Nitrite anodic oxidation at Ni(II)/Ni(III)-decorated mesoporous SnO and its analytical applications.

Hydrothermally formed mesoporous SnO was used as a support for nickel chemical deposition and, after subsequent thermal treatment, a high specific surface area (36 m g) Ni/SnO material was obtained. XPS analysis has shown that in the Sn 3d region the spectrum is similar to that of pristine SnO, whereas Ni species are present on the surface as NiO, NiO and Ni(OH). Mixing Ni/SnO with a small amount of Black Pearls (BP) leads to a significant enhancement of the resulting Ni/SnO-BP composite activity for nitrite anodic oxidation, presumably due to the higher surface area (115 m g), to better electrical conductivity and to a certain contribution of the BP to an increase in surface density of the active sites.

Voltammetric determination of N-hydroxysuccinimide at conductive diamond electrodes.

Boron-doped diamond (BDD) electrodes were used to investigate the possibility of detecting N-hydroxysuccinimide (NHS) by linear sweep anodic voltammetry. By increasing the pH the peak potential corresponding to NHS oxidation gradually decreases, suggesting that the electroactive species are the deprotonated ones. An exponential enhancement of the peak current with increasing pH was also observed, indicating that the overall process involves OH--mediated regeneration of these species.

Voltammetric detection of phenol at platinum-polytyramine composite electrodes in acidic media.

A composite obtained by depositing platinum nanoparticles in a polytyramine (PTy) matrix, electrochemically formed on graphite substrate, was used as electrode material for the investigation of phenol oxidation by use of anodic voltammetry. The results show that, in acidic media, the measurement of the oxidation peak current can be used as the basis for a simple, rapid method for the determination of phenol within a concentration range of 0.3-10 mM.

Detection of aniline at boron-doped diamond electrodes with cathodic stripping voltammetry.

Boron-doped diamond (BDD) electrodes were used to investigate the possibility of detecting aniline by linear-sweep cathodic stripping voltammetry. It was found that the dimeric species (p-aminodiphenylamine and benzidine) formed by anodic oxidation of aniline during the accumulation period are involved in electrochemically reversible redox processes and, in acidic media, the shape of the stripping voltammetric response is suitable for aniline detection in the micromolar concentration range. The low background current of conductive diamond is an advantage compared to other electrode materials and allows a detection limit of 1muM.

Potentiometric investigation of the effect of the pH on the ionic transfer of some amino acids at the interface between two immiscible electrolyte solutions.

The effect of the pH on the ionic transfer of glycine and beta-alanine at the interface between two immiscible electrolyte solutions (ITIES) was investigated by a simple potentiometric method. Upon addition of small amounts of solution containing the investigated amino acids, a variation of the potential drop across the interface was recorded, which was found to be pH-dependent. This behavior was explained in terms of a preferential orientation of the amino acid molecules at the ITIES, induced by the different lipoficility of the functional groups.