A Novel Deep Eutectic Solvent-Based Ultrasound-Assisted Dispersive Liquid–liquid Microextraction Coupled with High-Performance Liquid Chromatography for the Determination of Quinolones in Environmental Water Samples

In this work, a novel deep eutectic solvent composed of thymol and octanol was synthesized and employed as a green extractant for ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) of three quinolones in environmental water followed by HPLC-UV analysis. Parameters affecting UA-DLLME were investigated and optimized. The optimal DES ratio was 2:1, the volume was 150 mu L, ultrasonic time was 5 min, and the NaCl concentration was 0.68 mol center dot L-1. Good linearity was obtained over the concentration range of 1-100 ng center dot mL-1 with R2 >= 0.9986. The limits of detection (LOD) were 0.1-0.3 ng center dot mL-1 and the limits of quantification (LOQ) were 0.4-1.0 ng center dot mL-1 with RSD less than 4.8%. The method was fast, sensitive and eco-friendly, which offered a new way to monitor quinolone levels in environmental water.