Determination of thiodiglycolic acid in urine by ion chromatography with solidphase extraction

Objective To establish a SPE-IC method to determine the thiodiglycolic acid in the urine of workers who were exposed to vinyl chloride monomer. Methods The samples were prepared by the process of being centrifuged and purified by C18 SPE column before separated by AS19 anion exchange column and detected by conductivity detector. The thiodiglycolic acid were characterized by the retention time and quantified by peak area and external standard method. Results The range of linearity was 0.05~50.00 μg/ml, and the correlation coefficient was 0.999 9. The method detection limit was 0.1 μg/ml and the method quantitative limit was 0.3 μg/ml. The within-run precision was 1.26%~5.03% and the betweenrun precision was 0.50%~8.78%. The spiked recoveries were 80.10%~104.20%. Samples could bestored at-20 ℃ for at least 2 weeks. The determination of thiodiglycolic acid could not be interfered by chloroacetic acid, dichloroacetic acid, trichloroacetic acid and other endogenous ionic compounds. Conclusion This method is feasible for determination of thiodiglycolic acid in the urine of workers who were exposed to vinyl chloride monomer. Key words: Thiodiglycolic acid; Urine; Solid-phase extraction; Chromatography