Hollow Fiber-Based Liquid Phase Microextraction Combined with High Performance Liquid Chromatography for Determination of Flavonoids in Ginkgo biloba and Urine

A hollow fibre membrane-based liquid phase microextraction (HF-LPME) method for determination of flavonoids in Ginkgo biloba leaves was developed. Three flavonoids: quercetin, kaempferol, and isorhamnetin were extracted and then analysed by high performance liquid chromatography. The factors affecting HF-LPME, including concentration of donor and acceptor phases, concentration of NaCl, extraction time. and stirring speed were systematically investigated. Under the optimum conditions, calibration plots of reasonable linearity were constructed in the analyte's concentration range of 10-100 mu g L-1. Up to 200-fold enrichment factor for quercetin and up to tens of folds for kaempferol and isorhamnetin were obtained. The method was applied to determine the concentrations of flavonoids in urine and was proven to be an convenient sample preparation technique.