RESUMEN
A confirmatory method for the analysis of ethinylestradiol extracted from cattle hair was developed. After the extraction of the xenobiotic from the hair, by using alkaline digestion, the purification of the extract was carried out by employing diphasic dialysis. For the optimization of the technique several parameters was evaluated such as pH, extraction solvents, temperatures, times and agitation speeds. The detection and confirmation of the steroid was accomplished by using a GC-MS2 ion trap system after trimethylsilylation. The calibration curve was linear over the range of 4-20 ng/g. The detection and quantification limit were 0.52 and 0.80 ng/g respectively; with recoveries up to 94%.
Asunto(s)
Diálisis/métodos , Residuos de Medicamentos/aislamiento & purificación , Etinilestradiol/aislamiento & purificación , Cromatografía de Gases y Espectrometría de Masas/métodos , Cabello/química , Animales , Calibración , Bovinos , Residuos de Medicamentos/análisis , Etinilestradiol/análisis , Sensibilidad y EspecificidadRESUMEN
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.