Deep eutectic solvent-based emulsification liquid–liquid microextraction coupled with gas chromatography for the determination of thiophenols in water samples

摘要

A simple, fast, cheap, and effective method named deep eutectic solvent-based emulsification liquid–liquid microextraction (DES-ELLME) was employed to extract thiophenols from water samples. DES was characterized by Fourier transform-infrared (FT-IR) spectroscopy, CHN elemental analysis, and proton and carbon nuclear magnetic resonance spectroscopies (1H-NMR and 13C-NMR). 50 μL DES was added to the aqueous sample solution and a uniform solution was formed immediately. After injection of 50 μL acetone into this solution, turbidity was observed. Then, the phase separation (DES rich phase/aqueous phase) was performed by centrifugation. DES rich phase was subjected to gas chromatography with a flame ionization detector (GC-FID). Significant factors including the volume of acetone and DES, ultrasonication time, and pH were combined using a desirability function (DF) and optimized through a Box–Behnken design. Calibration graphs were linear in the concentration range of 0.02–100 mg L?1 under optimum experimental conditions; the coefficients of correlation were more than 0.999. The limits of detection and quantification were in the ranges of 10–15 μg L?1 and 33–50 μg L?1, respectively. This method was used to determine target analytes in spiked water samples; the relative mean recoveries were 96 to 104%.