Determination of disulfoton in surface water samples by cloud-point extraction and gas chromatography

摘要

This article proposes an alternative method, using cloud-point extraction and gas chromatography, for extraction and determination of disulfoton in water samples. For cloud-point extraction, the nonionic surfactant Triton X-114 was used. Before gas chromatography, a cleanup stage for surfactant removal from the extracts was optimized. Cleanup used two columns, in series, containing silica gel and Florisil, with methanol:hexane (1:1) as eluent, resulting in the removal of more than 95% of the Triton X-114. Factors such as ionic strength ( >0.5 mol L~(-1)) and surfactant concentration (1.0% w/v) increased the extraction efficiency of the cloud-point methodology, yielding disulfoton recoveries of almost 100%. Compared with liquid-liquid extraction, the cloud-point methodology was more efficient, with a better detectability, and resulted in a significant reduction in solvent volume.