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A fully computer controlled apparatus for interfacial tension measurements at the mercury/solution or solution/solution interface is described. The apparatus is based on the drop-shape technique and employs a solid state video camera to take the drop profile; measurements can be accomplished as a function of interface polarization potential, temperature and solution concentration. Overall data reproducibility is better than 0.06%, with an acquisition time of about 45 s for each experimental data point.

An iridium-iridium oxide electrode for in vivo monitoring of blood pH changes is described. Because of its small size, sensitivity, flexibility, strength and fast response, this electrode is suitable for acute implantation even in the small vessels of animals such as rats or guinea pigs, allowing continuous pH monitoring anywhere in the central arteries or veins. Excellent noise-free records have been obtained in the in vivo experiments in animals.

The adsorption of the nonanoic acid at the electrified Hghqueous solution interface is studied by means of capacity and surface tension measurements. Comparison of the experimental r,,, value with the calculated more favoured solvated conformation suggests that the acid is adsorbed in a partially coiled conformation. The adsorption free energy here determined, together with previously reported values found in the literature concerning other saturated acids and alcohols, is compared with reactivity and calculated molecular descriptors. The collected evidence suggests that the hydrophobic nature of the acid is responsible for the adsorption, while the electric field/molecule interaction, occurring at the electrified interface, governs the desorption. Lastly, some experimental (capacitive transients, effect of the temperature on the tensammetric curves) and theoretical findings are discussed which indicate that the adsorbed acid monolayer should be regarded as a usual, in the field of adsorption at electrodes, disordered network. Thus excluding the occurrence of a two-dimensional phase transition involving the formation of a 2 D solid-like film.