[关键词]
[摘要]
目的 研究受热条件下绿原酸的热稳定性、分解动力学和贮存期。方法 利用TG-DTG技术测得绿原酸在氮气气氛中不同升温速率(β)下的热分解曲线,协同使用Achar法、Coats-Redfern法、Kissinger法和Ozawa法等4种方法进行动力学处理,根据热分解的表观活化能(Eα)和指前因子(A)计算推断绿原酸的贮存期。结果 随着升温速率的提高,绿原酸的热分解温度逐渐升高;绿原酸三步热分解的机制依次是三维扩散、二维扩散和化学反应控制,对应的函数名称是Zhuralev-Lesokin-Tempelman方程、Janer方程和反应级数方程;根据第一步热分解的Eα和A推断,在室温(25 ℃)下,绿原酸的贮存期为1.5~2年。结论 4种热分解动力学方法相互验证,获得了绿原酸的热分解动力学方程,由动力学参数求得绿原酸的贮存期,可以为目前大量含绿原酸药品的质量监控提供依据。
[Key word]
[Abstract]
Objective To study the thermal stability, decomposition kinetics, and shelflife of chlorogenic acid under the heat condition. Methods Thermal decomposing curves of chlorogenic acid in different heating speeds were obtained in the nitrogen atmosphere by TG-DTG techniques. Four thermal analysis kinetic methods (Achar, Coats-Redfern, Kissinger, and Ozawa) were used to speculate the probable mechanism of thermal decomposing reaction and the kinetic parameters. The shelflife of chlorogenic acid at room temperature (25 ℃) was calculated by the kinetic parameters of the first stage. Results With the improvement of the heating rate, thermal decomposing tempreture of chlorogenic acid rose. The most probable kinetic mechanisms of the three-stage thermal decomposition were three-dimensional diffusion, two-dimensional diffusion, and chemical reaction, and the corresponding mechanisms followed Zhuralev-Lesokin-Tempelman Equation, Jander Equation, and Reaction Order, respectively. The shelflife of chlorogenic acid at room temperature was about 1.5—2 years. Conclusion With deducing the equation of decomposition kinetics, four thermal analysis kinetic methods verified each other. The shelflife of chlorogenic acid could be used as evaluation method, in order to provide reference for the quality control of the related drug contained chlorogenic acid.
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[基金项目]
国家科技部项目(2009D20110440);湖南省自然科学基金资助项目(10JJ6024);湖南省科技厅项目(2009FJ3045);湖南省高校“林产资源化学与林化产品开发”科技创新团队支持计划(湘教通(2010)212号)