基于ICP-MS法对桂枝中24种微量元素的测定及形态分析和量变规律研究

目的：通过对广东、广西2个产地多批次、多规格桂枝中Fe、Mg等24种微量元素的测定及形态分析，探索桂枝微量元素的量变规律及形态特征。方法：按照传统煎煮法对桂枝中24种元素进行提取；用0.45 μm微孔滤膜分离提取液中的可溶态与悬浮态微量元素；用LSA-10大孔吸附树脂柱分离可溶态中的有机态与无机态微量元素；并采用正辛醇/水分配体系，在模拟人体胃肠环境条件下，将可溶态中这24种元素分离为醇溶态和水溶态；采用微波消解-电感耦合等离子体质谱法（ICP-MS法）测定桂枝原药、水煎液及水煎液各种形态中24种微量元素的含量；采用SPSS 19.0软件对微量元素进行相关分析。结果：24种微量元素的线性关系系数（r）均大于0.999 0，原药及提取液中元素测定方法的精密度、稳定性和回收率均能满足实验要求，不同产地、不同规格桂枝中部分微量元素含量有显著差异（P<0.05），桂枝中微量元素之间存在显著的或极显著的正相关或负相关（P<0.05）。微量元素的提取率为1.0%~59.4%，可溶态在水中的比率为61.8%~99.1%，悬浮态比率为38.2%~0.9%，微量元素在模拟的人体胃肠环境中的醇溶态溶出率在2%以下，微量元素主要以无机态和水溶态的形式存在。结论：不同微量元素提取率差异显著，可溶态微量元素含量高于悬浮态微量元素的含量，人体胃肠环境醇溶态含量差异不大，小于水溶态的含量，微量元素之间的相关性及形态分析对桂枝临床合理应用具有指导意义。

Objective: To determinate the contents of 24 trace elements including Fe, Mg, etc. in the medicinal plant Ramulus Cinnamomi from different areas (Guangdong and Guangxi)and with different sizes (bran,small twig, middle twig and large twig of Ramulus Cinnamomi), and to discuss the speciation characteristics and content variation of trace elements in Ramulus Cinnamomi. Methods: The 24 elements in Ramulus Cinnamomi were extracted by traditional analytical flowchart program. The species could be divided into suspension species and watersoluble species by 0.45 μm filter and the latter could be further divided into organic species and inorganic species by LSA-10 macroporous resin. These elements in the water-soluble species could be divided into alcohol-soluble and water-soluble species by adopting n-octanol/water system in the simulated conditions of gastric and intestine fluids in the human body. Microwave digestion-inductively coupled plasma mass spectrometry (ICP-MS) was employed for the determination of the contents of trace elements in raw drug,water decoction and various speciations. Correlation analysis method was employed to analyze the characteristics of 24 trace elements in Ramulus Cinnamomi using SPSS 19.0 software. Results: In a certain concentration range,the method validation indicated that the correlative coefficients (r) for all elements were over 0.999 0;the precisions,stability and recovery for all elements in both raw drug and extracts of Ramulus Cinnamomi met the determination requirements. There were significant differences and correlations among the principal components (P<0.05). There were significant or very significant positive or negative correlation among trace elements in Ramulus Cinnamomi (P<0.05). Extractive rates of the elements were in the range of 1.0%-59.4%. The proportion of water-soluble state in aqueous solution was 61.8%-99.1%,and that of the suspension state was 38.2%-0.9%. Alcohol-soluble state proportions for the elements which were found in the gastric and intestine fluids of the human body were less than 2%. Most elements in soluble state were in organic state and water-soluble state. Conclusion: The extraction rates of different trace elements showed significant difference. The soluble trace element content was higher than the content of trace elements in the suspended state. The content of alcohol soluble state in human gastrointestinal environment was not significant,which was less than the content of water soluble state. The results of correlation and speciation analysis can guide us to use Ramulus Cinnamomi accurately.