S. Jaya

Electrochemical phase formation—I. The electrodeposition of copper on glassy carbon

Abstract The electrochemical phase formation of copper on glassy carbon was studied by using linear sweep stripping voltammetry and cyclic voltammetry. The underpotential deposition (UPD) of copper is shown to occur either by nucleation growth processes or adsorption-desorption processes depending on the nature of glassy carbon surface. The bulk deposition processes were found to be independent of the presence or absence of UPD copper on the glassy carbon surface. Similar results were obtained for bulk deposition studies of copper on graphite substrate.

Mono- and multilayer formation studies of silver iodide on silver electrode from iodide-containing solutions

Cyclic voltammetric and single potential step current-time experiments were carried out on the silver electrode in order to understand the nature of kinetic processes involved during the mono- and multilayer formation of silver iodide. Two pre-peaks were noticed at potentials more negative to the multilayer formation and to the Ag/AgI reversible potential. These pre-peaks were found to arise during the monolayer formation of AgI via the adsorption-desorption processes. On the other hand, the multilayer formation of AgI processes occurs by instantaneous nucleation-growth.

Simplified anodic-stripping voltammetric determination of mercury in sea water using a glassy carbon electrode and an acetate-chloride buffer

Various voltammetric techniques developed for the determination of mercury utilise either thiocyanate and/or perchlorate solutions as supporting electrolytes. Utilisation of acetate-chloride medium resulted in a simple, rapid and reliable procedure for the determination of mercury by anodic-stripping voltammetry. The addition of as little as 6 p.p.b. of copper is sufficient to effect the deposition of 1 p.p.b. to 20 p.p.m. of mercury solution without the need for activation during a series of experiments. The procedure developed is suitable for pollution monitoring of mercury in drinking and sea waters.

Anodic-stripping voltammetric determination of arsenic at a copper-coated glassy-carbon electrode

The anodic-stripping voltammetric behaviour of arsenic(III) at a glassy-carbon electrode copper-coated in situ has been investigated. The effects of copper concentration, acidity, deposition potential and sweep rate on the stripping peak have been examined and criteria are given for the choice of experimental conditions. The procedure is applicable to the determination of 7.5-750 ng/ml of arsenic levels and is useful for the analysis of various types of water sample.

Mono- and multilayer formation studies of thallium on glassy carbon electrode

Abstract This paper reports the results of the study of mono- and multilayer formation of cobalt on glassy carbon electrode as a function of sweep rate, cathodic potential limit of the triangular scan and concentration of cobalt. Cyclic and linear potential sweep techniques were employed in carrying out these studies. The multilayer formation of cobalt occurs by 3-D nucleation-growth processes only at concentration ⩾ 10 −3 M of cobalt. On the other hand, the monolayer stripping pattern shows two peaks. The characterization of these peaks by the theoretical models reported in literature revealed that the monolayer formation of cobalt occurs by nucleation-growth and des-ad kinetic processes.

Mono- and multilayer formation studies on silver anodic film formation of silver bromide

The mono- and multilayer formation of silver bromide on silver was investigated by cyclic voltammetric and single potential step current-time transient experiments at different concentrations of bromide. A monolayer peak was noticed at potentials more negative than the Ag/AgBr reversible potential. The electrodeposition of AgBr was shown to occur by adorption-desorption and nucleation-growth kinetic processes during mono- and multilayer formation, respectively.

Galvanic Stripping - A Simple and Versatile Approach to Trace Analysis

Abstract A rapid, simple and versatile analytical technique based on galvanio stripping has been proposed. In this technique, metal ions are preconcentrated onto a mercury film coated glassy carbon electrode (MFGCE). The amal-gamated metals are re-oxidized by galvanic stripping without the aid of any external electrical field or oxidant in solution. The development and relative advantages that can acorue by the utilization of this technique are discussed.

Galvanic stripping determination of trace amounts of lead

A galvanic stripping procedure for rapid determination of trace amounts of lead with a glassy-carbon electrode is described. The method is useful for determining lead at 1-200 ng/ml concentration.

Galvanic stripping determination of sub-microgram amounts of cadmium in high purity zinc materials

A rapid, reliable and precise method for the determination of sub-microgram amounts of cadmium in high purity zinc metal and salt samples by galvanic stripping analysis is described. The procedure involves an initial pre-concentration of cadmium on to a glassy carbon electrode and measurement of the time required for stripping. The stripping is effected through localised galvanic cell formation in the absence of any electrical input such as potential, current or chemical oxidant. The procedure is useful for the determination of 10–104 p.p.b. of cadmium in high-purity zinc materials without any prior separation.

Use of open-circuit pre-concentration of sulphide ion in stripping voltammetry at the parts per billion level of sample

A procedure based on open-circuit pre-concentration using a silver disc electrode was developed. This procedure allows sulphide to be pre-concentrated at concentrations ranging from 0 to 40 p.p.b., with subsequent stripping through a linear cathodic potential sweep. The procedure is precise and reliable, with a similar sensitivity to and a better selectivity than those of conventional cathodic-stripping voltammetry. The procedure is useful for monitoring parts per billion levels of sulphide in tap water samples with a precision of 2%.