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Palladium (Pd) incorporated poly (3,4-ethylenedioxythiophene) (PEDOT) films were synthesized through an electrochemical route and characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrochemical study showed catalytic oxidation of dopamine (DA) with optimum loading of Pd. DA and uric acid (UA) were detected using differential pulse voltammetry (DPV). In the presence of ascorbic acid (AA), DA-AA showed peak potential separation of 0.19 V while 0.32 V between UA-AA on Pd-incorporated PEDOT. These peak separations are large enough for sensing DA and UA in the presence of AA. DA and UA exhibited linear calibration plots and the minimum detection limits are 0.5 and 7 µM respectively. On Pd-PEDOT, the reversibility of DA oxidation was found to increase compared to bare glassy carbon electrode (GCE) and PEDOT modified GCE. Fouling effects were also found to be minimal making Pd-PEDOT composite suitable for electroanalysis.

The behaviour of a poly (aniline boronic acid) (PABA) modified glassy carbon electrode (GCE) for the detection of dopamine (DA) in the presence of excess of ascorbic acid (AA) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques is investigated. On bare GCE, both DA and AA are oxidized at ~0.16 V, whereas on PABA modified GCE they are oxidized at 0.2 and 0.054 V, respectively. Though PABA favours DA oxidation through ester formation with boronic acid motif, the AA oxidation is also promoted by polyaniline backbone through the involvement of AA in the redox of polyaniline. Since both DA and AA undergo oxidation at closely spaced potentials at a PABA electrode, Nafion®-incorporation into the PABA film was examined for selective determination of DA in the presence of AA. The selectivity was due to accumulation of DA on the electrode surface through ester formation with the boronic acid group and suppression of AA oxidative current through charge discrimination by Nafion.

Simultaneous underpotential deposition of lead and thallium from a tartrate medium on a polycrystalline silver electrode is reported. Results of cyclic voltammetric investigations of the effects of concentration and sweep rate on the codeposition behaviour are discussed. Further investigations of the codeposition behaviour through voltammetric experiments using programmed potential inputs are described and discussed in terms of formation of a two-dimensional alloy. Finally, the validity of the existing models of electrochemical phase formation has been investigated under the codeposition conditions.

Results on the simulated η-t transient response of an ‘actively’ corroding system under accelerated Tafel plot (ATP) conditions have revealed the influence of input parameters (Δi, τ) and system parameters (C dl,i corr andb) and explained the observed dependence of kinetic parameters (arrived at on the basis of the intercept-slope method) on τ in certain time domains. New improved methods, which eliminate such dependence and give uniform corrosion rate data over all time domains, are described in the paper.