Detection of exogenous intake of natural corticosteroids by gas chromatography/combustion/isotope ratio mass spectrometry: application to misuse in sport.

A detailed procedure for the analysis of exogenous hydrocortisone and cortisone in urine by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is proposed. As urinary levels of hydrocortisone are rather low for GC/C/IRMS analysis, the focus is on the main corticosteroid metabolites, tetrahydrocortisone (THE) and tetrahydrocortisol (THF). Following different solid phase extraction purifications, THE and THF are oxidized to 5β-androstanetrione before analysis by GC/C/IRMS. Significant differences in δ13C‰ values of synthetic natural corticosteroids and endogenous human corticosteroids have been observed. Therefore, a positive criterion, to detect exogenous administration of synthetic corticosteroids in anti-doping control, is proposed. Copyright © 2000 John Wiley & Sons, Ltd.