Isolation and simultaneous LC analysis of thiram and its less toxic transformation product in DS formulation

A simple and sensitive high pressure liquid chromatographic method has been developed for the simultaneous determination of Thiram and its transformation product using isocratic mixture of methanol-water (65:35) at flow rates of 0.75 mL min(-1), PDA detector using UV absorbance (lambda(max)) at 217 nm for Thiram and 265.5 nm for the transformation product. The transformation product was isolated from the commercial DS formulation and has been tentatively assigned the structure by (1)H NMR and ESI-MS spectral data. The separation is dependent on the nature of the mobile phase, its flow rate and the nature of the HPLC column. The detection limit (signal/noise; S/N = 3) for both Thiram and its transformation product was 0.2 ppm. The method has been successfully applied to analysis of soil and soybean samples spiked with Thiram, its transformation product and a commercial sample containing these products.