Study on photolytic characteristics of scopoletin in aquatic solutions

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.