Ion-pair dispersive liquid–liquid microextraction solidification of floating organic droplets method for the rapid and sensitive detection of phenolic acids in wine samples using liquid chromatography combined with a core–shell particle column

This study describes a novel sample preparation method for extraction of phenolic acids from wine using ion pair dispersive liquid–liquid microextraction based on the solidification of a floating organic droplet (IP-DLLME-SFO). The ion-pairing technique combined with DLLME-SFO dramatically enhanced the extraction efficiency for very polar phenolic acids, such as gallic acid and protocatechuic acid, which could not be extracted by DLLME-SFO in the absence of an ion-pairing reagent. The effects of the parameters that can affect the extraction efficiency were systematically investigated, including the type and concentration of ion-pairing reagent, type and volume of extraction and dispersive solvents, extraction time, sample pH, and ion strength. The method linearity was constructed in the range of 0.01–15 μg/mL, and the sensitivity expressed as limit of detection was as low as 10 ng/mL. The method that we developed was applied for the analysis of commercial wine samples, revealing different levels of phenolic acids among these products.