传统鉴别法和现代鉴别法是目前我国中草药检测领域的主要方法。 传统鉴别方法虽因简便、 成本低廉等优势在研究中被广泛采用, 但鉴别准确度在一定程度上依赖于操作者是否具备丰富的药材知识和经验。 随着光谱分析技术的发展, 基于光谱分析技术的现代鉴别法逐渐走入人们的视野。 理论及大量实验研究表明, 中草药代谢物分子内振动模式及晶格的低频振动均发生在太赫兹波段, 据此可以鉴别中草药中所含成分。 甘草酸是甘草中的主要成分, 选择甘草酸为研究对象, 运用量子化学计算方法模拟甘草酸的太赫兹吸收谱, 为甘草酸的太赫兹吸收特征匹配分子振动模式, 此项工作对于深刻理解甘草酸分子内部各基团的相互作用与谱的形成机理十分必要。 为了确保模拟结果的可靠性, 需要建立甘草酸分子的初始构型, 选择合适的计算方法进行结构优化和频率计算, 最终获取甘草酸的太赫兹吸收谱数据。 利用Gaussian09半经验理论的PM3算法计算得到甘草酸太赫兹特征吸收峰分别位于0.87, 1.17, 1.56与2.76 THz处, 其中1.56 THz处的特征峰与参考文献中实验所测结果完全一致, 验证了计算结果的可靠性。 由于每个甘草酸分子中含有120个原子, 体系庞大, 在做振转模式分析时无法呈现其完整的结构, 故采用甘草酸分子的平面结构代替立体结构进行太赫兹特征吸收峰的振转分析。 分析表明, 甘草酸分子的太赫兹特征吸收峰产生与含氧官能团以及碳环的振转有关, 但主要是由甘草酸分子中的含氧官能团扭转形成的。

Traditional identification method and modern identification method are the main methods in the field of Chinese herbal medicine detection. Although the traditional identification method is widely used in research because of its advantages such as simplicity and low cost, the accuracy of identification depends to some extent on whether the operator has rich knowledge and experience in medicinal materials. With the development of spectral analysis technology, modern identification methods based on spectral analysis technology have gradually entered people’s field of vision. Theoretical and a large number of experimental studies have shown that the intramolecular vibration mode of the Chinese herbal metabolites and the low-frequency vibration of the lattice occur in the terahertz band, which can be used to identify the components contained in the Chinese herbal medicine. Glycyrrhizic acid is the main component in licorice. Glycyrrhizic acid was selected as the research object. The terahertz absorption spectrum of glycyrrhizic acid was simulated by a quantum chemical calculation method. The terahertz absorption characteristic of glycyrrhizic acid matched the molecular vibration mode. This work is deeply understood. The interaction of various groups within the glycyrrhizic acid molecule and the formation mechanism of the spectrum are necessary. In order to ensure the reliability of the simulation results, it is necessary to establish the initial configuration of the glycyrrhizic acid molecule, select the appropriate calculation method for structural optimization and frequency calculation, and finally obtain the terahertz absorption spectrum data of glycyrrhizic acid. Through the Gaussian09 semi-empirical theory PM3 algorithm, the characteristic absorption peaks of the glycyrrhizic acid terahertz are located at 0.87, 1.17, 1.56 and 2.76 THz, respectively. The characteristic peak at 1.56 THz is exactly the same as the experimental results in the reference literature, verifying the reliability of the calculation results. Since each glycyrrhizic acid molecule contains 120 atoms, the system is so large that it cannot exhibit its complete structure when it is analyzed by vibration mode. Therefore, the planar structure of glycyrrhizic acid molecules is used instead of the three-dimensional structure to carry out the vibration of the terahertz characteristic absorption peak. Turn analysis. The analysis shows that the terahertz characteristic absorption peak of glycyrrhizic acid molecule is related to the oxygen-containing functional group and the ring-like vibration of the carbon ring, but is mainly formed by twisting of the oxygen-containing functional group in the glycyrrhizic acid molecule.