Determination of 24 Pesticides in Fish Pond Water by GC-MS Combined with Dispersive Liquid-Liquid Microextraction

A method of GC-MS coupled with dispersive liquid-liquid microextraction (DLLME) was developed for simultaneous and rapid determination of 24 pesticides in fish pond water. 1.0 mL of ethanol and 30 μL of tetrachloroethylene was rapidly added into 5.00 mL of sample to form emulsion. The mixture was let stand for 5 min, and centrifuged at 4 000 r·min^-1 for 5 min. The organic phase was separated on a VF-5MS capillary chromatographic column. EI and SIM were adopted in MS analysis. Linear relationships were found between the peak area and the mass conctentration of 24 pesticieds in definite ranges, with detection limits (3S/N) in the range 0.33-7.45 μg·L^-1. Recovery rates obtained by standard addition method ranged from 72.4% to 103% and RSDs (n=6) were in the range of 1.7%-13%. The poposed method was successfully applied to the detection of endosulfan-α, endosulfan-β and fenpropathrin in fish pond poisoning cases.