Partition of polyhydroxy compounds of biological and pharmacological significance between AOT reverse microemulsions and aqueous salt solutions

Abstract

AbstractThe partition behavior of shikimic acid, gallic acid, gallotannic acid, rutin and quercetin between reverse microemulsions of the surfactant bis(2‐ethylhexyl) sulfosuccinate (AOT) and aqueous salt solutions of LiCl, NaCl and KCl at different salt concentrations and pH was studied. Quantification of the extracted analytes was performed by HPLC on an octadecyl silica column using a methanol–buffer mobile phase at pH 3.0. Clean‐up before injection was not needed because the micellar organic phase was compatible with the HPLC mobile phase. A solvent gradient was used to elute all compounds and the surfactant in a reasonable time. The extraction from the aqueous media is fast and reproducible. Different solubilization behavior was observed by changing the salt concentration and the type of cation in the aqueous phase. By proper selection of the experimental conditions, it is observed that shikimic acid and gallic acid remain mostly in the aqueous phase, whereas significant amounts of gallotannic acid and rutin are transferred to the micellar phase in only one contact and quercetin is completely solubilized in this phase. Thus, the different solubilization behavior that these compounds exhibit in the AOT micellar media can be very useful for extraction and preconcentration purposes. Copyright © 2006 John Wiley & Sons, Ltd.