实验室条件下,采用高效液相色谱法研究了东莨菪内酯在水溶液中的光解特性以及初始质量浓度、光源、pH值和温度等因素对其光解的影响。结果表明,东莨菪内酯在水溶液中的光解均符合一级动力学方程。在初始质量浓度为5~40 mg/L范围内,其光解速率随初始质量浓度的增大而降低;在不同光源条件下,其光解速率从大到小依次是:500 W高压汞灯>18 W紫外灯>500 W氙灯;在pH值为5~9的缓冲溶液中,其光解半衰期随pH值的升高而降低,pH为9时的光解半衰期最短,为4.81 h;在5~65℃范围内,其光解速率随温度升高呈先升高后降低趋势,于15℃时达到最大值。研究表明,东莨菪内酯在水溶液中的光解与其初始质量浓度、光源、pH值和温度相关。所得结果可为其环境风险评价提供参考。
The photolytic characteristics of scopoletin in aquatic solutions and its influential factors, including the initial mass concentrations, light sources, pH values and temperatures, were investigated by high performance liquid chromatography( HPLC) in laboratory conditions. The results demonstrated that the photodegradation pathways of scopoletin in water followed the first-order kinetics. The photolytic rate decreased with the increasing initial concentration of scopoletin in pure water at a range from 5 mg/L to 40 mg/L. The photolytic rates of scopoletin under different light sources showed the following sequence:500 W high-pressure mercury lamp〉18 W UV lamp〉500 W xenon lamp. The photolysis half-life of scopoletin decreased with the pH of the buffer solution at a range from 5 up to 9 . The result indicated that the shortest photolysis half-life of scopoletin was 4.81 h in the buffer solution of pH 9 . The trend of photolytic rate of scopoletin at different temperatures from 5℃ to 65℃ was that the rate increased from 5 ℃ to 15 ℃, and reached a maximum at 15 ℃, and then decreased from 15 ℃ to 65 ℃. The results showed that the photolysis rates of scopoletin in aquatic solutions were influenced by the initial mass concentrations, light sources, pH values and temperatures. The results provided a scientific reference for environmental risk assessment of scopoletin.