Determination of isoquercitrin in rat plasma by high performance liquid chromatography coupled with a novel synergistic cloud point extraction

A novel improved preconcentration method known as synergistic cloud point extraction was established for isoquercitrin preconcentration and determination in rat plasma prior to its determination by high performance liquid chromatography. Synergistic cloud point extraction greatly simplified isoquercitrin extraction and detection. This method was accomplished at room temperature (about 22 °C) in 1 min with the nonionic surfactant Tergitol TMN-6 as the extractant, n-octanol as cloud point revulsant and synergic reagent. Parameters that affect the synergistic cloud point extraction processes, such as the concentrations of Tergitol TMN-6, volume of n-octanol, sample pH, salt content and extraction time were investigated and optimized. Under the optimum conditions, the calibration curve for the analyte was linear in the range from 5 to 500 ng mL−1 with the correlation coefficients greater than 0.9996. Meanwhile, limit of detection (S/N = 3) was less than 1.6 ng mL−1 and limit of quantification (S/N = 10) was less than 5 ng mL−1. It demonstrated that the method can be successfully applied to the pharmacokinetic investigation of isoquercitrin.