Screening and confirmation of thyreostatics in urine by gas chromatography with nitrogen-phosphorus detection and gas chromatography-mass spectrometry after sample clean-up with a mercurated affinity column.
R Schilt, J M Weseman, H Hooijerink, H J Korbee, W A Traag, M J van Steenbergen, W Haasnoot
Methods are described for the screening and confirmation of residues of the thyreostatics thiouracil, methylthiouracil and propylthiouracil in urine samples of cattle at levels down to 25 micrograms/l. After a selective preconcentration of the thiol-containing thyreostatics on a mercurated affinity column, the analytes are derivatized by extractive alkylation and analysed by gas chromatography with nitrogen-phosphorus or mass spectrometric detection.