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Analytical Chemistry

2001

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Articles 31 - 33 of 33

Full-Text Articles in Chemistry

Use Of Py-Gc/Ms Analysis Techniques In Animal Waste Management: A Preliminary Survey Of Dairy Manures, Daniel L. Vaughn, Michael A. Kruge Jan 2001

Use Of Py-Gc/Ms Analysis Techniques In Animal Waste Management: A Preliminary Survey Of Dairy Manures, Daniel L. Vaughn, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The increasing practice of industrial-scale agriculture tends to concentrate large masses of animal waste in relatively compact areas, potentially leading to excessive release of polluting nutrients into waterways during major storms. Anaerobic treatment conditions are generally favored to conserve nitrate N as an agricultural commodity. However, overall N contents in waste are often in excess of crop fertilization needs: storing excess N in soluble nitrate form increases pollution potential. Thus the perceived needs of agriculture and society-at-large become at odds. Organic nitrogen forms (e.g., proteins) are more environmentally stable and are less subject to unintentional release. Although U.S. farmers tend …


Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin Jan 2001

Effects Of Humic Acids And Salinity On Pesticide Bioavailability And Toxicity As Estimated By Spme And Toxicity Tests, Laurent C. Mézin

Dissertations, Theses, and Masters Projects

The interactive effects of humic acids (HAs) and salinity on the bioavailability and toxicity of the pesticides chlorpyrifos and 4,4'-dichlorodiphenyltrichloroethane (DDT) were investigated. The effects of various HAs on the toxicity of chlorpyrifos were initially assessed with the chronic MicrotoxRTM test. Environmentally relevant concentrations of Aldrich, Peat, Leonardite and Suwannee River HAs had no significant effect on the toxicity of either chlorpyrifos or copper (Cu), the test's positive control. as reductions in contaminant toxicity had previously been reported for some contaminants by HAs, it appeared that salinity might be a mitigating factor. Thus salinity effects were further investigated with Aldrich …


Development Of Amperometric Enzyme Electrodes For Glucose And Hypoxanthine., Eilish Broderick Jan 2001

Development Of Amperometric Enzyme Electrodes For Glucose And Hypoxanthine., Eilish Broderick

Theses

This thesis is concerned with the immobilisation of enzymes on electrosynthesised poly (o- phenylenediamine) membranes for use on amperometric electrodes. The thesis opens with a discussion of the basic principles of enzymology and a review of a diverse range of biosensors, followed by a consideration of amperometry as governed by the Cottrell equation.

Glucose oxidase and horseradish peroxidase were co-immobilised in poly (o-phenylenediamine) on platinum electrodes at + 0.6 V versus Ag/AgCl. Using this approach the enzymes are entrapped in a strongly adherent, highly reproducible thin membrane, of thickness approximately 10 nm. This one-step procedure produces a glucose sensor with …