LAUSR

BACKGROUND Pesticides are extensively used worldwide to control plant pathogens and prevent agricultural product damage. However, they can pollute the environment and endanger human health. So far, a variety of sample preparation methods have been developed for pesticide residues analysis. RESULTS A hyphenated solid-liquid microextraction method based on a new magnetic graphene oxide functionalized by (3-glycidyloxypropyl)trimethoxysilane (GPTMS@MGO) adsorbent and a deep eutectic solvent (choline chloride/4-chlorophenol (1:2)) was developed for extraction/preconcentration of trace levels of pesticides. The sorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and vibrating sample magnetometer techniques. In-syringe magnetic dispersive solid phase extraction in tandem with dispersive liquid-liquid microextraction followed by gas chromatography was applied for the analysis of the selected pesticides. The main parameters governing sample preparation efficiency, including adsorbent dosage, desorption conditions, pH, extraction time, deep eutectic solvent volume, and salt concentration, were investigated. The linear ranges were 0.024-500 μg L-1 with 0.9971-0.9999 linearity factor (R2 ). The limits of detection and quantification were 0.006-0.038 and 0.024-0.126 μg L-1 , respectively. The relative standard deviations were 0.5-4.2% for intra-day analysis and 2.7-4.6% for inter-day analysis. Enrichment factors were in the range of 210-540. CONCLUSION The method was successfully applied for the determination of malathion, heptachlor epoxide, endrin, dichlorodiphenyltrichloroethane, azinphos ethyl, cypermethrin, and deltamethrin in fruit juice samples (apple, pineapple, cherry, peach, red, and green grapes juices) and the recoveries were within the 71-115% range. This article is protected by copyright. All rights reserved.