A lighter-than-water deep eutectic-solvent-based dispersive liquid-phase microextraction method in a U-shaped homemade device

Abstract

In this study, a new microextraction method, termed glass-filter-based dispersive liquid-phase microextraction using a lighter-than-water deep eutectic solvent, was developed for the extraction and preconcentration of different classes of pesticides, including dichlorvos, diazinon, simazine, prometryn, terbutryn, bifenthrin, fenpropathrin, bromopropylate, phosalone, and deltamethrin, from fruit juice and vegetable samples. In this method, a U-shaped homemade device with different diameters containing filter glass tubes was used as an extraction device. An aqueous sample solution containing the analytes was transferred into the device on top of the glass filter, and a lighter-than-water extraction solvent (ChCl:pivalic acid) was placed under the glass filter. The extraction solvent was passed through the glass filter with the aid of an air flow and interred into the aqueous solution. By this action, the extraction solvent was dispersed in the aqueous solution, and the analytes were extracted into the fine droplets of the extraction solvent. The produced droplets of the extraction solvent went up through the solution and were obtained without centrifugation. The enriched analytes were determined by gas chromatography-mass spectrometry. Under the optimum extraction conditions, the method showed low limits of detection and quantification in the ranges of 3–26 and 10–92 ng L⁻¹ in fruit juices and 10.0–16.9 and 35.0–59.8 ng kg⁻¹ in vegetable samples, respectively. Extraction recoveries and enrichment factors ranged from 79–96% and 263–319, respectively. Relative standard deviations of ≤8% for the extraction of 150 ng L⁻¹ of each pesticide were obtained for the intra- (n = 6) and inter-day (n = 5) precisions. Finally, different fruit juices and vegetable samples were successfully analyzed using the proposed method, and diazinon and bromopropylate were determined in some samples.