Investigation of Some Steroids By Means of Thermospray and Tandem Mass-spectrometry

The detection limits of a number of steroids have been determined by means of loop-injection thermospray (TS) mass spectrometry. The measured limits were found to be in the range 1 pg-10 ng/muL. Combined positive-ion TS/tandem mass spectrometry yielded clear qualitative differences between mass selected protonated testosterone and estriol ions, both of which have the same nominal molecular weight. These differences are necessary for the correct identification of either species which may be present within a complex mixture. The heights of the peaks due to the two competing reaction channels, [M + H]+ and [M + NH4]+. were monitored as a function of the repeller voltage in the range 100-350 V, and the implications of the acquired data are discussed.