New low viscous hydrophobic deep eutectic solvents in vortex-assisted liquid-liquid microextraction for the determination of phthalate esters from food-contacted plastics.

In this work, a novel class of eight low viscosity hydrophobic deep eutectic solvents (DESs) has been designed and prepared from two kinds of quaternary ammonium salts and six kinds of water-insoluble fatty alcohols/acids. Several physical properties of these DESs, such as melting point, density and viscosity, have been determined to investigate their adaptability as solvents. Then, such DESs are used as extraction solvents in a vortex-assisted liquid-liquid microextraction for the extraction and preconcentration of phthalate esters (PEs) from water samples, and the content of PEs from food-contacted plastics is then determined by using gas chromatography. It is found that the analytic method developed in this work exhibits wide linear range of 5-1000 µg L, and the limit of detections for target analytes is as low as 1 µg L. Finally, the proposed method has been successfully used for the determination of PEs from food-contacted plastics.