基于化学动力学的异绿原酸A在水溶液中的降解规律研究

目的]研究异绿原酸A在水溶液中,于不同pH值、温度、光照、初始药物浓度等条件下的降解动力学特征。方法]采用超高液相色谱(UPLC)法考察不同环境下异绿原酸A含量随时间的变化情况,以化学反应动力学方法计算不同条件下的降解半衰期(t1/2)等反应动力学参数,利用Arrhenius方程计算降解反应的活化能。结果]异绿原酸A在多种条件下的降解均符合一级动力学模型,降解速率呈现pH和温度依赖性;金属离子Fe~(3+)、Fe~(2+)的引入以及紫外光均会使异绿原酸A的降解反应速率加快,而初始药物浓度及氧化的变化对其降解速率影响不明显。在25℃,中性条件下异绿原酸A的降解活化能为96.71 kJ/mol,t_1/2为1 381.9 h。结论]异绿原酸A在酸性,低温环境中较为稳定,高温、强碱、活波金属离子及紫外光均可加速其降解。异绿原酸A在中药材及中成药中广泛存在,此类药物在生产、储存和使用过程中应避免含铁容器,应选择在低温、避光环境下保存。

Study on the degradation of isochlorogenic acid A in aqueous solution based on chemical kinetics

Objective] To investigate the degradation kinetic characteristics of isochlorogenic acid A in aqueous solution under different pH,temperatures,light and initial concentration,etc.Methods] The content of isochlorogenic acid A in aqueous solution was determined by UPLC under different conditions. The half-life period (t_1/2) and other kinetic parameters under different conditions were calculated based on chemical reaction kinetic,and the activation energy of degradation was calculated with Arrhenius equation.Results] The degradation of isochlorogenic acid A followed the first-order kinetics process in different conditions. The degradation rate increases with the increase of pH and temperature. Metal ions Fe³⁺,Fe²⁺ and ultraviolet light could accelerate the degradation rate of isochlorogenic acid A. While the oxidation and initial concentration have no significant effect on the degradation rate. The energy of activation (Ea) was 96.71 kJ/mol and the half-life period(t_1/2) was 1 381.9 h.Conclusion] Isochlorogenic acid A is more stable in acidic and low temperature conditions. The degradation is greatly influenced by the environment of high temperature,strong alkali,active metal ions and ultraviolet light. Isochlorogenic acid A is widely present in Chinese medicinal materials and proprietary Chinese medicines. In the process of extraction and purification,such drugs should avoid the presence of metal ions in containers and water,and should be stored in low temperature and protected from light.