Alain Laudet

Preparation and characterization of graphite-coated metallic electrodes : the graphite-sprayed electrode

Graphite-coated metal electrodes were constructed and evaluated for use in voltammetry. Aluminium, copper and platinum electrodes were sprayed with a colloidal solution of graphite particles dispersed in methyl methacrylate polymer. The polishing step was omitted for anodic stripping voltammetry with a mercury film. The resistance is about 1 Omega. Electrode areas are readily reproduced by utilizing metal supports with equal areas. Background currents are very low and useful potential ranges are extended, with -1.3 to +1.7 V vs. SCE being possible, depending on the electrolyte. It is possible to achieve +/-0.1% precision for the peak-currents in the electrochemical oxidation of ferrocyanide. For phenol, which is strongly adsorbed, a precision of 2.5% can be achieved by polishing the electrode before each determination.

L'electrode a Pate de Carbone Modifiee Son Utilisation en Voltammetrie par Redissolution Anodique a Impulsions Differentielles en Presence d'Un Film de Mercure

Abstract The various problems which are associated with the use of carbon paste electrode as thin mercury film electrode (TKFE) for anodic stripping voltammetry (ASV) can be overcame in a very easy and rapid way. The procedure consists to coat the carbon paste surface by spraying a graphite based conductive solution. For example, the dispersion of colloidal graphite in a mixture of methyl polymethacrylate with butyl acetate (as solvent) gives interesting results. Such a surface is easily renewable and the electrode does not require any pretreatment procedure like cleaning or polarization cycles…, after coating. The technique offers the advantage to limit the risk of sample contamination and memory effects. After pulverisation, a hard, uniform and compact layer is formed after evaporation of the solvent excess. The resulting electrode, electrochemically coated with mercury, exhibits a good stability as shown for the differential pulse anodic stripping voltammetry (DPASV) for cadmium ions. Replicate measure...

The graphite spray electrode and its application in the anodic stripping voltammetry of bismuth

The surface characteristics of carbon-paste electrodes are greatly improved by spraying the surface with graphite from an aerosol. Significant differences are shown by scanning electron microscopy. The available potential range in different electrolytes is narrower but background currents are decreased and reproducibility is improved, compared to the carbon-paste electrode. With a mercury film and 10-min deposition times, the detection limit for bismuth(III) is 2 × 10-9 M by the differential pulse technique.

Voltammetric oxidation of pharmaceutical organic compounds at a new modified electrode: The aluminum graphite spray-covered electrode

Abstract A new graphite spray-modified aluminum electrode has been used to determine clozapine, clothiapine, and loxapine in acetate buffer at pH 4.7 and 20% methanol, down to 5 × 10 −6 M concentrations using differential pulse voltammetry. Reproducibility exceeds that of other solid electrodes, being in the range of 1 to 2%. The electrochemical oxidation products of the latter two compounds are strongly adsorbed, causing diminished electrode response, but response is readily restored by polishing of the sprayed electrode.

A new approach to the use of Auger lineshape effect as a routine technique for characterization of chemical bonding

Abstract A new routine technique for the characterization of the Auger signal shape is proposed. The procedure consists of measuring the Auger signal symmetry with respect to the base line, when recorded in the E [d n ( E )/d E ] derivative mode. The LVV transition of the sulphide ion (S 2− ) in several combinations (Me m S n ) illustrates the analytical possibilities of such an approach.

Construction of an original printed circuit board ion-selective electrode

Abstract A new type of all solid-state electrode with a silver sulphide sensor is described. The electrode is very easy to construct and is relatively inexpensive. Comparaison is made with a similar commercial electrode by direct potentiometry using cysteine solutions.