Determination of Chlorogenic Acid in Flos Lonicerae Japonicae via Dynamic Microwave-assisted Extraction Coupled On-line with High-performance Liquid Chromatography

A fast method based on dynamic microwave-assisted extraction(DMAE) coupled on-line with high-performance liquid chromatography(HPLC) by means of a flow injection interface has been developed for the determination of chlorogenic acid in Flos Lonicerae japonicae. The extraction was performed in a recirculating system.When a number of extraction cycles were completed,the fractional extract(20 μL) was driven to the analytical column by mobile phase and was measured by a UV detector.The extraction conditions were examined and optimized.The detection and quantification limits of chlorogenic acid obtained at optimized conditions are 0.25 and 0.83 μg/mL,respectively.The intra-day and inter-day precisions(RSD) obtained are 3.4% and 4.1%,respectively.The mean recovery of chlorogenic acid is 98.1%.Compared with ultrasonic extraction used in the Chinese pharmacopoeia,the proposed method reduces the amount of solvent, provides more rapid measurement and high extraction yield.