Rapid and Direct Microextraction of Pesticide Residues from Rice and Vegetable Samples by Supramolecular Solvent in Combination with Chemometrical Data Processing

In this work, a rapid, simple, and environmentally friendly method has been proposed for direct supramolecular microextraction of four organophosphate insecticides (ethion, phosalone, diazinon, chlorpyrifos) and an isothiazolidine acaricide (hexythiazox) in agricultural product samples prior to their determination by high-performance liquid chromatography-ultraviolet spectroscopy. These five target pesticides have been selected as models in combination with chemometrical optimization processing due to their high consumption in rice, cucumber, and tomato samples for pest control. Method is based on the extraction of pesticide residues from homogenized food sample in an aqueous media containing some tetrahydrofuran (THF) and decanoic acid (DeA). Effects of the experimental parameters, including THF volume, DeA content, salt concentration (as a measure of salting-out effect), and pH on extraction recoveries (ERs) and enrichment factors (EFs) were investigated and, then, the significant variables were optimized using central composite design (CCD) as chemometrical processing. At optimum conditions, this method has a linear response over the ranges of 0.10 to 1500 μg kg−1 for target analytes. Limits of detection (LOD) of this method were found to be in the range of 0.05 to 0.20 μg kg−1. Also, relative standard deviation (RSD) of the method was in the range of 3.45 to 12.27% and the enrichment factors ranged from 102- to 178-fold. The method was applied successfully for analysis of the pesticides in agricultural product samples.