The synthesis and utilization of electrodes modified with conducting polymers is reviewed. Specific issues evaluated include the various approaches available to produce the required functionality at the electrode surface and the practical considerations to be addressed during synthesis, both in terms of hardware requirements and the chemistry of electropolymerization. The review concludes with a survey of the many applications of polymer‐modified electrodes and includes 112 references.
The determination of gold by the application of electrodes modified with anion exchangers is considered. Particular attention is paid to investigating the capability of these electrodes to determine gold(II1) in the presence of copper(I1). Electrodes modified with a film of poly(4-vinyl-pyridine) or either chemisorbed electrochemically generated were investigated. It was found that copper(I1) caused little or no interference in chloride media. However, copper( 11) cyanide complexes interfered with the determination of gold cyanide solutions.
llvTRODUCT1ONThe development of new analytical methods capable of determining trace levels of gold remains an area of interest [l-71. In particular, the development of a method suitable for use in the analysis of refinery plant effluents, to minimize processing losses, or to analyze groundwaters for geological exploration purposes is an attractive proposition.Voltammetric methods, especially anodic stripping voltammetry (ASV), are well suited to the determination of gold. ASV is relatively inexpensive, has adequate sensitivity, and can be operated for on-line analysis [8] or as a portable unit [2]. However, problems arise with the use of ASV for gold analysis in the presence of copper. The tendency of gold and copper to form an amalgam during the electrodeposition step leads to erroneously high analytical results. Therefore, to accurately quantify gold in the presence of copper, it is necessary to perform a chemical separation, usually using solvent extraction, prior to analysis 17, 91. The chemical separation step adds a further degree of complexity to the ASV laboratory method and makes the adoption of the method to on-line or field use more difficult.To solve interference problems such as those described above, various research groups have addressed the development of chemically modified electrodes (CMEs) [ 10-131. Various electrode modifiers have been used to induce nonelectrochemical preconcentration methods prior to voltammetric analysis. For example, electrodes that achieve preconcentration via complex-' To whom correspondence should be addressed. The use of CMEs has also been investigated for the determination of gold [4, 121. Workers in this area were not particularly concerned with overcoming the gold/ copper selectivity problem; however, they did employ electrodes capable of ionexchange preconcentration to enable gold to be determined using an electrochemical reduction process. Both studies employed carbon paste electrodes, into which an anion exchanger could be incorporated.In the course of this work, a CME capable of overcoming the goldkopper selectivity problems was developed. The active component of the electrode is poly(4-vinylpyridine) (PVP), which is known [ 171 to prefer binding anionic gold species over anionic copper species. The use of both chemically and electrochemically generated PW-based polymers was considered. The effect of polymer thickness, the electrochemical stripping waveform, and the presence of copper on the gold response were taken ...
Conductive, electroactive polymers provide a unique platform upon which to construct intelligent materials. These polymers are capable of monitoring and respond ing to the chemical environment in which they are operational. They have properties which simplify the design and development of sensors, based on the principles of molec ular recognition. The conductive nature of the materials enables a range of electrical sig nals to be produced and this inherent electroactivity provides a unique means of triggering chemical responses. This article reviews the accomplishments of various workers in this field to demonstrate that conductive, electroactive polymers provide a basis for intelligent chemical systems.
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