SUSTAINABLE CHEMISTRY AND PHARMACY, vol.22, 2021 (SCI-Expanded)
Switchable-hydrophilicity solvent-liquid-liquid microextraction (SHS-LLME), as an efficient sample cleanup method, was combined with dispersive solid-phase microextraction (DSPME) for preconcentration of quercetin prior to its spectrophotometric determination. Optimum SHS-LLME were found as 1000 mu L of N,N-dimethylcy-clohexylamine as the extraction solvent and 750 mu L of 10.0 M sodium hydroxide as the phase separation trigger. Optimum DSPME were sample pH at 6.0, 1000 mu L of acetone as the eluent, 30.0 mL of sample, 12.5 mg of Fe 3 0 4 @XAD-16 as the adsorbent, 4.0 and 1.5 min as the adsorption and elution times, respectively. Calibration graphs with coefficient of determination (R-2) higher than 0.9956, limits of detection (LOD) of 9.0-11.9 ng mL(-1) and limits of quantitation (LOQ) of 29.9-39.6 ng mL(-1) were obtained. Repeatability, expressed as percentage relative standard deviation (%RSD), was better than 3.2 and 8.9% for intra- and inter-day precision, respectively. The proposed SHS-LLME-DSPME-UV/Vis method was applied for the determination of quercetin in four food samples (i.e., apple, pepper, red and white onion) with percentage recoveries in the range of 92.1-107.4%. The proposed method is superior to others in terms of greenness, rapidness, simplicity, good repeatability and low capital cost.