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Peroxynitrite, ONOOÀ also so-called PON, is a very powerful oxidant and cytotoxic agent produced in biological systems by the recombination of nitric oxide and superoxide anion radical. Most of the techniques for assaying PON (chemiluminescence, fluorescence, UV-visible spectroscopy, immunochemistry and EPR ) use indirect methods relying on measurements of secondary species. We report in this study the calibration of a chemically modified Pt ultramicroelectrode by electropolymerized manganese tetraaminophthalocyanine film (MnTAPc) for the determination of PON in aqueous solution. The obtained result allows showing for the first time a real-time calibration curve of the amperometric determination of stable PON in aqueous solution. The sensitivity of the sensor is 14.6 nA mM À1and its detection limit is 5 mM.

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This work presents a methodology for characterizing parallel-plates electrochemical reactors, which allows obtaining precise knowledge about the operation of the unit. Flow distribution is analyzed by injecting a dye at the inlet of the reactor and is followed by a digital video-camera. This has produced knowledge about several parameters such as solution mixing in the diffuser, inter-electrode separation (gap) and linear flow velocity in the reaction chamber of the reactor. Residence time distribution was studied by injecting an electrochemical tracer (Fe(CN) 6 3-

Abstract. In this study, we go into the examination of the possible use of chemically modified electrodes by Hemin embedded in surfactant film of didodecyldimethylammonium bromide or by electropolymerized cobalt porphyrin and Salen films, as potential materials for the effective electrochemical detection of several organic halides (trichloroacetic acid, ethylene dibromide, tetrachloroethylene, trichloroethylene, dichloroacetic acid, 2,4,6-trichlorophenol, 2,4-dichlorophenoxy acetic acid, methoxychloride, etc.), in aqueous and organic solutions. The reported results show an important catalytic effect induced by the modification of the electrode surface by the metal complexes which is materialized by 1.0 V decrease in the reduction potential of the examined organic halide derivatives and a large increase in their reduction current (2 to 500 times). Our descriptive results of the electrocatalytic behaviour of the examined electrodes constitute a first important step in the investigation of the evaluation of a strategy materializing the use of these modified electrodes for the detection of various significant organohalide derivatives.