DETERMINATION OF CHLORPYRIFOS AND ITS MAIN DEGRADATION PRODUCT TCP IN WATER SAMPLES BY DISPERSIVE LIQUID-LIQUID MICROEXTRACTION BASED ON SOLIDIFICATION OF FLOATING ORGANIC DROPLET COMBINED WITH HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

This article reports an alternative method for simultaneous extraction and determination of chlorpyrifos and its main degradation product 3,5,6-trichloro-2-pyridinol (TCP) in water samples which involves dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by high-performance liquid chromatography with ultraviolet detection. Methanol (1.0mL) and 1-dodecanol (70 mu L) were used as the disperser solvent and extraction solvent, respectively. After the floated extraction solvent had solidified in an ice bath, it was dissolved with methanol. Under the optimized conditions, enrichment factors for chlorpyrifos and TCP were 96 and 114, respectively. Linear calibration curves were obtained in the range of 1-50 mu gL (-1), with correlation coefficients (R (2))>0.9955. The limits of detection were 0.12 mu gL (-1) for chlorpyrifos and 0.10 mu g L (-1) for TCP. The recoveries of spiked real water samples ranged between 84.54% and 102.29%, with the relative standard deviation being 0.80-14.03%.