Part I. Evaluation of silver as a reductive amperometric detector electrode for HPLC and FIA. Part II. Evaluation of supercritical fluid extraction (SFE) as a sample preparation technique. Part III. Development and validation of HPLC methods using supercritical fluid extraction and reversed-phase HPLC with electrochemical detection (LCEC).
Item
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Title
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Part I. Evaluation of silver as a reductive amperometric detector electrode for HPLC and FIA. Part II. Evaluation of supercritical fluid extraction (SFE) as a sample preparation technique. Part III. Development and validation of HPLC methods using supercritical fluid extraction and reversed-phase HPLC with electrochemical detection (LCEC).
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Identifier
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AAI9108172
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identifier
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9108172
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Creator
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Schneiderman, Martin Alan.
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Contributor
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Adviser: David C. Locke
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Date
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1990
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Analytical
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Abstract
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The design, characterization and application of two complimentary analytical tools useful in the analysis of electroactive substances of pharmaceutical, environmental and industrial significance is described. The first, detailed in part I, is concerned with the evaluation of silver as a reductive amperometric detector electrode for HPLC. Three detector variants have been developed, utilizing silver in the form of a continuous silver disc, a segmented silver oxide grid assembly and in a differential arrangement. The dynamic properties of the three cells, i.le., the linear dynamic range, the reproducibility, and dependence on flow rate and electrode area were tested using a series of quinones and nitro-aromatics as model substances. The electrochemical detector (ECD) with the continuous electrode has a wide linear dynamic range, high sensitivity and an extremely rapid response time for analytes reduced at potentials anodic of {dollar}-{dollar}1.2V versus SCE. The analytical superiority and versatility of the silver oxide grid design at potentials cathodic of {dollar}-{dollar}1.2V versus SCE with respect to reproducibility and dynamic range is illustrated through the determination of mercaptobenzotriazole in cooling waters.;Part II is concerned with the use of supercritical fluid extraction (SFE) for sample preparation. A simple laboratory-constructed system is described which allows quantitative and selective recovery of quinones and nitro-aromatics from complex matrices. Parameters such as temperature, pressure, modifier type and amount were optimized for maximum recoveries. Quantitative recovery of various quinones from carbon black samples was maintained down to 1-5 {dollar}\mu{dollar}g/g. The reproducibility and selectivity of the system in the fractionation of samples containing both polar and non-polar polycyclic aromatic hydrocarbons is demonstrated.;In part III, HPLC methods incorporating SFE sample preparation with ECD have been developed for the determination of anthraquinone in wood and paper pulp, nitrosoamines in powdered milk, vitamin K{dollar}\sb1{dollar} in baby formula, retinyl palmitate in ready-to-eat breakfast cereals, menadione in animal feed, Diazepam in tablets, 1-nitropyrene in diesel exhaust, and parathion in oil seeds. The advantages and liabilities of these methods with regard to simplicity, speed, sensitivity, matrix interactions, and selectivity are discussed and are compared to their counterpart compendial methodologies.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
