Simultaneous preconcentration and determination of 2,4-D, alachlor and atrazine in aqueous samples using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography ultraviolet detection.

Dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography-ultraviolet detection as a fast and inexpensive technique was applied to the simultaneous extraction and determination of traces of three common herbicides, 2,4-D, alachlor and atrazine, in aqueous samples. The critical experimental parameters, including type of the extraction and disperser solvents as well as their volumes, sample pH, salt addition, extraction time and centrifuging time, and speed were investigated and optimized. Under the optimum conditions, the calibration graphs found to be linear in the range of 0.3-200 μg/L with limits of detection in the range of 0.05-0.1 μg/L. The relative standard deviations were in the range of 4.5-6.2% (n = 7). The relative recoveries of well, tap, and river water samples which have been spiked with different levels of herbicides were 92.0-107.0, 82.0-104.0, and 82.0-86.0%, respectively.