Liquid chromatography-electrospray method for the determination of ionisation-mass spectrometry based estradiol benzoate in hair of cattle

A liquid chromatography (LC)-based method with mass spectrometric (MS/MS) detection was developed for the determination of estradiol benzoate residues in hair of cattle. First hair samples were pulverized with a ball mill followed by treatment with the reducing agent Tris(2-carboxyethyl)phosphine hydrochloride (TCEP). After liquid/liquid extraction samples were further purified by solid-phase extraction. Finally samples were analyzed with LC-MS/MS using deuterated estradiol benzoate as internal standard. The method was validated following the latest EU guidelines for screening methods using blank hair samples spiked at 5 ng g(-1). The detection capability (CCP) was less than 5 ng g(-1) and the decision limit (CCalpha) was 1.6 ng g(-1). The recovery was 27% at the 5 ng g(-1) level and the accuracy was 95%. Confirmation, with two MS/MS transitions, was possible at a concentration of 5 ng g(-1) or higher. Incurred samples obtained from different animal experiments were analyzed and the presence of estradiol benzoate was confirmed. Finally hair samples from different slaughterhouses were analyzed. (C) 2004 Elsevier B.V. All rights reserved.