-3 shots of pure hexane
i have experience using 5% phenyl 95% dimethylpolysiloxane so i don't know if that is acceptable on other columns.
this is really just to try and make sure there has been no atmospheric water absorption that has not bee driven off.
i know that sounds basic too, but if you took the MS down for any period of time it could actually be there not noticeable without thew flo from the GC.
the water staying constant while you N2 varies is what makes me assume think this may help.
