Chromatographic Analysis of Paeonol in Natural Plants: an Undergraduate Laboratory Experiment for Comparative Observation of HPLC and GC Performance

Chromatography is a powerful technique for both qualitative and quantitative analysis in natural product investigation. There are different types of chromatographic methods, mainly gas chromatography (GC) and high-performance liquid chromatography (HPLC). Although many students have understood the basic principles of GC and HPLC, they often encounter challenges in effectively designing appropriate chromatographic methods to solve practical separation and detection problems. This is mainly due to their lack of hands-on experience to compare the differences regarding the performance of GC and HPLC. This laboratory experiment aims to address this issue primarily by comparatively observing the performance of GC and HPLC during the analysis of paeonol in the natural plant Moutan Cortex (MC). The aromatic group and low molecular weight of paeonol make it particularly suitable for both GC and HPLC analyses, rendering it an optimal choice of the analyte. This laboratory experiment includes paeonol extraction, GC/HPLC analysis of paeonol, and comparison of the performance of the two chromatographic methods, including column efficiency, retention times, limits of detection, quantitative methods, etc. Through the experiment, students are able to select appropriate GC/HPLC methods based on the requirements for analyzing paeonol: GC is suitable for high-sensitivity detection, while HPLC is more appropriate for a simple pretreatment process. The course aims to assist students in designing and applying chromatographic methods proficiently in the areas of pharmaceutical analysis, natural product analysis, and analytical chemistry.