Implementation of a Gas Chromatography-Triple Quadrupole Mass Spectrometry method to detect xenobiotics compounds in urine samples for doping control.

Abstract

The World Anti-Doping Agency has, among its functions, the accreditation of laboratories for doping control and to maintain this category it is necessary to comply with international standards. One of the requirements is the constant increasing of the assays sensitivity and with it the increasing of the analytical performance of the laboratory. The present work describes the introduction of a new instrumental method using tandem mass spectrometry to detect forbidden substances, mainly steroids. The assay was validated for 23 analytes, out of them 21 were anabolic steroids, one β2 agonist and one antiestrogenic substance. The validation results showed that the proposed method is highly selective and precise with intra-day variations between 1-17 % for the lowest concentrations and between 2,1-13,9 % for the highest one. The limits of detection were settled between 0,1-2,5 ng/mL except for clenbuterol (0,02 ng/mL). The detector showed no carryover after the analysis of concentrated samples, and the recovery and robustness tests were adequate according to the purpose, screening or confirmation process. Finally, the application of the validated assay to the evaluation of samples from a study of urinary excretion of methyltestosterone allowed to expand the detection window of this steroid, in time.