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Identification of a new sulfonic acid metabolite of metolachlor in soil

D.S. Aga·E.M. Thurman·M.E. Yockel·L.R. Zimmerman·T.D. Williams
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Abstract

An ethanesulfonic acid metabolite of metolachlor (metolachlor ESA) was identified in soil-sample extracts by negative-ion, fast-atom bombardment mass spectrometry (FAB-MS) and FAB tandem mass spectrometry (FAB-MS/MS). Production fragments from MS/MS analysis of the deprotonated molecular ion of metolachlor ESA in the soil extract can be reconciled with the structure of the synthesized standard. The elemental compositions of the (M - H)- ions of the metolachlor ESA standard and the soil-sample extracts were confirmed by high-resolution mass spectrometry. A dissipation study revealed that metolachlor ESA is formed in soil under field conditions corresponding to a decrease in the concentration of the parent herbicide, metolachlor. The identification of the sulfonated metabolite of metolachlor suggests that the glutathione conjugation pathway is a common detoxification pathway shared by chloroacetanilide herbicides.

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D.S. Aga, E.M. Thurman, M.E. Yockel, L.R. Zimmerman, T.D. Williams. 1996-01-29. Identification of a new sulfonic acid metabolite of metolachlor in soil. https://doi.org/10.1021/es9503600

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