CORE--ANALYTICAL CHEMISTRY CORE

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The aim of the Analytical Chemistry Core is to support Program Project investigators with the development and application of sophisticated methods of chemical isolation, fractionation, structure determination, and quantitative analysis. The function of the Core is to provide cost- efficient means for individual laboratories to obtain access to expertise and capabilities not otherwise available in individual laboratories. The Core will subsidize the use of mass spectrometric, chromatographic, and spectroscopic techniques for the entire program project. Furthermore, the Core will support the development of improved analytical technologies including immunoaffinity isolation, multichannel near-IR fluorescence detectors, laser desorption MS, and atomic force microscopy (AFM). Specific efforts target development of near-IR fluorescence-based ELISAs for determination of biomarkers of exposure including mercapturic acid and other thioether metabolites. UV-visible spectroscopic and mass spectrometric techniques will be used to optimize hapten loadings on antigenic conjugates and enzyme tracers. GC, HPLC, GC/MS, and LC/MS techniques will be employed to confirm immunoassay results and validate assay performance. Synthetic intermediates will be characterized using high resolution MS, MS/MS, and NMR, Uv-vis, and FTIR spectroscopy. Support will be provided for studies of thermal and biological remediation by performing localization and quantitative speciation of organic, organometallic, and inorganic byproducts. Laser desorption mass spectrometry will be employed for rapid speciation of metals (e.g. chromium) and organic contaminants in particulate and solid samples including soils. Atomic absorption spectroscopy, stripping voltammetry, x-ray fluorescence, electron microscopy, and AFM will complement these efforts. Microcolumn HPLC/electrospray MS methods will be to characterize variants of human chorionic gonadotropin as candidate biomarkers of reproductive function, as well as metabolites of naphthalene, nitronaphthalene, and chlorinated ethanes and ethenes. Electrospray MS and laser desorption MS will be employed to characterize adducts of electrophilic metabolites with specific protein targets. Similar methods will be used to probe the structures and expression of key metabolic proteins such as esterases, hydrolases, and glutathione-S-transferase isozymes in target tissues and also in organisms used for bioassays and bioremediation. Bioassay-directed fractionation schemes including column chromatography and ultrafiltration will be developed to explore partitioning of organic and inorganic substances between vapor, particulate, colloidal, and dissolved phases as this partitioning is expected to have profound effects upon transport, bioavailability, and toxicity. The Analytical Core will also provide instruction and training to Superfund researchers in development of sampling protocols, experimental design, instrument operation, and data interpretation, and will act to facilitate collaborations between Superfund projects.