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

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 μg kg−1. 5,6-Dimethyl-2-thiouracil is used as internal standard. CCα and CCβ are in the ranges 4.3–16.1 μg kg−1 and 8.7–20.7 μg 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 Agència de Salut Pública de Barcelona and allows processing of up to 20 samples per day.