Hello,

I am a student, learning and working on a Varian GC. I was given the task to calibrate our new GC in the lab. Can anyone please advice on the suitable internal standard that I should use if I am interested in C12-C18 fatty alcohol?

Thanks in advance.

An internal standard should be a substance wich is chemically alike to the anlytes you want to quantify. So using an alcohol (C8 or C10) would be a good starting point

Gilbert Staepels

Actually, I would use tridecanol or pentadecanol, obtainable from aldrich in quite pure form. I usually make trimethylsilyl derivatives of the fatty alcohols to improve peak shape also.

getting started using gc/ms to quantitate steroid hormones in plasma; looking for class offering wet lab for hands-on training w/internal std calibration using deuterated std's (isotope dilution mass spectrometry. if anyone knows where such training is available, please let me know. thanx.

For an analysis that is more sensitive to branched chains I would use an acetate derivative instead of the TMS ether. Both may be adequate but if branched chains are to be separated then I would make acetates. In the 1980s when I changed this analysis my std went from 99% to 94% in purity. If you want the same carbon number alcohols to elute together, then use the TMS ether.

Rodney George