DETERMINATION OF MESOCARB METABOLITES BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH UV DETECTION AND WITH MASS-SPECTROMETRY USING A PARTICLE-BEAM INTERFACE

A method of screening for mesocarb ingestion in doping control is desc ribed. After alkaline extraction with ethyl acetate, samples are analy sed by reversed-phase high-performance liquid chromatography (HPLC) wi th UV detection. A peak with a shorter retention time than and a UV sp ectrum identical with those of unchanged mesocarb was obtained when po sitive urine extracts were analysed. The metabolite was identified as the sulphate conjugate of p-hydroxymesocarb after HPLC-mass spectromet ry with a particle-beam interface and hydrolysis studies. The compound was detected in urine until 48-72 h after administration of single do ses of 10 mg. Unchanged mesocarb and free p-hydroxymesocarb were not d etected in the samples studied.