Development of a new temperature-controlled liquid phase microextraction using deep eutectic solvent for extraction and preconcentration of diazinon, metalaxyl, bromopropylate, oxadiazon, and fenazaquin pesticides from fruit juice and vegetable samples followed by gas chromatography-flame ionization detection

Abstract

In the present study a liquid phase microextraction method has been developed using new kind of solvents named deep eutectic solvents, for the extraction and preconcentration of some pesticides from different samples including apple, grape and sour cherry juices and fresh beet, cucumber, potato, and tomato. In this work, a deep eutectic solvent has been synthesized using a hydrogen bonding donor (p–chlorophenol) and hydrogen bonding acceptor (choline chloride), then used as an extraction solvent. Dispersion of the extraction solvent into the aqueous phase was performed by temperature changing. Dispersion of deep eutectic solvent had dramatically enhanced by the developed method which led to the improvement of extraction efficiency of the method. Under the optimum extraction conditions, enrichment factors and extraction recoveries were obtained in the ranges of 280–465 and 56–93%, respectively. Low limits of detection and quantification were obtained in the ranges of 0.13–0.31 and 0.45–1.1 ng mL−1, respectively. Relative standard deviations were less than 9%, for the extraction of 50 ng mL−1of each pesticide which obtained for intra- (n = 6) and inter-day (n = 4) precisions. Application of the method on the studied samples were free of the analytes, except tomato in which diazinon was detected at a concentration of 62 ng g−1.