SEM and XRD Identification of Mineral Chinese Medicine Alumen, Calcined Alumen, and Their Processed Products / 中国实验方剂学杂志

ABSTRACT

Objective: Ammonium alum is a common counterfeit of Alumen,and the processed product of ammonium alum is a common counterfeits of calcined Alumen. This paper aims to establish a method for identifying Alumen,calcined Alumen,ammonium alum and their processed products. Method: The samples were analyzed by scanning electron microscope (SEM) and X ray diffraction (XRD) in this paper. Result: Ammonium alum and Alumen showed obvious changes in morphology after processing. Both Alumen and ammonium alum showed obvious differences in morphology at×250 and×1 000 times microscope. Alumen presented irregular fragments,clear edge corners,smooth surface,scattered irregular small particles,occasional holes and longitudinal edges. Ammonium alum presented irregular clumps,blunt edges,not obvious edges and corners,uneven surface,scattered smaller and round-like particles. The difference in morphology was not obvious at×250 times microscope between Alumen and ammonium alum processed products. While at×1 000 times,the surface of calcined Alumen was uneven with coarse particles; the surface of counterfeit calcined Alumen was flat,and the coarse particle characteristics were not obvious. XRD can be used to rapidly and accurately identify the primary phase of Alumen,calcined Alumen,ammonium alum and ammonium alum processed productsKAl(SO4)2·12H2O,NH4Al(SO4)2·12H2O,KAl(SO4)2,and NH4Al(SO4)2 respectively, with 2θ angle characteristic value of 23,12,22 and 5 respectively for XRD peak. Conclusion: SEM and XRD techniques can be used for the identification of Alumen,calcined Alumen,ammonium alum and their counterfeit products.