百菌清在甘蓝叶片上的光化学降解

为研究百菌清在甘蓝叶片中的光化学降解，利用高效液相色谱外标法探究了甘蓝叶片的水提取液在氙灯、紫外灯2种光源下对百菌清的光化学降解作用效应；研究了百菌清在花青素含量差异较大的绿甘蓝和紫甘蓝叶片表面的降解行为。结果表明:在氙灯光照下，百菌清在绿、紫甘蓝叶片水提取液中的光降解半衰期分别为80.58 min和70.71 min，降解速率分别是未添加甘蓝叶片水提取液百菌清水溶液的7.17倍和8.71倍；除光催化氧化和光催化还原作用外，百菌清在甘蓝叶片水提取液作用下还可产生光催化水解反应。在紫外灯光照下，百菌清在绿、紫甘蓝叶片表面的降解符合一级动力学规律，光降解半衰期分别为12.68 h和11.25 h；将甘蓝叶片进行创伤处理后，百菌清的光降解速率明显加大。该研究结果可为百菌清在不同蔬菜上的科学使用及其食用安全性风险评价提供参考。

Photodegradation of chlorothalonil on cabbage leaves

In this study, the photolysis of chlorothalonil on cabbage was investigated. The water extracts of the green and purple cabbage were used to investigate the effect of two cabbage leaves on the photolysis of chlorothalonil and the photodegradation of chlorothalonil under artificial light. The results showed that the photodegradation half-lifes of chlorothalonil in aqueous solution were 80.58 min and 70.71 min in the presence of the water extracts of green and purple cabbage leaves under the irradiation of xenon lamp. The degradation rates were increased by 7.17 times and 8.71 times respectively compared to those in the absence of the water extracts of two cabbage leaves. Chlorothalonil underwent photo-oxidation, photoredox, and photocatalytic hydrolysis reactions in the presence of two cabbage leaves water extract. The degradation of chlorothalonil on the leaves of two kinds of cabbages was in accordance with the first-order kinetic with the half-lives of 12.68 h and 11.25 h under UV lamp, respectively. The photolysis rate of chlorothalonil was higher on the traumatic cabbage leaves than that on the untraumatic cabbage leaves. The results could provide reference for the scientific use of chlorothalonil and its food safety risk assessment.