HPLC Determination of Buprofezin and Pyridaben in Water Samples with Separation by Dispersion Liquid-Liquid Microextraction

Two insecticides, buprofezin (BPFZ) and pyridaben (PRDB) were separated from water sample by mixing thoroughly with a mixture containing CH3CN and CHCl3 and standing for 5 min in a centrifuge tube. After centrifuging for 5 min, the solvent CHCl3 was removed by evaporation under reduced pressure and the residue was taken up with 50 μL of mixed solvent of CH3CN and water (75+25), from which an aliquot of 20 μL was taken for HPLC analysis. Symmetry C18 column was used as stantionary phase and mixture of CH3CN and water (75+25) as mobile phase. UV detection at 238 nm was adopted in the determination. Linearity ranges were found between 2.0-100 μg·L-1 (for BPFZ) and 1.0-100 μg·L-1 (for PRDB). Values of recovery and RSD′s (n=5) found were in the ranges of 81.2%-99.2%, 87.3%-100.7%, and 1.7%-8.3%, 0.6%-9.1% respectively.