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Voltammetric Determination of Both Concentration and Diffusion Coefficient by Combinational Use of Regular and Microelectrodes
Author(s) -
Zhang Hua,
Aoki Koichi,
Chen Jingyuan,
Nishiumi Toyohiko,
Toda Hirokazu,
Torita Eiji
Publication year - 2011
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.200900603
Subject(s) - microelectrode , diffusion , electrochemistry , chemistry , electrode , analytical chemistry (journal) , hemin , redox , limiting current , adsorption , limiting , hydrogen , inorganic chemistry , chromatography , thermodynamics , organic chemistry , mechanical engineering , heme , physics , engineering , enzyme
Two Pt disks with 1.6 and 0.1 mm diameter, whose sizes were accurately evaluated, were applied to voltammetric diffusion‐controlled currents to determine the concentrations of redox species. Since voltammetric peak currents at a regular electrode, I p , and limiting currents at a microelectrode, I L , are proportional to D 1/2 and D , respectively, the ratio I p 2 / I L is independent of the diffusion coefficient but dependents on the concentration. We used this fact to determine the concentrations of ferrocenyl derivatives, hemin, hexacyanoferrate(II), dioxygen gas and hydrogen gas. New insights are not only the absolute determination of concentrations but also the sensitive detection of adsorption of electrochemical products which blocked the voltammetric currents.