Analytical methodology for the detection of beta(2)-agonists in urine by gas chromatography-mass spectrometry for application in doping control

A comprehensive gas chromatographic-mass spectrometric (GC-MS) procedure fo r detection in urine of beta(2)-agonists having different alkyl or phenylal kyl chains at the nitrogen atom is described. The method is based on an enz ymatic hydrolysis with P-glucuronidase from Helix pomatia, followed by a so lid-phase extraction procedure using Bond Elut Certify columns. The influen ce of urine pH in the extraction recovery has been studied and pH 9.5 was f ound to give best recovery and cleaner extracts. After pH adjustment, the s ample was applied to the pre-conditioned cartridges and after a washing ste p, the Pz-agonists were eluted with a mixture of chloroform and isopropanol (80:20, v/v) containing 2% ammonia. The residues were derivatised with N-m ethyl-N-trimethylsilyl-trifluoroacetamide (MSTFA), and analysed by GC-MS. A validation procedure for qualitative analysis of Pz-agonists in urine was performed. Selectivity of the method showed that no interfering peaks were observed for most of the compounds at the retention time of the Pz-agonists . Extraction recoveries ranged from 68.1 to 103.7% in urine samples. Detect ion limits from 0.5 to 5 ng ml(-1) were obtained using selected-ion monitor ing. Intra-assay precision ranged between 2.3 and 13.8% for ail compounds e xcept for fenoterol. The International Olympic Committee (IOC) criteria for compound identification were fulfilled for the compounds studied. The opti mised method was successfully applied to analyse urine samples obtained fro m excretion studies in healthy volunteers. (C) 2000 Elsevier Science B.V. A ll rights reserved.