目的 通过研究金礞石炮制前后阳离子交换容量（CEC）及交换性阳离子量的变化，揭示其与金礞石结构变化的关系，为探究金礞石的炮制作用提供科学依据。方法 对金礞石及其煅品进行阳离子交换试验，测定其CEC，并以ICP-AES测定交换后溶液中各主要元素的量，比较炮制前后CEC及各元素交换量的变化。结果 金礞石炮制后CEC显著下降，蛭石层间各可交换性阳离子交换量降低，四面体及八面体阳离子交换量增加，金礞石炮制后交换性阳离子的组成显得更为均衡，且不同产地及来源的样品间差异显著减小。结论 金礞石炮制后层间自由水及部分结合水的脱失使得层间可交换性阳离子与结构层作用力增强，可交换性降低；部分结构羟基的脱失破坏了相应的八面体结构，其中的八面体阳离子因而具有可交换性；金礞石炮制后结构边缘及缺陷位置增多，在交换液的作用下易破键水解释放出大量的四面体及八面体阳离子。炮制对于缓和金礞石药性，提高金礞石药材整体质量，缩小产地差异对其药效的影响，增加用药的安全性、有效性具有重要意义。

Objective To research the changes of cation exchange capacity (CEC) and the amount of exchangeable cation (AEC) of Micae Lapis Aureus (MLA) before and after processing, and to observe the relationship between CEC changes and structure changes, which could provide the reference for MLA processing. Methods Cation exchanging test was used to determine the CEC and ICP-AES to observe the content of main elements after exchanging. CEC and AEC in MLA before and after processing were compared. Results The CEC reduced obviously and the AEC also decreased. The AEC of tetrahedron and octahedron increased. The composition of exchangeable cations was well-distributed after MLA processing and the differences among samples from different habitats decreased significantly. Conclusion The deletion of interlaminar free water and bound water after MLA processing could make the interaction between interlaminar exchangeable cations and structural layer increased, but the exchangeability reduced. The deletion of some structural hydroxyls could destroy the structure of corresponding octahedron thus causing cations exchangeable. The increases of the structure edges and the defective locations are benificial to break the bond and promote the hydrolysis so as to release the tetrahedron and octahedron cations under the action of the exchanged fluids. In general, the processing could ease the property of MLA, improve its quality, decrease the effects of habitat difference on pharmacological efficacy, and increase safety and effectiveness.

“十一五”国家支撑计划重点项目——我国当前急需建立和提高的药品监督检验技术研究（2008BAI55B00）