DLLME coupled with HPLC-DAD for enrichment of pesticide residues in environmental sediment and soil samples

Abstract

Sample pre-treatment during determination of pesticides in sediment and soil is difficult due to matrix effects. For this reason, a low density dispersive liquid-liquid microextraction (ld-dllme) was developed for the determination of carbaryl, cynazine, atrazine, and propazine. The experimental parameters that could potentially influence performances of the developed analytical technique including the extraction solvent type and volume, disperser solvent type and volume, extraction and centrifugation time, centrifugation speed, salt concentration, and pH were optimized. The optimum experimental values were found to be 50 mL 1-octanol, 0.6 mL acetonitrile, 5 min extraction time, centrifugation at 3500 rpm for 3 min, 10% NaCl and pH 5. At the optimum conditions, the methods offer good linearity (R2 = 0.998–0.999) for the concentration ranges of 30-800 µg/kg; the detection limit (lod) ranging from 9-24 µg/kg; precision <5.3% rsd, and reproducibility 0.5-5.2% rsd. The accuracy of the method, determined in terms of recovery was found to vary from 74.5-109.7%. Therefore, the developed analytical method could be used for the determination of trace level of pesticides residues in sediment and agricultural soil samples.