Three-dimensional characteristic chromatogram by online comprehensive two-dimensional liquid chromatography: Application to the identification and differentiation of ginseng from herbal medicines to various Chinese patent medicines

One bottleneck problem in the quality control of traditional Chinese medicine (TCM) is the accurate identification of easily confused herbal medicines from Chinese patent medicine (CPM). Ginseng prod-ucts derived from the multiple parts (e.g., root/rhizome, leaf, and flower bud) of multiple Panax species (P. ginseng, P. quinquefolius, P. notoginseng, P. japonicus, and P. japonicus var. major ) are globally popular; however, their authentication is very challenging. Using online comprehensive two-dimensional liquid chromatography (LC x LC), we propose the concept of a three-dimensional characteristic chromatogram (3D CC) by integrating enhanced LC x LC separation and a contour plot that visualizes the stereoscopic chromatographic peaks and examine its performance in authenticating various ginseng products. Targeted at the resolution of 17 ginsenoside markers, an online LC x LC/UV system with a 56 min analysis time was constructed: a CORTECS UPLC Shield RP 18 column running at 0.1 mL/min for the first-dimensional chromatography and a Poroshell SB-Aq column at 2.0 mL/min in shift gradient mode in the second di-mension of separation. In particular, ginsenosides Rg1/Re and Rc/Ra1 were well resolved. According to the presence/absence of stereo peaks consistent with the main ginsenoside markers in the 3D CC and the depth of shade (depending on peak volume), it was feasible to use a single method to identify and dis-tinguish among 12 different ginseng species as the drug materials and the use of ginseng simultaneously from 21 CPMs. Conclusively, a practical solution enabling the accurate identification of easily confused TCMs was provided, covering both the drug materials and the compound preparations.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

We propose the concept of a three-dimensional characteristic chromatogram (3D CC) and use it to authenticate various ginseng products through online comprehensive two-dimensional liquid chromatography (LC x LC) technology. By analyzing the stereo peaks and shade depth in the 3D CC, it is feasible to identify and distinguish different ginseng species and Chinese patent medicines. This provides a practical solution for the accurate identification of easily confused traditional Chinese medicines (TCMs).