Use of new silylating agents for identification of hydroxylated steroids by gas chromatography-electron impact-mass spectrometry.

Abstract

A difference of methylene unit value, .DELTA.[MU], was used for the determination of the hydroxyl group number of steroids by means of gas chromatography. This index is defined by the difference in the methylene unit value between trimethylsilyl and other dimethylalkylsilyl (DMAS) ether derivatives, namely dimethylethylsilyl and dimethyl-n-propylsilyl ethers, of hydroxy steroids. Mass spectra of these derivatives were characterized by the molecular ion cluster, M,M-15 and M-29 (or M-43), where the fragment ion of M-29 (or M-43) appeared in the most case as a base peak. The molecular ion cluster of these derivatives is of great use for estimating the molecular weight. These DMAS ethers provide a valuable information for structural elucidation of hydroxy steroids by gas chromatography-electron impact-mass spectrometry.