Determination of clenbuterol residues in bovine hair by using diphasic dialysis and gas chromatography mass spectrometry

A method for the determination of clenbuterol (4-amino-3,5-dichloro-alpha[( tert.-butylamino)methyl]-alcohol hydrochloride) in hair of living cows has been developed. Hair samples were digested in an alkaline medium. The dipha sic dialysis technique is a semi-permeable membrane technology developed fo r the direct extraction of relatively low-molecular-mass analytes such as c lenbuterol. In this case, we used sodium citrate buffer to homogenize the d igested hair, dichloromethane was used as the extraction solvent at 37 degr ees C, and stirring was applied at 150 rpm for 4 h. The analysis was carrie d out using gas chromatography-mass spectrometry. The calibration curve for clenbuterol in hair was linear in the range from 12.5 to 400 ng g(-1). The detection limit of clenbuterol was 5 ng g(-1) and the quantification Limit was 12.5 ng g(-1), in hair. A good inter-day reproducibility was obtained (R.S.D.=7.08%). The repeatability and intra-day reproducibility (50 ng g(-1 ) of hair, n=10) show R.S.D.s of 7.1 and 9.5%, respectively. (C) 1999 Elsev ier Science B.V. All rights reserved.