[Optimization of high performance liquid chromatographic method for analysis of kudzu root crude extract]

Kudzu root is an important traditional Chinese herb. Its crude extract has been used in the treatment of hypertension and angina pectoris in China. Several parameters for high performance liquid chromatography (HPLC) analytical method for kudzu root extract, including HPLC model, mobile phase, additive and gradient conditions have been optimized. The HPLC retention parameters a and c, and the peak shape parameters sigma and tau of 25 chromatographic peaks were obtained accurately and rapidly using five linear gradients and were calculated using CSASS software. The CSASS software was then used to simulate the gradient conditions in the experiments, and the optimized condition was obtained. The comparison of the simulated and real chromatogram profiles showed that the potential of simulation using the CSSASS software as compared to that of the real experimental conditions was precise. Reversed-phase HPLC model and the mobile phase of (A) acetonitrile containing 0.1% (v/v) acetic acid and (B) water containing 0.1% (v/v) acetic acid were used. The optimized gradient profile showed a linear increase as follows: from 5% A to 35% A at 0 - 33 min; from 35% A to 100% A at 33 - 50 min, and then the HPLC system was held for 5 min. The reproducibility and precision of the method were investigated. The relative standard deviations (RSDs) of retention time, peak height, and peak area were less than 0.25%, 11%, and 4.9%, respectively, which showed that the method was stable, reliable, and reproducible.