Optimization of an ultrasound-assisted alcohol-based deep eutectic solvent dispersive liquid-phase microextraction for separation and preconcentration of quercetin in wine and food samples with response surface methodology.

We optimized ultrasound-assisted alcohol-based deep eutectic solvent dispersive liquid-phase microextraction for separation and preconcentration of quercetin in wine and food samples by experimental design based on central composite design. Five different alcohol-based deep eutectic solvents were prepared and tested for quercetin extraction. The effect of important parameters and matrix components were optimized. After optimization, the determination of quercetin was performed at 385 nm using spectrophotometry. Analytical data such as detection limit, working range and preconcentration factor were found as 6.1 μg/L, 20-850 μg/L, and 120, respectively. The selectivity of the optimized extraction conditions for quercetin was investigated in the presence of different matrices. The validation of the method was investigated by reproducibility, repeatability and recovery studies, as well as by comparing the analytical results obtained from real samples with the reference method. Lastly, the recommended procedure was successfully applied for the extraction and quantification of quercetin in wine and food samples.