Capillary gas chromatographic behaviour of tert.-hydroxylated steroids by trialkylsilylation

Determination of underivatised sterols and bile acid trimethyl silyl ether methyl esters by gas chromatography–mass spectrometry–single ion monitoring in faeces

“…The hydroxyl groups of steroids are conventionally transformed into alkyl silyl ether derivatives with the objective of enhancement of peak shape, resolution and sensitivity [30]. The evaluation of the TIC of underivatised sterols of a faeces sample showed a symmetric peak form without tailing, which may occur in the presence of active centres in the molecule like hydroxyl groups.…”

General Methods for the Extraction, Purification, and Measurement of Steroids by Chromatography and Mass Spectrometry

“…Use of BSA or BSTFA alone will only form such derivatives on non-sterically hindered groups, whereas trimethylsilylimidazole (TSIM) will react with sterically hindered groups (such as the 25-hydroxyl in 25-hydroxyvita-min D or the 17a-hydroxyl in the corticosteroids). Other silyl derivatives have also been used for the separation of bile acids (Iida et al, 1992(Iida et al, , 2001Batta et al, 1998). Other ester derivatives such as formates and acetates have also been used.…”

Pneumocystis carinii Sterol 14α‐Demethylase Activity in Saccharomyces cerevisiae erg11 Knockout Mutant: Sterol Biochemistry

“…Sterol assignments were obtained by GLC-MS analysis with electron ionization (EI) with the sample run under the same GLC conditions. Identification was established by comparison of mass spectra of published data, authentic standards analyzed in this study, and characteristic ions and fragments of material in each GLC peak (Batta et al 1992;Harvey and Vouros 1979;Iida et al 2001;Lawson and Setchell 1988;Shan et al 2003).…”