title: Gas chromatography-tandem mass spectrometry determination of 17alpha-ethinylestradiol residue in the hair of cattle. Application to treated animals.
abstract: A gas chromatography-tandem mass spectrometry (GC-MS(2)) method for the detection and quantification of 17alpha-ethinylestradiol in the hair of cattle has been developed, and uses an ion trap analyzer. After the digestion of 500 mg of hair by alkaline digestion using 1 M NaOH, extraction and purification of the steroid were performed in the same step by means of diphasic dialysis. This technique is a semipermeable-membrane technology developed for the direct extraction of relatively low-molecular-mass analytes. The process was performed by employing acetate buffer to homogenize the digested hair, dichloromethane as the extraction solvent at 37 degrees C, and stirring at 150 rpm for 4 h. The recovery was between 74 and 94%. The detection limit was 0.52 ng/g in hair. To evaluate the validity of the methodology, five animals, approximately 3 months old, received an intramuscular anabolic dose of the drug. The xenobiotic could be detected 7 or 14 days after the treatment (between 2.01 and 23.61 ng/g), and until the end of the study (day 98). No statistical difference between hair color and hair assay outcomes was found.
authors.affiliation: Laboratorio de Higiene e Inspección de Alimentos, Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Veterinaria, Universidad de Santiago de Compostela, Campus de Lugo 27002, Spain.
authors.forename: A A
authors.initials: AA
authors.lastname: Durant
authors.forename: C A
authors.initials: CA
authors.lastname: Fente
authors.forename: C M
authors.initials: CM
authors.lastname: Franco
authors.forename: B I
authors.initials: BI
authors.lastname: Vázquez
authors.forename: A
authors.initials: A
authors.lastname: Cepeda
mesh_terms: D000818:Animals; D002417:Cattle; D004350:Drug Residues / Q000032:analysis; D045166:Estradiol Congeners / Q000032:analysis*; D004997:Ethinyl Estradiol / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006197:Hair / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D045166:Estradiol Congeners; D004997:Ethinyl Estradiol