Degradation Of Trifloxysulfuron Sodium In The Sugarcane Environment And Its Photodissociation In Aqueous Solution

Trifloxysulfuron sodium is an effective, low toxicity, and widely used herbicide. The residue and degradation of trifloxysulfuron sodium were discussed through HPLC method. The photolysis and environmental factors of trifloxysulfuron sodium in aqueous solution were studied. The main results were summarized as follows:1.The HPLC method of residual determination of trifloxysulfuron sodium in sugarcane and soil were established. Sugarcane environmental samples were extracted with methanol and dichloromethane, after concentrate the solution, detected by methanol. the sugar cane leaves must be cleaned up by passing through florisil column. The methods of HPLC analysis were:Agilent-HPLC, with UVD, the chromatographic column was Hypersid-C18 and the stainless steel column was 250mmx4.0mm(i.d), the volume ratio of methanol and phosphoric acid solution was 60:40, the velocity was 0.7mL/min. the temperature was 30℃, the detection wavelength was 250nm and the volume of inject sample was 20μL. the retention time of trifloxysulfuron sodium was 7.67mins and the minimum detectable quantity was 4.00x10-10g. The recoveries and RSD of trifloxysulfuron sodium in sugarcane environment, sugarcane, soil and sugarcane leaves were 81.12%-91.27%,88.10%-99.59%and 83.17%-94.49%. The minimum detectable concentration of trifloxysulfuron sodium in sugarcane, soil and sugarcane leaves were 0.025 mg/kg, 0.0125 mg/kg and 0.025mg/kg, respectively. The extent of accuracy, repeatability and precision met the requirements of pesticide residue analysis.2. The degradation models of trifloxysulfuron sodium in sugarcane leaves and soil in Hunan and Hainan Province were established. The degradation half-lives of trifloxysulfuron sodium in sugarcane soil was 7.19-8.51d, and its half-lives in sugarcane leaves was 3.26-5.25d. Trifloxysulfuron sodium belongs to the kind of pesticide which is easy to degrade. Trifloxysulfuron sodium was safe when applying recommended dose.3. The difference of photodegradation rate of trifloxysulfuron sodium under HPML and sunlight was comparatively distinctive. The order was that HPML (300W) >sunlight. The half-lives were 97.61mins and 24.75 mins, respectively. The half life of the latter is 15.21 times than the former.(1) The effects on the photodegradation of trifloxysulfuron sodium at different values of pH were studied under the HPML. The photolysis rate of trifloxysulfuron sodium under different pH was:pH5>pH7>pH9. It showed that trifloxysulfuron sodium was relatively unstable under acid conditions.(2) The photolytic rate of different concentration of trifloxysulfuron sodium was different under HPML, which means with increase of initial concentration of trifloxysulfuron sodium, the photolytic rate of trifloxysulfuron sodium decreases in water.(3) The photolytic rate of trifloxysulfuron sodium becomes quick as the temperature increases, when the temperature achieves 30℃, the photolytic rate of trifloxysulfuron sodium is the utmost. Continue to increase the temperature, the photolytic rate of trifloxysulfuron sodium was not accelerated.(4) Under the 300W HPML, the photolytic rate of trifloxysulfuron sodium will be accelerated by acetone, and oxidant. And photosensitization of oxidant is stronger than acetone.