No abstract

The in situ synthesis is reported of noble metal nanoparticles via 3-glycidoxypropyltrimethoxysilane mediated reduction of 3-aminopropyltrimethoxysilane treated metal salts during sol-gel processing. The method described involves the synthesis of uniform spherical nanoparticles of gold, silver and palladium with controlled size that can be directly utilized for thin film preparation. A detailed study of the synthesis and application of gold nanoparticles to the electrochemical detection of hydrogen peroxide was carried out and reveals that the amplification of hydrogen peroxide sensing is size-dependent. In addition, these nanoparticles exhibit excellent compatibility towards composite preparation. As an example, a nanocomposite with Prussian Blue (PB) is synthesized and found to be useful for the fabrication of chemically modified electrodes (CME). The resulting CME shows dramatic improvement in the electrochemistry of PB with gradual enhancement in electrocatalytic efficiency towards hydrogen peroxide sensing. The nanocomposite is used to study the direct and horseradish peroxidase (HRP)-catalyzed reduction of hydrogen peroxide. The results recorded for hydrogen peroxide analysis show an improvement in sensitivity and limit of detection on decreasing the size of gold nanoparticles in all cases.

The characterization of polyindole made by anodic electropolymerization of indole monomer in dichioromethane is reported based on scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results on SEM show that the granules in the polymer film are arranged in an ordered manner. The domain of the nuclei in the film made under potentiostatic condition is much smaller as compared to the domain of the nucleation in the polymer film made under potentiodynamic condition. The DSC data shows that the polymer is stable at higher temperature. A solid-state potassium ion-selective electrode (1SF) using polyvinyl chloride (PVC) matrix membrane impregnated with valinomycin at the surface of the polyindole-modified electrode is reported. Neutral-carrier impregnated PVC membrane is formed by casting over the surface of the polyindole-modified electrode. The resulting ISE without the incorporation of polyanions in the polyindole film shows high selectivity to K with negligible drift of the baseline potential with a slope of 59 mV/dec within Nernstian behavior. The detection limit of the potassium ion sensor is 6 >( io M with a wide linearity over almost 5 dec. Typical responses of the neutral-carrier impregnated PVC membrane over the polyindole-modified electrode to potassium ion is reported.

No abstract

No abstract