title: Quantification of clenbuterol at trace level in human urine by ultra-high pressure liquid chromatography-tandem mass spectrometry.
abstract: Clenbuterol is a β2 agonist agent with anabolic properties given by the increase in the muscular mass in parallel to the decrease of the body fat. For this reason, the use of clenbuterol is forbidden by the World Anti-Doping Agency (WADA) in the practice of sport. This compound is of particular interest for anti-doping authorities and WADA-accredited laboratories due to the recent reporting of risk of unintentional doping following the eating of meat contaminated with traces of clenbuterol in some countries. In this work, the development and the validation of an ultra-high pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the quantification of clenbuterol in human urine is described. The analyte was extracted from urine samples by liquid-liquid extraction (LLE) in basic conditions using tert butyl-methyl ether (TBME) and analyzed by UHPLC-MS/MS with a linear gradient of acetonitrile in 9min only. The simple and rapid method presented here was validated in compliance with authority guidelines and showed a limit of quantification at 5pg/mL and a linearity range from 5pg/mL to 300pg/mL. Good trueness (85.8-105%), repeatability (5.7-10.6% RSD) and intermediate precision (5.9-14.9% RSD) results were obtained. The method was then applied to real samples from eighteen volunteers collecting urines after single oral doses administration (1, 5 and 10μg) of clenbuterol-enriched yogurts.
authors.affiliation: Swiss Laboratory for Doping Analyses, University Center of Legal Medicine, West Switzerland, Chemin des Croisettes 22, 1066 Epalinges, Switzerland.
authors.forename: Raul
authors.initials: R
authors.lastname: Nicoli
authors.forename: Michael
authors.initials: M
authors.lastname: Petrou
authors.forename: Flavia
authors.initials: F
authors.lastname: Badoud
authors.forename: Jiri
authors.initials: J
authors.lastname: Dvorak
authors.forename: Martial
authors.initials: M
authors.lastname: Saugy
authors.forename: Norbert
authors.initials: N
authors.lastname: Baume
mesh_terms: D000318:Adrenergic beta-Agonists / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002976:Clenbuterol / Q000652:urine*; D004300:Doping in Sports; D005506:Food Contamination / Q000032:analysis; D006801:Humans; D059625:Liquid-Liquid Extraction / Q000379:methods; D008297:Male; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000318:Adrenergic beta-Agonists; D002976:Clenbuterol