佐太是一种古老的传统藏药,由水银、硫磺、八金、八矿等原辅料炮制而成,主要用来配制多种珍宝类藏药制剂.佐太作为含重金属藏药的典型代表,安全性与有效性一直备受质疑,而探明佐太的精确理化表征,则是科学阐释该疑问的重要切入点.该研究采用X射线能谱(EDX)、X射线荧光谱(XRF)、同步辐射X射线吸收精细结构(XAFS)、X射线衍射(XRD)、扫描电子显微镜(SEM)、原子力显微镜(AFM),对佐太的元素组成、汞的化学价态与配位结构、物相成分与空间结构、微观形貌进行系统分析.EDX和XRF结果发现,佐太中主要元素为Hg和S,另外还有少量的O,Fe,Al,Cu,K,Ag,Ca,Mg等元素.XAFS分析发现,佐太中Hg是以正二价形式存在,配位数为4,配位原子为S.XRD结果发现,佐太中存在立方晶系β-HgS(空间群为F-43m 216)、斜方晶系单质硫S8(空间群为Fddd 70),以及少量的六方晶系C(空间群为P63/mmc 194)、六方晶系Fe1.05S0.95(空间群为P63/mmc1 94)、六方晶系Cu6S6(空间群为P63/mmc 194)、立方晶系Cu1.8S(空间群为F-43m 216)等;另还发现,佐太的结晶度约为59%,无定型态物质约占41%.SEM和AFM分析发现,佐太应为古代微纳米药物,其微粒多在100～600 nm,并有不少低于100 nm,这些微粒常堆聚成1～20 μm松散的无定型态颗粒.本研究探明了佐太的元素组成、汞的配位信息、物相成分和微观尺寸特征等,对科学解读神秘藏药——佐太的生物效应具有重要的启发。

In order to reveal the chemical substance basis of pharmacodynamic effects of Zuotai,energy dispersive spectrometry of X-ray (EDX),X-ray fluorescence spectroscopy (XRF),synchrotron radiation X-ray absorption fine structure (SR-XAFS),X-ray diffraction (XRD),scanning electron microscope (SEM) and atomic force microscope (AFM) were used to analyze the elements,the chemical valence and local structure of mercury,and the chemical phase composition and micro-morphology of Zuotai.EDX and XRF analysis shows that the main elements in Zuotai are Hg and S,with some other minor elements,such as O,Fe,Al,Cu,K,Ag,Ca,Mg etc.SR-XAFS analysis shows that:the oxidation state of mercury in Zuotai is divalence,its neighbor atoms are S,and its coordination number is four.XRD assay found that β-HgS (cubic,F-43m 216) and S8 (orthorhombic,Fddd 70) are the main phase compositions in Zuotai.Besides,it also has a small amount of C (hexagonal,P63/mmc 194),Fe1.05S0.95 (hexagonal,P63/mmc 194),Cu6S6 (hexagonal,P63/mmc 194),Cu1.8S (cubic,F-43m 216) and so on.And it was found that the crystallinity of Zuotai is about 59%,and the amorphous morphology substance in it is about 41%.SEM and AFM detection suggests that Zuotai is a kind of ancient micro-nano drug,and its particle size is mainly in the range of 100～600 nm,even less than 100 nm,which commonly further aggregate into several to 30 μm loose amorphous particles.In summary,the present study elucidated physicochemical characterization(elements composition,coordination information of mercury,phase composition and micro-morphology) of Zuotai,and it will play a positive role in promoting the interpretation of this mysterious drug.