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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。
Under laboratory conditions, the photolysis characteristics of scopoletin in aqueous solution and the effects of initial concentration, light source, pH value and temperature on the photolysis were studied by HPLC. The results showed that the photolysis of scopoletin in aqueous solution all accorded with the first-order kinetic equation. Under the condition of different light sources, the photodegradation rate decreased from high to low in the range of initial concentration of 5 ~ 40 mg / L: initial concentration of 500 W high pressure mercury lamp > 18 W UV lamp> 500 W xenon lamp. The half-life of photolysis decreased with the increase of pH value when the pH was 5-9. The half-life of photolysis was 4.81 h at pH 9, In the range of 5 ~ 65 ℃, the photodegradation rate increased first and then decreased with the increase of temperature, reaching the maximum at 15 ℃. Studies have shown that the photolysis of scopoletin in aqueous solution is related to its initial mass concentration, light source, pH and temperature. The results can provide a reference for its environmental risk assessment.