Development of a dispersive liquid–liquid microextraction method based on solidification of a floating ionic liquid for extraction of carbamate pesticides from fruit juice and vegetable samples

Abstract

In this work, a simple, inexpensive, reliable, and environmentally friendly sample preparation method based on solidification of an ionic liquid after performing dispersive liquid–liquid microextraction has been developed for the extraction and preconcentration of four carbamate pesticides (carbofuran, methiocarb, carbaryl, and thiodicarb) followed by their determination with high performance liquid chromatography-diode array detector. For this purpose, a secondary amine is mixed with a carboxylic acid to prepare an ionic liquid with a low melting point. Then, the prepared ionic liquid is used as an extraction solvent in the microextraction procedure. The effect of different parameters that can affect the extraction efficiency of the developed method was systematically investigated. Under optimum conditions low limits of detection and quantification in the ranges of 0.32–0.51 and 1.09–1.72 ng mL⁻¹, respectively, were obtained. Enrichment factors and extraction recoveries were obtained in the ranges of 173–227 and 69–91%, respectively. Finally, the proposed method was successfully used in the determination of the selected carbamate pesticides in some fruit juice and vegetable samples at ng mL⁻¹ level.