Portugaliae
Electrochimica Acta

Electrochemistry is on the threshold of a new era of expansion as information from novel spectroelectrochemical techniques is brought to bear on the faradaic processes taking place at electrodes. In this paper, the bases of two important techniques, ellipsometry and in situ FTIR reflectance spectroscopy, are described, and their application to a number of problems is reviewed. The first problem investigated is the adsorption and orientation of molecules on surfaces. Applications of the two techniques to problems of electrochemical promotion and polymer precursors are described. The second problem covered is the mechanism of oxidation of methanol on dispersed platinum catalysts. The evidence will be reviewed for the importance of oxide poisoning in practical systems. Data from FTIR, X-Ray Photoelectron spectroscopy and Moessbauer spectroscopy will then be summarised and the possible mechanisms for ruthenium promotion of platinum discussed in the light of the evidence. Finally, the problem of the growth of electroactive polymers on surfaces, is addressed, taking as example the growth and potential cycling of Prussian Blue films on platinum.

Basic concepts used to express the effects of temperature on the response of ion-selective electrodes (ISEs) are reviewed. A summary of results obtained in a project In progress for studying the Influence of the temperature on the response of ISEs is presented. Data have been obtained both for crystalline membrane electrodes and PYC membrane (mobile carrier) "all-solid-state" electrodes vith supports made of conductive epoxies, as veil as for crystalline membrane commercial electrodes and for PYC membrane electrodes vith internal solution. Special attention has been given to procedures to shift the isopotential point concentration to the operational concentration range of the epoxy based electrodes. It vas found that this can be implemented even for "all-solid-state" crystalline membrane electrodes, by changing the nature of the conductive epoxy used as support for application of the membrane, vhich influences the response characteristics of the electrodes.

Recent advances in the use of solid electrodes in electroanalysis are reviewed and future directions indicated, focussing particularly on hydrodynamic and pulse techniques and new electrode materials.

Copper is an essential element to all living organisms. It takes part in a range of biological processes, from electron transport to oxidation of a range of substrates [1,2], As an essential element and because of the ability to form complexes with organic substances, copper is virtually present in all living tissues [3], Despite its essentiality copper is also toxic . In some cases, the gap between the concentration levels where copper is essential or toxic is very narrow [4], This and the low concentration of copper found in the environment make it necessary to use very sensitive analytical procedures for its determination.

Stainless steel has been commonly used as a biomaterial, particulary for orthopeadic applications. Recent developments; have introduced not only other metallic alloys but also ceramic coated stainless steel to improve wear and corrosion resistance. In this work results are presented on the study of pitting corrosion of A^O^-coated and uncoated stainless steel. A significant decrease in the passivation current, was found for the coated samples