PH06 Agrochemicals, Pesticides, Pharmaceuticals
Exhibit Hall
8:00 AM - Thursday
(PH042) Determination of diuron and its metabolites in various matrices by solid phase extraction and HPLC-DAD.
Datta, S1, Smith, S1, Kuivila, K2, 1 University of California, Davis, CA2 United States Geological Survey, Sacramento, CA
ABSTRACT- Diuron is a commonly applied phenylurea herbicide used to control broad leaved plants. Herbicides such as diuron can enter wetland ecosystems, and potentially threaten the survival of tidal plants, which act as buffers against tideland erosion. This study examines the bioavailability and biogeochemistry of diuron as an environmental toxicant to plants in estuarine ecosystems. Analytical methods for diuron (N-(3,4-chlorophenyl)-N,N-dimethylurea), and three of its metabolites, N-(3,4-dichlorophenyl)-N,N-dimethylurea (DCPMU), N-3,4-dichlorophenylurea (DCPU), and 3,4-dichloroaniline (DCA) were developed for water, soil, and plant tissue. Solid-phase extraction (SPE) sorbents octadecasilane and a divinylbenzene-N-vinyl pyrollidine copolymer (Oasis HLB,Waters) were evaluated. For soil and sand, sample preparation involved ultrasonication in methanol followed by filtration and SPE. Similarly, plant tissues were blended and extracted with methanol and filtered prior to SPE. Chromatography was achieved on a reverse phase C18 HPLC column using an isocratic mobile phase of acetonitrile/water (55:45) and detection with a diode array detector at 252 nm. Method validation studies to determine detection and quantification limits for each matrix are presented, and application to plant exposure studies is discussed. As part of an integrated study on wetland ecosystem health, the response of Spartina foliosa to diuron exposure was evaluated under laboratory conditions. Plants transplanted from a reference wetland site were grown in a controlled environment and exposed to environmental levels of diuron in a nutrient solution for 4 weeks. Levels of diuron and its metabolites were measured in the nutrient solution, potted sand, and plant tissue, including roots, shoots and leaves.
Key words: metabolites, diuron, hplc, solid phase extraction