Development of experimental design and chromatographic techniques to optimise the chemical analysis of ginseng, ginkgo biloba and other Chinese medicines

Abstract

Chromatographic technique is one of the most common analytical methods applied in many fields of Chemistry. In the past decade, the rapid improvement of computer technology and the image analysis technique enhance the development of chromatography to become a more accurate, advanced and user-friendly method in this century. In this research, the image analysis technique was applied to thin-layer chromatography for quantitative analysis of different Chinese medicines and optimization software was developed to help the HPLC users to improve the sample separation in high performance liquid chromatography. New quantitative method for two-dimensional (2D) thin-layer chromatography (TLC) was proposed in this project. The determination of intensity volume for TLC spots improved the performance in quantification and the suggested internal standard method was demonstrated to be effective in normalizing different staining effects of the TLC plates for detection. The proposed method was applied to the chemical analysis of different Panax Ginseng samples. Its performance was evaluated by conventional chromatographic methods. The experimental results showed that it was satisfactory to apply this high resolving chromatographic technique to other Chinese medicines with high complexities of sample matrix. Besides, a low-cost systemic method was also set-up for the quantitative analysis of another Chinese medicine, Ginkgo Biloba Leaves. The results obtained was useful for the development of standardized chemical analysis monograph of this herbal medicine in future. In addition, the optimization method LC-EASY was developed and was coded in this project. The method is based on the modified overlapping resolution mapping method (ORM) and was applied to optimize the mobile phase compositions of reversed-phase high performance liquid chromatographic separation. Finally, some suggestions were made for the above investigations.