Artifact formation due to ethyl thio-incorporation into silylated steroid structures as determined in doping analysis

Structure and mechanism of formation of an important ion in doping control

“…The NH 4 I and ethanethiol ensure near-complete keto-enol trimethylsilylation (at the low risk of ethyl thio-incorporation into silylated steroid structures) [7,8], and therefore eliminates the need for methyl oxime derivatives. Following derivatization samples were injected directly into the GC-MS.…”

“…Breakdown curve generated by CID and analysis by a second stage of mass spectrometry for the major product ions of the m/z 143 precursor ion derived from TMS-derivatized epimetendiol(7). data at increasing collision energies were collected to construct breakdown curves[12] of the major product ions of D-and Aring derived ions with m/z 143 and of D-and A-ring derived ions with m/z 157.…”

Pitfalls in trimethylsilylation of anabolic steroids

“…Although the results described in this paper are inadequate to obtain fully detailed mechanistic overview on such attacks in steroid analysis, they illustrate the still insufficient knowledge of the silylation mechanism. Moreover, these artefacts lead to confusion in the identification and quantification processes [28,31]. A new derivatisation reagent mixture consisting in BSA then completed with (MSTFA/I 2 ) (100:1 (v/w)) in proportion to (20:0.5 (v/v)) and finally heated for 30 min at 60 • C was developed for the simultaneous trimethylsilylation of a wide range of natural steroids with various chemical functions at ng kg −1 levels in kidney fat.…”

“…Such phenomenon are also noted in cases of derivatisation of standards with reaction mixtures comparing to pure reagent The phenomenon is more obvious in crude sample comparing to pure standard. Co-extracted components probably play a crucial and unexpected role in the reaction [28][29][30][31]. Thus, the attack of a trimethylsilyl radical on the double bond of enol-trimethylsilyl ether for ␣,␤-ketones such as testosterone [32] that subsequently eliminates a trimethylsilyl group was observed (Fig.…”

Novel analytical methods for the determination of steroid hormones in edible matrices

“…This was also used by Hartmann and Steinhart [48] and Fuh et al [56], however, NH 4 I was replaced by trimethylsilytrifluoroacetamide (TMIS), which reacts as catalyst. Besides that, the formation of additional unexpected derivatives or by-products (artifacts) following derivatization of steroid hormones was discussed [94][95][96].…”