[Determination of dimethyl sulphate in environmental samples with GC-ECD].

OBJECTIVE:To develop an gas chromatography-electrophoretic capture detection (GC-ECD)method for determining dimethyl sulphate (DMS) in environmental samples. METHODS:The environmental samples were dissolved with acetone and the DMS was reacted with KI. The reaction product of methyl iodide was extracted with Hexane and determined by GC-ECD, with HP-5 (30.0 m x 0.32 mm x 0.25 microm) as column, high purity nitrogen as carries, 60 degrees C for column temperature and 240 degrees C for ECD and injector temperature, and 5:1 for split ratio. RESULTS:The linear range appeared from 0.05 microg/mL to 2.0 microg/mL. The detection limit was 0.0011 microg/mL. The precision [measured by relative standard deviation (RSD)] of peak area and reserved time for the standard solution was 4.95% and 0.15% respectively for intra-day detections, and 5.99% and 0.83% respectively for inter-day detections. Satisfactory results were obtained for the analysis of environmental samples. The RSD for the water and soil samples were 9.6% and 7.5% respectively and the recoveries were 76.0%-85.0% and 82.0%-110.0% respectively. CONCLUSION:The method was simple, accurate, sensitive and applicable for DMS analysis in environmental samples.