Comparison of sensitivity between gas chromatography-low-resolution mass spectrometry and gas chromatography-high-resolution mass spectrometry for determining metandienone metabolites in urine

In doping control laboratories the misuse of anabolic androgenic steroids i s commonly investigated in urine by gas chromatography-low-resolution mass spectrometry with selected ion monitoring (GC-LRMS-SIM). By using high-reso lution mass spectrometry (HRMS) detection sensitivity is improved due to re duction of biological background. In our study HRMS and LRMS methods were c ompared to each other. Two different sets were measured both with HRMS and LRMS. In the first set metandienone (I) metabolites 17 alpha-methyl-5 beta- androstan-3 alpha,17 beta-diol (II), 17-epimetandienone (III), 17 beta-meth yl-5 beta-androst-1-ene-3 alpha,17 alpha-diol (IV) and 6 beta-hydroxymetand ienone (V) were spiked in urine extract prepared by solid-phase extraction, hydrolysis with beta-glucuronidase from Escherichia coli and liquid-liquid extraction. In the second set the metabolites were first spiked in blank u rine samples of four male persons before pretreatment. Concentration range of the spiked metabolites was 0.1-10 ng/ml in both sets. With HRMS (resolut ion of 5000) detection limits were 2-10 times lower than with LRMS. However , also with the HRMS method the biological background hampered detection an d compounds from matrix were coeluted with some metabolites. For this reaso n the S/N values of the metabolites spiked had to be first compared to S/N values of coeluted matrix compounds to get any idea of detection limits. At trace concentrations selective isolation procedures should be implemented in order to confirm a positive result. The results suggest that metandienon e misuse can be detected by HRMS for a prolonged period after stopping the intake of metandienone. (C) 1999 Elsevier Science B.V. All rights reserved.