中药的采收季节与药物质量有着密切的关联, 研究不同季节采收药材的差异并对其进行准确识别, 对中药药理研究与质量控制意义重大。 采用红外光谱三级鉴别法, 对春季和秋季采收的黄芩进行研究。 结果表明, 春季与秋季采收的黄芩红外光谱吸收峰位置较相似, 但是酯类化合物中羰基CO的1 740 cm-1特征吸收峰, 黄酮类成分1 614 cm-1附近特征吸收峰及糖类成分1 071 cm-1附近吸收峰的相对峰强度差别显著。 通过二者相对峰强度的不同发现春季采收的黄芩药材中黄酮类和酯类成分高于秋季采收的药材。 比较二者在1 300～400 cm-1波数范围内的二阶导数红外光谱, 得出其所含糖类物质有所不同。 二者的差异在二维相关红外光谱上更加直观显著。 对16个批次的春季与秋季采收黄芩药材红外光谱进行了主成分分析, 结果表明二者可以得到准确区分。 综上, 红外光谱三级鉴别法与主成分分析相结合, 可以准确鉴别春季和秋季采收的黄芩, 并分析其化学成分的差异。

In the present paper, a tri-step infrared (IR) spectroscopy was used to study Scutellaria baicalensis Georgi (SBG) harvested in spring and autumn. The positions of peaks in the IR spectra of SBG harvested in spring and autumn were rather similar. However, according to the differences in the relative intensities of those characteristic peaks which include the ester carbonyl CO absorption peak at 1 740 cm-1, the peak near 1 614 cm-1 assigned to the flavonoids, and the peak near 1 071 cm-1 assigned to the carbohydrates, the amount of flavonoids and esters of spring SBGs was higher than that of autumn SBGs. Their carbohydrates were different by comparing the second derivative infrared spectra in the range of 1 300～400 cm-1. Furthermore, the above differences were visually validated by two-dimensional correlation spectroscopy(2D-COS). Moreover, the FTIR spectra of 16 batches of SBG harvested in spring and autumn were analyzed with principal component analysis, and subsequently they were exactly identified and classified. Therefore, tri-step identification of IR spectroscopy combined with principal component analysis can be employed to fast and accurately identify the SBG harvested in spring and autumn and differentiate the differences of their chemical constituents.