Development and validation of a GC-C-IRMS method for the confirmation analysis of pseudo-endogenous glucocorticoids in doping control.

Glucocorticoids are included in the S9 section of the World Anti-doping Agency (WADA) prohibited list international standard. Some among them are pseudo-endogenous steroids, like cortisol and cortisone, which present the same chemical structure as endogenously produced steroids. We are proposing an analytical method based on gas chromatography coupled to isotope ratio mass spectrometry (GC-C-IRMS) which allows discrimination between endogenous and synthetic origin of the urinary metabolites of the pseudo-endogenous glucocorticoids.