Methylation of phase II metabolites of endogenous anabolic androgenic steroids to improve analytical performance

Intact phase II metabolites of endogenous anabolic androgenic steroids give important information about metabolism and have the potential to improve the detection of doping with testosterone. Currently applied methods for liquid chromatography –mass spectrometry analysis include chemical derivatization at the steroid moiety, which can pose challenges regarding chromatographic performance, for example, poor peak shape. Methylation with trimethylsilyl-diazomethane at the acidic moiety of the phase II conjugate improves analytical performa nce by the formation of narrower and more intense peaks. AbstractThe study of intact phase II metabolites of endogenous anabolic androgenic steroids (EAAS) gives important information about metabolism and has the potential to improve the detection of doping with testosterone. For analysis with liquid chromatography –mass spectrometry (LC-MS), chemical derivatization at the steroid moiety is a technique to improve the positive ionization efficiency of glucuronidated/sulfated EAAS under collision-induced dissociation (CID) conditions. However, regarding the chromatographic performance, there are still challeng es to address, for example, poor peak shape, which is mainly caused by nondefined adsorption in the chromatographic system. Here, we show a novel derivatization technique for the analysis of selected phase II metabolites of EAAS, where the acidic moiety of the glucuronide/sulfate is methylated with different methylation reagents to red...
Source: Drug Testing and Analysis - Category: Drugs & Pharmacology Authors: Tags: RESEARCH ARTICLE Source Type: research