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

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.