Dispersive liquid-liquid microextraction method for the extraction of acidic pesticides in edible oils; application of short-chain organic acids as co-disperser and protonation agent

摘要

In the present study, a sample pretreatment based on the combination of vortex assisted liquid-liquid extraction and dispersive liquid-liquid microextraction has been proposed for the isolation and preconcentration of three acidic herbicides including fenoxaprop, fluazifop, and haloxyfop from edible oil samples. For this purpose, firstly, the analytes were extracted into sodium hydroxide solution (by deprotonating the analytes) which was used as a dispersive solvent in the following microextraction procedure. The obtained aqueous phase was mixed with acetic acid as a pH adjustment agent and co-disperser solvent. After the addition of dichloromethane (extraction solvent) to the above solution, it was quickly dispersed into deionised water. The validation parameters indicated that the limits of detection and quantification of the proposed method were in the ranges of 0.3-1.8 and 1.0-6.0 ng mL(-1), respectively. Relative standard deviations of the method were obtained in the range of 4.8-6.2 and 5.2-9.1 for intra - (n = 6) and inter-day (n = 5) precisions, respectively. High extraction recoveries and enrichment factors ranged from 74 to 91, and 185 to 227 were the other advantages of the method. These merits showed that the proposed method is efficient and sensitive for the determination of the studied analytes in the edible oil samples.