Hair analysis, a reliable and non-invasive method to evaluate the contamination by clenbuterol

• A highly effective and accurate LC/MS/MS method was developed to determine clenbuterol in hair.
• Hogs fed with clenbuterol were found to have a high and long residue in hair.
• Hogs from market were all contaminated and their black hair had a higher residue than white ones.
• One hundred and thirty-six volunteers accepted the test and 60 percent of them were found to have clenbuterol residue in their hair.

The illegal use of clenbuterol has been an increasingly serious issue in today's livestock products industry. It becomes an important project to develop a reliable approach to detect its content in food animals. A simple and sensitive LC–MS/MS method was developed to detect clenbuterol residue in hair, with the low limit of quantitation (LLOQ) about 0.5 ng/g. Hogs fed with 340 µg/day of clenbuterol for 2 weeks were found a high clenbuterol residue in their hair approximately at 1–2 months after withdrawal. There remained 3.31 ng/g clenbuterol in hog hair approximately 5 months after the last administration, focused on the tip of the hair (mainly in hogs with dark hair). An extensive contamination was observed in twenty investigated market hogs whose dark hair obviously had a higher clenbuterol residue than the light ones (p=0.017, t test). Volunteers (60.3 percent) from Xuhui district (Shanghai) were found to have a detectable amount of clenbuterol in their hair (>0.5 ng/g). In conclusion, hair residue detection is a reliable method to evaluate the clenbuterol contamination in animals and humans. Meat supply in the Xuhui district might have serious potential safety risks which should be further investigated and discussed to determine the safety range of clenbuterol residue.