Selected metastable peak monitoring: a new specific technique in quantitative gas chromatography mass spectrometry.

Using the combined electrostatic analyser-magnet scan facility of a double focusing mass spectrometer, the daughter ion peak for the fragmentation, [M-57]+ leads to [M-57-76]+, of a 5alpha-dihydrotestosterone tert-butyl-dimethylsilyl ether was monitored during gas chromatography mass spectrometry. The detection limit was approximately 20 pg. The steroid was detected by this method in an extract of human blood plasma.