二维相关红外光谱法与黄芪及其伪品刺果甘草的分析与鉴定

采用红外光谱的三级鉴定法分析鉴别了黄芪及其伪品刺果甘草。在一维红外光谱中，刺果甘草的1 737 cm-1CO伸缩振动峰，明显高于黄芪的1 737 cm-1特征峰，说明刺果甘草含有机酯类化合物的量相对高于黄芪。在高分辨的二阶导数谱中，刺果甘草有明显的1 620，1 317，782和516 cm-1的草酸钙特征峰，而黄芪没有。此外，两者都存在1 463，1 511和1 596 cm-1的芳香类化合物的特征峰，不同的是刺果甘草的1 468 cm-1峰的右侧还有一个1 453 cm-1的小肩峰。在二维相关红外光谱中，两者都存在1 070，1 095和1 140 cm-1的糖苷类化合物的自动峰，不同的是黄芪的1 140 cm-1的自动峰强度最大，但刺果甘草的1 090 cm-1自动峰强度最大。谱图的三级鉴定验证了黄芪及其伪品刺果甘草在糖苷类化合物、芳香类化合物和有机酯类化合物的相对含量上都是不一致的。该方法不仅可以快速有效地鉴别黄芪及其伪品刺果甘草，还提供了两者的有机酯类化合物以及芳香类和糖苷类化合物具有很大差别的一些有用的结构信息。因此，运用红外光谱法可以快速有效地分析和鉴定黄芪及其伪品刺果甘草。

Analysis and Identification of Huangqi and Its Counterfeit Ciguogancao by Two Dimensional Corrlation Infrared Spectroscopy

Standard Huangqi (Astragalus membranaceus (Fisch) Bge. Var. monghlicus (Bge.) Hsiao) and its counterfeit Ciguogancao (Glychrrhiza pallidiflora Maxim.) can be discriminated and identified by using multi-steps infrared maro-fingerprint method. In the 1D-IR spectra, the peak intensity at 1 737 cm-1 for Ciguogancao, which is the stretching vibration peak of CO, is much stronger than that of Huangqi. It’s proved that the organic ester compounds in Ciguogancao are much more than Huangqi. In the secondary derivative spectra, it’s easy to find the fingerprint characteristic peaks of CaC2O4 in the infrared spectra of Ciguogancao, but not in that of Huangqi. Besides, both secondary derivative spectra also have main characteristic peaks, which are the skeletal stretching of aromatic, round 1 463, 1 511 and 1 596 cm-1, but Ciguogancao aslo has one shoulder peak at 1 453 cm-1. In the 2D-IR spectra, both have three auto-peaks at 1 070, 1 095 and 1 140 cm-1, which are the auto-peaks of glucoside, but the strongest auto-peak of Huangqi is at 1 140 cm-1 and that of Ciguogancao’s is at 1 090 cm-1. The spectra testified that the organic ester compounds, aromatic compounds and glucoside compounds in Huangqi and its counterfeit Ciguogancao were different. The method not only can identify standard Huangqi and its counterfeit Ciguogancao rapidly, but also provides useful information about the differences in organic ester compounds, aromatic compounds and glucoside between Huangqi and its counterfeit Ciguogancao. It’s proved that multi-steps infrared maro-fingerprint method can be used to analyze and distinguish Huangqi and its counterfeit Ciguogancao.