Factors influencing imazapyr herbicide photolysis in water

We investigated the effect of temperature, formulation, pH and the presence of titanium dioxide on photolysis of imazapyr in water. Irradiation was ca rried out with polychromatic light using Heraeus apparatus equipped with Xe non lamp. The concentration of remaining herbicide was monitored using a hi gh pressure liquid chromatograph (HPLC) equipped with an UV detector at 230 nm. The role of temperature, formulation and pH on the photodegradation of imazapyr was evaluated by the quantum yield determination. Kinetics show a first order dependence of the concentration of imazapyr on time. Temperature and formulation have no effect on photolysis of imazapyr. The decrease of pH in the photolysis medium lowers the rate of photodegrad ation. However, in the presence of titanium dioxide, the degradation of ima zapyr was quick.