Development of QuEChERS method Combined with dispersive liquid-liquid microextraction for determination of some pesticides in cucumber samples using High-performance liquid chromatography

Abstract

Due to the widespread use of pesticides to protect agricultural products around the world and the accumulation of residues of these substances in plant tissue, most of the products that have been exposed to pesticides contain amounts of pesticide residues. The most popular and sensitive method for determining low amounts of pesticide residues in order to find out their maximum residue levels (MRLs) in food products is the chromatographic assay. In the present study, the diazinon, chlorpyrifos, imidacloprid, acetamiprid, thiacloprid and fenvalerate insecticides were extracted from cucumber samples by using QuEChERS method in combination with liquid-liquid microextraction and were determined by HPLC-DAD. For this purpose, the effective factors in the developed extraction method were optimized and the mentioned method was validated. Based on the results, the target analytes were successfully extracted simultaneously using 2 ml of a mixture of acetonitrile, methanol, and acetone (in the QuEChERS step). Further, the highest efficiency in the second extraction step was obtained using 65 µl of hexanol and 15% NaCl. The LOD between 0.36 and 0.57 ng/g, high repeatability in the range of 3.6 to 6.8 (based on the RSD%), and extraction recovery of analytes in the range of 76 to 84% of the developed method's merit figures indicate the method's high capability in extracting particular pesticides. Overall, the procedure described in this study is a simple and cheap method and has a good ability to extract the desired pesticides from cucumber samples.

Keywords

• cucumber
• insecticide
• high-performance liquid chromatography
• microextraction
• quechers