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Abstract: A liquid chromatographic (LC)–tandem mass spectrometry (MS/MS) method was developed for simultaneous determination of stilbenes, diethylstilbestrol (DES), hexestrol (HEX), and dienoestrol (DEN) in animal tissue. Sample clean-up and analyte enrichment was performed by automated solid-phase extraction (ASPE) with a silica gel cartridge. Detection capabilities (CCβ) related to the transition products of lowest abundance for the method were 0.04–0.45ngg−1 in tissue and were achieved using atmospheric pressure chemical ionization (APCI) in negative mode. The use of an internal standard in combination with the simplified sample preparation led to a sensitive and reliable analytical method. The recovery level of the method was 84–108% for DES and DEN between 0.5 and 5ngg−1, and 59–87% for HEX between 0.25 and 2.5ngg−1. [Copyright &y& Elsevier]

Abstract: Epitestosterone (ET) has been used as a masking agent and prohibited by the World Anti-Doping Agency (WADA) because its administration will decrease the urinary T/ET ratio, a marker of testosterone (T) administration. In this study, an off-line immunoaffinity extraction coupled with high performance liquid chromatography (HPLC) was developed to quantify the endogenous steroid ET in human urine. The immunoaffinity column (IAC) was prepared by immobilizing the anti-ET monoclonal antibodies on CNBr-activated Sepharose 4B, which can remove the contaminations and non-target compounds from matrix to enrich the target analyte ET. The mobile phase was ammonium acetate (10mM, pH 4.0)/acetonitrile (45/55, v/v) at an isocratic flow of 1.0mL/min and the UV absorbance detection wavelength was 244nm for the detection of ET. The IAC showed good reliability and durability since it had been used for more than 100 runs in a year. The limit of quantification (LOQ) was 1ng/mL. Satisfied repeatability and precision of the day-to-day and within-day were obtained with the RSD values less than 10%. Results of the recovery of the urine samples were ranged from 98% to 102% with repeatability less than 9%, indicating that the method developed can be used for the real urine sample analysis. [Copyright &y& Elsevier]