An Improved LC-MS-MS Method for the Determination of Clenbuterol in Human Urine

An improved liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the screening and confirmation of clenbuterol in human urine was developed and validated in this transitions (277.1 -> 132.0 and 277.1 -> 259.1), two new ion transitions (277.1 -> 132.0 and 277.1 -> 168.0) were utilized for this new screening procedure. Compared with existing methods of clenbuterol screening in human urine, the developed method is of higher sensitivity and reduces the number of false-positive results. The limit of detection (LOD) of the method proposed is 2 pg/mL, which is lower than the minimum required performance limit (MRPL) set by World Anti-Doping Agency (WADA). The success and reliability of the method in doping control analysis was demonstrated for the analysis of a 2011 EQAS (External Quality Assessment Systems) -01 human urine sample obtained from WADA.