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United States Department of Agriculture

Agricultural Research Service

Title: Persistence of pyrazosulfuron-ethyl and halosulfuron-methyl in aqueous solutions: Comparing hydrolytic dissipation

Authors
item Zheng, Wei - UNIVERSITY OF CALIFORNIA
item Yates, Scott

Submitted to: American Chemical Society National Meeting
Publication Type: Abstract Only
Publication Acceptance Date: September 10, 2006
Publication Date: September 14, 2006
Citation: Zheng, W., Yates, S.R. 2006. Persistence of pyrazosulfuron-ethyl and halosulfuron-methyl in aqueous solutions: Comparing hydrolytic dissipation. American Chemical Society National Meeting. pp# AGRO-121

Technical Abstract: Pyrazosulfuron-ethyl and halosulfuron-methyl are two new highly active sulfonylurea herbicides that have been widely used for weed control in many crops. Chemical hydrolysis is a primary process to determine the environmental fates of this group of pesticides. The hydrolytic dissipation of two herbicides was investigated in different pH aqueous solutions. The hydrolytic rates of both chemicals were pH dependent and accelerated at higher temperature. These results suggest that the pyrazosulfuron-ethyl is much more persistent than halosulfuron-methyl to chemical hydrolysis, although these two herbicides have similar molecular structure. Through identifying individual hydrolytic products of two sulfonylurea herbicides by LC-MS, the acidic and basic-catalyzed hydrolytic mechanisms were proposed, respectively. Additionally, the hydrolysis of two herbicides in the presence of cyclic oligosaccharides (cyclodextrins) was examined in an attempt to evaluate the effect of water-soluble hydroxyl compounds on the environmental fates of sulfonylurea herbicides

Last Modified: 9/21/2014
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