Carbon isotopes ratio of endogenous urinary steroids of the Cuban population of athletes studied for doping purposes

The aim of this work was to validate the GC/C/IRMS method in Havana Antidoping Laboratory and verify its implementation with a study of the Cuban population. The method showed to be precise and accurate inside the linear working range, the limit of quantification and the uncertainty are compliant with TD2019IRMS. The study of the Cuban population showed no differences between female and males for δ13 C values. Only three values of Δδ13 C did show significant differences between sexes (PD-T, OHA-T and 11-keto-Et-T). Values of δ13 C between -17.8 and -21.2 ‰ (upper and lower limits based on normal distribution) are in agreement with other populations where C4 plants derivatives prevail in the diet.