PARENT SESSION
PW7 - Biotransformation / Metabolisms / Degradation
Wednesday, 20 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P793) Hydrolysis and Photolysis of Flumioxazin in Aqueous Solutions.

Kwon, Jeong-Wook^*,1, Armbrust, Kevin¹, Grey, Timothy², ¹ Mississippi State Chemical Laboratory, Mississippi State University, PO Box CR, Mississippi State, MS, USA² University of Georgia, Coastal Plain Experiment Station, PO Box 748, Tifton, GA, USA

ABSTRACT- The hydrolysis and photolysis of the herbicide flumioxazin in aqueous buffer solutions (pH 5, 7, and 9) were investigated at 30^oC in the dark and in a growth chamber outfitted with fluorescent lamps simulating the UV output of sunlight, respectively. The rate of hydrolysis of flumioxazin was accelerated by increasing pH and the t_1/2 values at pH 5, 7, and 9 were 16.40, 9.10, and 0.25 h, respectively. Two degradation products were detected. Product I was detected in all buffer solutions while degradation product II was detected in acidic buffer only. Both degradation products appeared to be stable to further hydrolysis. After correcting for the effects of hydrolysis, the photolytic degradation rate also increased as a function of pH and was approximately 10 times higher at pH 7 than that at pH 5, showing t_1/2 values of 4.86 and 41.53 h, respectively. Degradation products formed by photolysis were the same as those formed by hydrolysis.

Key words: hydrolysis, photolysis, flumioxazin, degradation product