Suitability of N,O-bis(trimethylsilyl)trifluoroacetamide and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide as derivatization reagents for the determination of the estrogens estrone and 17alpha-ethinylestradiol by gas chromatography-mass spectrometry

This paper describes apreviously unreported problem with the use of N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) and N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) to derivatise the natural hormone estrone (E1) and the synthetic estrogen 17alpha-ethinylestradiol (EE2). The resulting trimethylsilyl (TMS) and t-butyldimethylsilyl (TBS) derivatives of EE2 were partially converted to their respective El derivatives. Therefore, these reagents may not be suitable for simultaneous determination of estrogens in environmental samples, which raises questions about the reliability of results from some earlier studies.