High performance liquid chromatographic determination of 2-thiothiazolidine-4-carboxylic acid as a marker of occupational exposure to carbon disulfide

A gradient HPLC method was used to validate the analysis of 2-thiothiazolid ine-4-carboxylic acid (TTCA) in urine. Four ether solvent systems, were com pared for evaluating the peroxide and solvent effects on TTCA extraction ef ficiency from urine. The TTCA peak was well resolved from adjacent peaks. T TCA recoveries from urine extracted with peroxide-free ethers were higher t han those extracted with peroxide-containing ethers. Average recovery of TT CA extracted with peroxide-containing methyl, t-butyl ether (MTBE) was far more than that extracted with peroxide-containing diethyl ether (Et2O). Per oxides were more readily generated in Et2O than in MTBE. MTBE was found to give up to 86% recovery of TTCA. The limit of detection was estimated to be 35 ng/mL. The coefficients of variation of both intra- and inter-day assay s were less than 3.5% indicating that the proposed method is reliable and r eproducible for TTCA analysis in urine.