An Improved Method for the Capillary Gas Chromatographic Derivatization of Polyhydroxylated Steroids Having tert-Hydroxyl Groups

Abstract

An improved method for a suitable derivatization of polyhydroxylated steroids having one or two tert-hydroxyl groups at the 5beta-, 14alpha-, 17alpha-, 24-, and/or 25-positions by capillary gas chromatography (CGC) is described. By using trimethylsilyl triflate as a silylating reagent and 2,6-lutidine as a catalyst, each of 5beta-cholane and 5alpha-cholestane series of steroids was successfully transformed into trimethylsilyl (TMS) ether derivatives to give a single CGC peak under mild conditions. More bulky triethylsilyl (TES) etherification of 14alpha- and 17alpha-hydroxy compounds provided multiple CGC peaks arising from completely- and/or incompletely-derivatized TES ethers accompanied by their thermal elimination products.

Distinguishing between human and animal sources of fecal pollution in waters: a review

“…The majority of analytical methods for sterols and bile acids use GC or GC-MS which allows the identification of these sterols with low detection limits; however this requires previous derivatisation. The derivatisation forms commonly used for GC or GC-MS have been the trimethylsilyl (TMS) and other alkylsilyl ethers for hydroxyl functions and the o-methyloxime (OM) for ketonic functions (Bakola-Christianopoulou et al, 1996;Batta et al, 1999;Blau and Halket, 1993;Elliott, 1980;Iida et al, 1987Iida et al, , 2001Iida et al, , 2003.…”