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ANALYSIS OF CHIRAL PESTICIDES AND POLYCHLORINATED BIPHENYL CONGENERS IN ENVIRONMENTAL SAMPLES
Citation:
Garrison, A W. ANALYSIS OF CHIRAL PESTICIDES AND POLYCHLORINATED BIPHENYL CONGENERS IN ENVIRONMENTAL SAMPLES. R.A. Myers (ed.), Encyclopedia of Analytical Chemistry. John Wiley & Sons, Ltd., Chichester, Uk, , 6147-6158, (2000).
Impact/Purpose:
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.
Description:
Over 25 % of pesticides and other toxic organic pollutants are chiral, as are 19 of the 209 polychlorinated biphenyl (PCB) congeners; that is, they exist as two mirror image species called enantiomers (PCB enantiomers are called atropisomers). The enantiomers of a chiral compound have identical physical and abiotic chemical properties, but usually differ in biological properties such as microbial degradation, uptake and transport across membranes, metabolism rate, and toxicity. Chirality in the environment has become recognized as an important phenomenon since the mid-1980s, and related research has centered on the need to understand the environmental fate and effects of pesticides and PCBS. This article provides a brief back- ground on chiral chemistry in general and the importance of chirality in the drug industry, followed by a summary of examples of the enantioselectivity ofpesticide and PCB occurrencesand degradation in the environmentasgleaned from the scientific literature. The main emphasis is on the analysis of these compounds, with the primary focus on chiral separations. Chiral separations are generally performed by gas chromatography (GC) orhigh-performance liquid chromatography (HPLC) using chiral columns, or, to a lesser extent, by capillary electrophoresis (CE) using cyclodextrin (CD) or other chiral selectors in the run buffer. Summaries of these three separation methods are provided, with figures giving examples of pesticide and PCB enantiomeric separations. Finally, to show the usefulness of these separation methods, applications to several environmental chemistry problems involving chiral pesticides and PCBs are described and illustrated.