|Lerch, Robert - Bob|
Submitted to: International Congress of Pesticide Chemistry Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 3/4/1998
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Hydroxylated atrazine degradation products (HADPs) are a major class of atrazine metabolites that are persistent in soils and contaminate surface waters throughout the Midwestern United States. Analytical methodology for the recovery of HADPs from soils and sediments has been lacking because their sorption mechanisms were poorly understood. The developed method employs a mixed-mode extractant [3:1 0.5M KH2PO4, pH 7.5:CH3CN (v/v)] designed to disrupt the two primary mechanisms of HADP sorption to soils: cation exchange and hydrophobic interactions. Solid-phase extraction (SPE) is used for sample clean-up and HADP isolation followed by reverse-phase or cation exchange HPLC quantitation using single-stage and tandem mass spectrometry. Detection of these polar metabolites in soil requires the selectivity and sensitivity of new MS or MS/MS techniques because of the complexity of the soil matrix. A Perkin-Elmer Sciex API 365 mass spectrometer is used with an ApCI ionization interface. Concentrations an spectra of HADPs from various field soils with a history of atrazine use will be presented. The daughter ion spectra will enable characterization of the target compounds by their structural information leading to its unambiguous identification. The quantitation and identification of HADPs are important to testing current theories regarding their persistence in surface soils and the geochemical mechanisms responsible for their presence in stream water.