Detection of clenbuterol residues in hair

Sixty rats were grown in the presence of 10 (n = 30) and 100 (n = 30) micrograms kg-1 body mass of clenbuterol for a period of 10 d. An immunoextraction step coupled with a competitive enzyme immunoassay allowed the quantification of clenbuterol in hair upon 20 (10 micrograms kg-1) and 30 d (10 micrograms kg-1) after the last dose. This accumulation in hair contrasts with the rapid clearance in tissues. The nature of the immunoreactive material was confirmed by mass spectrometry.