title: External contamination of bovine hair with beta2-agonist compounds: evaluation of decontamination strategies.
abstract: Hair analysis has shown great potential in the control of illegal use of veterinary drugs such as beta2-agonists. However, it has been shown that hair can be externally contaminated with drugs which can lead to false positive results. Exposure of bovine hair to aqueous solutions of beta2-agonist compounds results in incorporation of these drugs into the hair. Standard hair washing procedures found in the literature: detergent (Tween-20), phosphate buffer or organic solvents (dichloromethane or methanol) cannot eliminate this external contamination. Beta2-agonists can be extracted from hair very efficiently with 0.1 M HCl, the extraction kinetics of externally and endogenously accumulated clenbuterol at room temperature are different which makes it feasible to discriminate between them. Treatment of hair samples with a 0.1 M HCI solution for 2 h at room temperature results in a ratio of clenbuterol content in the wash solution to clenbuterol content in the washed hair equal to or less than 0.25 for samples from treated cattle; whereas this ratio is equal to or higher than 0.70 for externally contaminated samples. The design of the study was intended to resemble the plausible scenario of hair being sampled a short time after external contamination. A similar study to detect external contamination for hair sampled a long time after exposure is in progress.
authors.affiliation: Laboratorio Reg Salud Pública, Dir Gral Salud Pública, Comunidad de Madrid, Spain. mhernandez@trasto.cbm.uam.es
authors.forename: M
authors.initials: M
authors.lastname: Hernández-Carrasquilla
mesh_terms: D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists / Q000032:analysis*; D000818:Animals; D002417:Cattle; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006197:Hair / Q000737:chemistry*
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D000318:Adrenergic beta-Agonists