Determination of ethylene thiourea in urine by HPLC-DAD

Ethylene thiourea (ETU) is a metabolite of ethylenebisdithiocarbamates (EBDCs); it is the best indicator of exposure to these fungicides. Therefore, high-performance liquid chromatography with photodiode-array detection (HPLC-DAD) was optimized and validated for the determination of ETU in human urines. Urine samples were extracted by solid-phase extraction using Extrelut and analyzed using HPLC-DAD set at 231 nm. The analyses were carried out using a mobile phase of 0.01 M phosphate buffer (pH 4.5) on a C18 Uptisphere NEC-5-20, 250- x 4.6-mm x 5-microm column. The internal standard used was 4-pyridinecarboxylic acid hydrazide. The method was successfully validated in compliance with requirements set by the International Committee on Harmonization 1996. The lower limit of quantitation was at 1 microg/L, and the linearity was studied from 1 to 100 microg/L. There were 272 urine samples collected from farmers exposed to EBDCs in different regions in France analyzed in this study.