Combining QuEChERS extraction method and dispersive liquid– liquid microextraction as an efficient sample preparation approach for extraction of pesticides from fruit and vegetable samples

In this study, a combination of Quick Easy Cheap Effective Rugged and Safe extraction and dispersive liquid– liquid microextraction has been used for the extraction and preconcentration of some widely used pesticides (diazinon, chlorpyrifos, penconazole, oxadiazon, and diniconazole) from fruit and vegetable samples prior to their determination by gas chromatography–flame ionization detection. In this method, firstly, an aliquant of sample is crushed and its refuse and juice are separated by centrifuging. The juice is transferred to a conical glass test tube. Then acetonitrile as an extraction/disperser solvent is added into the tube containing refuse. The analyte residues are extracted into acetonitrile after vortexing. The obtained acetonitrile is mixed with an extraction solvent (1, 2–Dibromoethane) and rapidly injected into the juice. By this action, a cloudy state is formed and the tiny droplets of the extractant containing the extracted analytes are collected at the bottom of test tube after centrifugation. Finally, an aliquot of the sedimented organic phase is removed and injected into the separation system for quantitative analysis. Several significant factors affecting the performance of the introduced method were investigated and optimized. Under the optimum experimental conditions, extraction recoveries ranged from 48–75%. The relative standard deviations were ≤ 7% for intra– (n=6) and inter–day (n=4) precisions at a concentration of 100 μg L–1 of each analyte. Limits of detection were in the range of 0.27–0.48 μg L–1 in solution. Finally, the applicability of the proposed method was evaluated by analysis of the analytes in different fruit and vegetable.

کلیدواژه ها:

Quick Easy Cheap Effective Rugged and Safe method ، Dispersive liquid–liquid microextraction ، Fruit and vegetable ، Pesticide ، Gas chromatography