Determination of organochlorine pesticides in snow water samples by low density solvent based dispersive liquid-liquid microextraction.

A simple, rapid, efficient, and environmentally friendly pretreatment based on a low-density solvent based dispersive liquid-liquid microextraction was developed for determining trace levels of 17 organochlorine pesticides in snow. The parameters affecting the extraction efficiency, such as the type and volume of the extraction and dispersive solvents, extraction time, and salt content, were optimized. The optimized conditions yielded a good performance, with enrichment factors ranging from 271 to 474 and recoveries ranging from 71.4 to 114.5% and relative standard deviations between 1.6 and 14.8%. The detection limits, calculated as three times the signal-to-noise ratio, ranged from 0.02 to 0.11 μg/L. The validated method was used to successfully analyze 17 analytes in snow water samples, overcoming the drawbacks of some existing low-density solvent liquid microextraction methods, which require special devices, large volumes of organic solvents, or complicated operation procedures.