Analysis of thyreostatic drugs in thyroid samples by Ultra-Performance Liquid Chromatography tandem mass spectrometry detection

A method based on ultra-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry for the determination of six thyreostatic drugs in thyroid tissue has been optimised and validated in accordance with the Decision 2002/657/EC. Samples are extracted with methanol and the extracts cleaned-up on silica cartridges. The recoveries range from 40% for 6-phenyl-2-thiouracil to 79% for 2-thiouracil. Quantification is carried out with blank tissue samples spiked with the analytes in the range 25-500 mu g kg(-1). 5,6-Dimethyl-2-thiouracil is used as internal standard. CC alpha and CC beta are in the ranges 4.3-16.1 mu g kg(-1) and 8.7-20.7 mu g kg(-1), respectively. Accuracy, expressed as percentage of error, is lower than 6% and relative standard deviation in reproducibility conditions falls between 5.6 and 10.3%. Nowadays, the proposed method is routinely implemented in the laboratory of the Agencia de Salut Publica de Barcelona and allows processing of up to 20 samples per day. (C) 2007 Elsevier B.V. All rights reserved.