利用SEM图和XRD指纹图谱鉴别矿物类中药生石膏与玄精石

Identification of Mineral Traditional Chinese Medicine Gypsum and Selenitum by SEM and XRD Fingerprint

目的:采用性状鉴别、理化鉴别等传统方法结合扫描电子显微镜(SEM)及粉晶X-射线衍射(XRD)等现代分析技术,对矿物类中药生石膏和玄精石进行系统鉴别。方法:采集生石膏和玄精石样品,记录原药材及其粉末性状特点,进行理化鉴别,确定样品真伪及品种。在上述基础上,采集各药材样品SEM显微图,对比生石膏与玄精石各显微图之间的差异,总结两者SEM鉴别特征;同时采集各样品粉末的XRD图谱,分别计算并绘制生石膏与玄精石的XRD平均图谱,确定共有指纹峰,并对共有指纹峰相对强度数据分别进行相似度评价、聚类分析和主成分分析(PCA),验证生石膏与玄精石的XRD共有指纹峰用于两者鉴别的可行性。结果:生石膏和玄精石碎屑的SEM特征具有差异,玄精石均呈疏松层片状堆叠,细小碎屑均成沙粒状;而生石膏呈紧密聚合的长纤维状,且细小碎屑或粉末具碎裂状纤维特征。生石膏和玄精石粉末的XRD图谱峰位相似,但玄精石各峰相对生石膏各峰略左移,相同峰位衍射峰的相对强度存在差异。相似度评价显示生石膏与玄精石明显分离,聚类分析及主成分分析均可将两者准确区分。结论:SEM和XRD技术均可准确鉴别生石膏和玄精石及其粉末,传统鉴别方法结合SEM和XRD分析技术能够为生石膏和玄精石及其粉末的快速鉴别和质量控制提供快速准确的新方法。

Objective: To systematically identify mineral traditional Chinese medicine gypsum and selenitum by traditional methods such as character identification,physical identification and chemical identification combined with modern analysis techniques such as scanning electron microscope( SEM) and powder crystal X-ray diffraction( XRD). Methods: The samples of gypsum and selenitum were collected,and then,the characteristics of the original medicinal materials and their powders were recorded. Physical and chemical identification were performed in order to determine the authenticity and variety of the samples. On this basis,SEM micrographs of each sample of medicinal materials were collected,and the differences between the micrographs of gypsum and selenitum were compared,and the SEM identification characteristics were summarized. At the same time,XRD patterns of each sample were collected. The average XRD patterns of gypsum and selenitum were collected and the common fingerprint peaks were determined. The similarity evaluation,cluster analysis and principal component analysis( PCA) were performed on the relative intensity data of the common fingerprint peaks to verify the feasibility of identification of gypsum and selenitum by XRD common fingerprint peaks.Results: The SEM characteristics of gypsum and selenitum were significantly different. Gypsum is stacked in loose layers and slabs,and the fine debris was sandlike,while gypsum was in the form of long fiber which was closely polymerized,and the small debris or powder had the characteristics of broken fibers. The peak positions of XRD patterns of gypsum and selenitum powder were similar,but the peaks of selenitum were slightly shifted to the left of gypsum,and the relative intensity of the peak at the same peak position was different. The similarity evaluation showed that gypsum and selenitum were clearly separated. Both cluster analysis and principal component analysis could accurately distinguish them. Conclusion: Both SEM and XRD can accurately identify gypsum and selenitum and their powders. Traditional identification methods combined with SEM and XRD can provide fast and accurate new methods for the rapid identification and quality control of gypsum and selenitum,their powders.