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A differential pulse anodic stripping voltammetric procedure was developed for the determination of trace amounts of iron(II) in the presence of iron(III) at a carbon paste electrode (CPE) modified with dithiodianiline and gold nanoparticle. At the pH working of 3.0, a wide concentration range from 0.1 nM to 100 nM was observed with the detection limit of 0.05 nM. The relative standard deviation for a solution containing 50 nM of iron(II) was found to be 3.11 % (n=9). Possible interferences from the coexisting ions were also investigated. The validity of the method and applicability of the sensor were successfully tested by determining of iron(II) in lentil, wheat seed and barley seed samples.

Novel conducting copolymers of N-methylaniline (NMAn) and o-aminophenol (o-APh) were synthesized electrochemically with different feed ratios of the monomers in sulfuric acid solution. The obtained homopolymers and copolymers were characterized with cyclic voltammetry, scanning electron microscopy (SEM), in situ conductivity measurements, in situ UV-Vis., and FT-IR spectroscopy techniques. The influence of applied copolymerization potentials and monomer feed ratio on the optical properties and conductivity of the copolymers were discussed. The in situ UV-Vis. spectroscopy results revealed strong absorption bands at different applied electrode potentials. The conductivity of copolymers increased with increasing the o-APh concentration in feed ratios. The fundamental differences between the structures and morphology of the homo- and copolymers were observed from FT-IR spectroscopy and SEM analysis.

This study represented a novel conducting poly (p-nitroaniline-co-p-aminophenol) (P(p-NAn-co-p-APh)) material, obtained by electrocopolymerization of para-nitroaniline (p-NAn) and para-aminophenol (p-APh) in aqueous sulfuric acid solution. Copolymerization was carried out using cyclic voltammetry technique on gold electrode with different monomer feed concentrations. The obtained polymer and copolymer films had been characterized by scanning electron microscopy (SEM), in situ conductivity measurements, in situ UV-Vis, and FT-IR spectroscopy. Initial cyclic voltammograms of p-NAn, p-APh and p-NAn + p-APh showed that the peak potentials were located at different values. The in situ conductivity of the copolymers measured between −0.20 V< ESCE< 0.70 V increased with decreasing the [p-NAn]/[p-APh] concentration ratio. In situ UV-Vis. spectra of the obtained samples revealed strong absorption bands at different applied potentials and wavelengths. The structure and morphology characterizations of homo and copolymer films were studied by FT-IR spectroscopy and SEM analysis. Fundamental differences between the morphology of the homo- and copolymers were observed. The mechanism of the electrochemical copolymerization reaction was discussed as well.