The nonanol/surfactant directed self-assembly supramoleculars heat-shrinkable tubing liquid phase microextraction for determination of flavonoids in natural products combined with high performance liquid chromatography

In this paper, a supramolecular heat-shrinkable tubing liquid phase microextraction was developed for the enrichment and determination of flavonoids. The nonanol adsorbed by the heat-shrinkable tubing could induce the surfactant in aqueous solution to self-assembly on its surface, and formed nonanol/CTAB supramolecules in a directional arrangement. The supramolecules structure enhanced the enrichment efficiency of five flavonoids. The parameters affecting the extraction efficiency were optimized, such as the type of organic solvent, concentration of surfactant, pH and volume of sample phase, salt concentration of sample solution, stirring speed and extraction time. The methodological investigation was carried out under the optimal experimental conditions. The enrichment factors of the five analytes were between 72.3 and 93.3. The concentrations of the target analytes showed good linearity between 0.2 and 5 µg/mL, 0.01–1 µg/mL, 0.01–5 µg/mL, respectively. The limit of detection was no more than 25 ng/mL. The procedure was successfully applied in extraction of five flavonoids from the natural products according to its average recoveries of 98.3–101.7 %.