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Steady State Reciprocal Derivative Chronopotentiometry with Programmed Currents at Microelectrodes
Author(s) -
Molina Ángela,
González Joaquín,
Morales Isabel
Publication year - 2005
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200403138
Subject(s) - microelectrode , derivative (finance) , chemistry , steady state (chemistry) , reciprocal , transient (computer programming) , aqueous solution , current (fluid) , thermodynamics , electrode , kinetic energy , time derivative , stationary state , analytical chemistry (journal) , chromatography , physics , classical mechanics , linguistics , philosophy , quantum mechanics , computer science , financial economics , economics , operating system
Equations corresponding to the application of Reciprocal Derivative Chronopotentiometry with programmed currents to spherical and disk microelectrodes under steady state conditions have been deduced. Traditional stationary d t/ d E vs. E curves for a current time function of the form I ( t )= I 0 t u , u >0, and the new d I/ d E vs. E curves, which do not depend on the particular characteristics of the applied programmed current I ( t ) are shown for any degree of reversibility of the electrode process. The evolution from transient to steady state for both derivative techniques has been analyzed. Criteria for characterizing reversible and totally irreversible stationary derivative curves, together with easy methods for determining thermodynamic and kinetic parameters of the charge transfer process from the measure of peak parameters are proposed. The validity of the theoretical predictions has been experimentally tested with hexachloroiridate(IV) reversible oxidation and with iron(III) irreversible reduction in aqueous media.