Enantiomeric analysis of clenbuterol in Chinese people by LC-MS/MS to distinguish doping abuse from meat contamination.

Follow-up investigations are often required for clenbuterol-positive cases. A method to distinguish doping abuse from meat contamination was developed. A total of 26 volunteers were recruited to ingest clenbuterol contaminated-pork and clenbuterol tablets. For 20 volunteers, after ingestion of contaminated-pork, R-(-)/S-(+)-clenbuterol ratio was <1.0, while the value was >1.0 after taking clenbuterol tablets. However, after taking clenbuterol tablets, some ratio points of the other six volunteers were between 0.9 and 1.0. A case of an abnormal cold and fever, which returned to normal after recovery, was also reported firstly. A change in R-(-)/S-(+)-clenbuterol was reported in the Chinese population initially. A ratio of 0.9 was recommended in doping related cases for the Chinese population.