The extraction of pyrethroid insecticides in juice and tea beverages by liquid-phase microextraction using deep eutectic solvents

Deep eutectic solvents (DESs), which consist of a mixture of hydrogen bond acceptor and hydrogen bond donor compounds, were used in liquid-phase microextraction, in which the extractant was dispersed in a porous ceramic film for the determination of pyrethroid pesticides in juice and tea beverage samples. Factors affecting recovery were optimized individually, which included salt addition, surfactant addition, extraction temperature, DES amount and sample volume. Based on the results of an optimized experiment, the recovery of pyrethroid pesticides is from 87.5% to 97.2% with relative standard deviation (RSD) values ranging from 1.68% to 2.86%. Determination coefficient was from 0.9981 to 0.9997 and the linear range was between 1.5 μg L−1 and 500 μg L−1. Based on a signal-to-noise ratio (S/N) of 3 : 1, the limit of detection (LOD) values were 0.45 μg L−1 to 1.30 μg L−1. The enrichment factor ranged from 93 to 106. For real samples, bifenthrin is found in black tea (Gold rougui) and oolong tea (Tieguanyin2); etofenprox is also found in the oolong tea (Tieguanyin3). In spiked samples, good extraction efficiency was achieved for all types of samples analyzed under the optimized conditions.