氰霜唑的光降解研究

The Photolysis of Cyazofamid

采用高效液相色谱法研究了10%氰霜唑悬浮剂在自然光照和黑暗条件下,在水溶液中和黄瓜植株叶片上的消解动态。结果表明,在自然光照下氰霜唑在黄瓜植株叶片上消解的半衰期为63.6h,而黑暗处理下消解不明显。在室内试验条件下,研究了不同pH值、温度、光源和光强等因子对氰霜唑光降解的影响:在pH值分别为4.96、7.02、9.56缓冲溶液中,其半衰期分别为167.7、102.4和64.0min,光解速率随着pH值升高而加快;在pH值为4.96的缓冲溶液中,在15℃、25℃和35℃时,其光解半衰期为368.7、167.7和112.5min。在3700、7600和12300lx的模拟自然光(氙灯)光强下,其半衰期分别为962.7、167.7和120.1min,说明氰霜唑的降解速率与光强和温度呈正相关关系。氰霜唑在pH值为4.96的缓冲溶液在紫外光(254nm)下的半衰期为53.5min。

The photolysis of pesticide cyazofamid was studied under sunlight and darkroom in solvents and on cucumber leaves. The degradation rate was measured through HPLC. The results showed that the half-lives of cyazofamid in sunlight was 63.6 h, and the pesticide was stable in the darkroom. Then the effect of different factors, which included pH, temperature, light resource and the intension of light on the photolysis of cyazofamid were investigated in the lab condition. The results also showed that the half-lives of cyazofamid in buffer solutions with pH 4.96, 7.02, 9.56 were 167.7,102.4 and 64.0 min, respectively. The photolysis rate of cyazofamid increased with the pH values. The half-lives of cyazofamid in the pH 4.96 buffer solutions with 15℃, 25℃ and 35 ℃ were 368.7,167.7 and 112.5 min, respectively. The half-lives of cyazofamid in the pH 5 buffer solutions with 3 700 lx, 7 600 lx and 12 300 lx were 962.7, 167.7 and 120.1 min, respectively. The photolysis ratio of cyazofamid increased with the intention of light and temperature. In addition, the half-lives of cyazofamid was 53.5 min in buffer solution with pH 4.96 under ultraviolet light.