A green alternative QuEChERS developed based on green deep eutectic solvents coupled with gas chromatography-mass spectrometry for the analysis of pesticides in tea samples

Abstract

A novel green modified QuEChERS based on green deep eutectic solvents (DES) followed by GC–MS was developed to analyze pesticides in tea samples. Among different tested DESs for the extraction of analytes, ChCl:PEG (1:4) DES showed the highest efficiency. Three-dimensional magnetic graphene was functionalized by ChCl:urea (1:2) natural DES, characterized and used as sorbent in the in-syringe dispersive micro-SPE to cleanup tea extract. Under optimized conditions, linear range was 0.70–500 μg kg−1. The limits of quantification (0.70–1.90 μg kg−1) were lower than the maximum residue levels established by the European Union for pesticides in tea (0.015–0.1 mg kg−1). The method was applied to detect pesticides in green and black teas, and the recoveries were 70.2–105.2%. This work represents the first application of ChCl:PEG DES and 3DGA-Fe3O4/ChCl:urea in extraction of pesticides and tea sample cleanup, respectively. The greenness of procedure was evaluated by Analytical Eco-Scale and Complementary Green Analytical Procedure Index.