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CAPILLARY ELECTROPHORESIS FOR ENANTIOMER SEPARATION AND MEASUREMENT OF ENANTIOSELECTIVITY OF CHIRAL POLLUTANTS IN THE ENVIRONMENT
Garrison, A W. CAPILLARY ELECTROPHORESIS FOR ENANTIOMER SEPARATION AND MEASUREMENT OF ENANTIOSELECTIVITY OF CHIRAL POLLUTANTS IN THE ENVIRONMENT. Presented at 221st American Chemical Society National Meeting, San Diego, CA, April 1-5, 2001.
Extend existing model technologies to accommodate the full range of transport, fate and food chain contamination pathways, and their biogeographical variants, present in agricultural landscapes and watersheds. Assemble the range of datasets needed to execute risk assessments with appropriate geographic specificity in support of pesticide safety evaluations. Develop software integration technologies, user interfaces, and reporting capabilities for direct application to the EPA risk assessment paradigm in a statistical and probabilistic decision framework.
Chiral pollutants exist as 2 species, -- enantiomers - that have identical physical and chemical properties except when they interact with enzymes or other chiral molecules; then they usually react selectively. This enantioselectivity results in different rates of microbial transformation and differences in toxicity of the 2 enantiomers. To make more accurate risk assessments, it is necessary to understand the relative persistence and effects of the enantiomers; it follows that this understanding depends upon the ability to separate the enantiomers. Enantiomeric separation can be accomplished by the use of chiral columns in GC and BPLC, and by chiral selectors in capillary electrophoresis (CE). This presentation will describe techniques for enantiomer separation by CE, and show applications to environmental problems. For example, we have applied CE with cyclodextrin selectors to the enantiomeric analysis of hundreds of environmental samples spiked with an organophosphorus pesticide (crufomate) and a phenoxyacid herbicide (dichlorprop)to follow the enantioselective microbial transformation kinetics. We have also used CE to follow the enantioselective loss of bromochloroacetic acid spiked into several surface water samples. The advantages and disadvantages of CE for environmental analysis of chiral pollutants will be discussed.
Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LABORATORY
ECOSYSTEMS RESEARCH DIVISION
PROCESSES & MODELING BRANCH