Salt-saturated supramolecular solvent-assisted dispersive liquid-liquid microextraction for the efficient enrichment and determination of resveratrol in water and grape juice

A salt-saturated supramolecular solvent–assisted dispersive liquid–liquid microextraction (SUPRAS-SS-DLLME) method was developed for the efficient enrichment and spectrophotometric determination of resveratrol in water samples, and grape juice. The extraction strategy is based on the self-assembly of amphiphilic molecules into supramolecular solvent architectures, whose extraction capability is significantly enhanced by a salt-induced reduction of analyte solubility in the aqueous phase.

A mixture of NaCl, Mg(NO₃)₂·6H₂O, and KNO₃ was employed to achieve salt saturation, resulting in an average enhancement of extraction efficiency of approximately 30% compared to salt-free conditions. Key experimental parameters affecting the extraction process, including pH, extraction solvent volume, and disperser solvent volume, were systematically optimized using response surface methodology. Under optimal conditions, the method exhibited a linear response in the concentration range of 10–5000 µg/L with a correlation coefficient (R²) of 0.9962. The limit of detection and limit of quantification were 1.6 and 5.3 µg/L, respectively, with an enrichment factor of 124. The method demonstrated good precision (RSD < 4.4%) and excellent recoveries (97.3–99.9%).

The proposed SUPRAS-SS-DLLME method requires low solvent volumes, short extraction time (< 10 min), and competitive LOD for spectrophotometric detection, in accordance with green analytical chemistry principles. The method was successfully applied to the determination of resveratrol in tap water, wastewater, and red and green grape juice samples, demonstrating its reliability and potential for routine analysis of bioactive compounds in complex matrices.