采用红外光谱法、 二阶导数红外光谱法和二维相关红外光谱法, 对桂林西瓜霜系列产品进行了快速无损比对分析研究。 结果表明, 同一生产厂家不同品种的西瓜霜在红外光谱上差异较显著, 所添加辅料的类型和含量有所不同。 在一维红外谱图上, 西瓜霜喷剂﹑西瓜霜胶囊在638和616 cm-1处有明显的硫酸钠的特征峰; 西瓜霜清咽含片﹑西瓜霜喉宝含片和西瓜霜润喉片的红外光谱中, 能明显地看到蔗糖、 糊精等辅料的特征峰, 其中西瓜霜润喉片的红外谱图与蔗糖的红外谱图非常相似, 说明西瓜霜润喉片中所添加的蔗糖较多。 而在二维红外谱图上, 由于五种西瓜霜的自动峰及相关峰峰簇的位置和数量和峰的相对强度的不同, 其差别体现得更为明显和直观。 应用红外光谱、 二阶导数红外光谱和二维相关红外光谱技术, 不仅可以提供西瓜霜系列产品主要化学成分的相关信息, 还可以对各产品所添加的辅料类型和含量进行分析和指认。 因此, 红外光谱法是考察中药资源的一种简便、 快速、 直观、 有效的方法。

The objective of the present study is to analyze different products of Guilin watermelon frost by Fourier transform infrared spectroscopy (FTIR), second derivative infrared spectroscopy and two-dimensional correlation spectroscopy (2D-IR) under thermal perturbation. The structural information of the samples indicates that samples from the same factory but of different brands had some dissimilarities in the IR spectra, and the type and content of accessories of them were different compared with conventional IR spectra of samples, peaks at 638 and 616 cm-1 all arise from anhydrous sodium sulfate in watermelon frost spray and watermelon frost capsule; the characteristic absorption peaks of the sucrose, dextrin or other accessories can be seen clearly in the spectra of watermelon frost throat-clearing buccal tablets, watermelon frost throat tablets and watermelon frost lozenge. And the IR spectra of watermelon frost lozenge is very similar to the IR spectra of sucrose, so it can be easily proved that the content of sucrose in watermelon frost lozenge is high. In the 2D-IR correlation spectra, the samples presented the differences in the position, number and relative intensity of autopeaks and correlation peak clusters. Consequently, the macroscopical fingerprint characters of FTIR, second derivative infrared spectra and 2D-IR spectra can not only provide the information about main chemical constituents in medical materials, but also analyze and identify the type and content of accessories in Guilin watermelon frost. In conclusion, the multi-steps IR macro-fingerprint method is rapid, effective, visual and accurate for pharmaceutical research.