Determination of 25 disinfection by-products in drinking water using liquid-liquid extraction and gas chromatography

Abstract

To establish a liquid-liquid extraction and gas chromatography method for the determination of 7 kinds of haloacetaldehydes, 7 kinds of haloacetonitriles, 7 kinds of halonitromethanes and 4 kinds of haloacetamides in drinking water. A liquid-liquid extraction gas chromatography technique was employed. Experimental parameters, such as capillary column type, inlet temperature, concentration of salting out reagent and sample pH were optimized to develop an analytical method, and then method validation was conducted. HP-5 MS UI column(30 m×0.25 mm, 0.25 μm), inlet temperature at 180 ℃, addition of 8 g sodium chloride in 50 mL water sample and pH 4-5 were chosen as the final parameters. Good correlation coefficients were obtained in the linear range of 0.20-15 μg/L, with r greater than 0.999.Methods detection limits were between 0.008-0.088 μg/L. When spiked concentration was 1.0 μg/L for pure water and tap water, the recoveries were 81%-106% and 75%-117%, respectively, and relative standard deviations were both less than 4%. When spiked concentration was 12 μg/L for pure water and tap water, the recoveries were 92%-101% and 86%-106%, respectively, and relative standard deviations were less than 4% and 2%, respectively. This method is simple, sensitive, and effective. It is suitable for simultaneous determination of 25 disinfection byproducts in drinking water.