AbstractAnalysis of electron-transfer-chemical reaction-electron-transfer (ECE) mechanisms by polarographyandlinearsweepvoltammetryisdiscussed inthecase whom twowell separated successive waves am observed. With polarography it is shown that for moderately fast first-order chemical reactions the limiting current of the second wave is inversely proportional to the square root of the mercury column height . With linear sweep voltammetry the same relation holds between peak current and sweep rate. These relations can be used as diagnostic criteria for ECE mechanisms . Furthermore, a new method using double potential scan is proposed for kinetic analysis of ECE systems . It allows second-order reaction kinetics as well as fast-order ones to be readily determined .
R6alma6-L'analyse des mfcanismes ECE (electrochimique-chimique-electrochimique) par polarographic et par voltam6trie a balayage lin6aire est discut6e dans le cas oil deux vagues bien s6parees sont observ6es. En polarographie, on montre que pour des reactions chimiques du premier ordre moyennement rap ides, le courant-limite eat inversement proportionnel a la racine carrEe de la hauteur de la colonne de mercure . En voltam6trie a variation lin6aire de potential la mยฎme relation lie le courant de plc et Is vitesse de balayage . Ces relations constituent des crit6res de diagnostic des m6canismes ECE. Par ailleurs, une nouvelle m6thode d'analyse cin6tique des m6canismes ECE, utilisant un double balayage, eat proposes . Elle permet d'6tudier simplement Is cin6tique, aussi bien de reactions du second ordre que do reactions du premier ordre .