Extraction of benzoylurea pesticides from tea and fruit juices using deep eutectic solvents

In this study, low-density deep eutectic solvent combined with dispersive liquid-liquid microextraction was applied to the extraction of five benzoylurea insecticides (BUs, including diflubenzuron, triflumuron, hexaflumuron, flufenoxuron, and chlorfluazuron) from beverages. Then the extracted and concentrated samples were analyzed and detected using the high-performance liquid chromatography combined with an ultraviolet detector. The DESs were synthesized by [P14,6,6,6]Cl as hydrogen bond acceptor and tetradecyl alcohol as hydrogen bond donor, and then characterized by Fourier transform infrared spectroscopy. In the experiment, the key factors affecting the extraction efficiency were screened by Plackett-Burman design and optimized with the central composite design. The extraction recovery rates were 85.91-95.12%. The limits of detection and correlation coefficients of the method were 0.30-0.60 μg L^-1 and 0.9992-0.9997. Finally, the method was applied to determine the BUs in four beverage samples, and satisfactory recoveries, within the range of 76.87-101.19% were achieved. The present method has the potential to be applied to the detection of BUs in aqueous samples.