SUPERCRITICAL-FLUID EXTRACTION OF ATRAZINE AND POLAR METABOLITES FROMSEDIMENTS FOLLOWED BY CONFIRMATION WITH LC-MS

Atrazine is among the most widely used herbicides in intensive agricul ture (corn fields). There is thus great incentive to monitor the conce ntration of this chemical as well as its degradation products, which h ave to be included in the balance of total toxicity. The metabolic pat hway of atrazine in a freshwater sediment has been investigated in thi s paper. Atrazine was extracted by a supercritical fluid extraction me thod. The first step was to select the most efficient polar modifier: a polar mixture containing a strong nucleophilic agent (MeOH-H2O-Et(3) N) was too reactive, and atrazine was degraded into some of its metabo lites during the extraction. An optimized nondegrading supercritical f luid extraction enabled the reproducible extraction of atrazine and it s metabolites from the sediments, showing also that atrazine was metab olized in its hydroxylated analogue, involving chemical abiotic degrad ation. Our work reports for the first time the use of SFE followed by LC-MS of the polar atrazine metabolites from an environmental matrix.