Supercritical fluid extraction of atrazine and polar metabolites from sediments followed by confirmation with LC-MS

Atrazine is among the most widely used herbicides in intensive agriculture (corn fields). There is thus great incentive to monitor the concentration of this chemical as well as its degradation products, which have to be included in the balance of total toxicity. The metabolic pathway of atrazine in a freshwater sediment has been investigated in this paper. Atrazine was extracted by a supercritical fluid extraction method. 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 metabolites during the extraction. An optimized nondegrading supercritical fluid extraction enabled the reproducible extraction of atrazine and its metabolites from the sediments, showing also that atrazine was metabolized in its hydroxylated analogue, involving chemical abiotic degradation. Our work reports for the first time the use of SFE followed by LC-MS of the polar atrazine metabolites from an environmental matrix.