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Square‐Wave Voltammetry of Sodium Copper Chlorophyllin on Glassy‐Carbon and Paraffin‐Impregnated Graphite Electrode
Author(s) -
Novak Ivana,
KomorskyLovrić Šebojka
Publication year - 2012
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.201200315
Subject(s) - chlorin , glassy carbon , chemistry , copper , electrochemistry , square wave , cyclic voltammetry , inorganic chemistry , voltammetry , graphite , electrode , adsorption , analytical chemistry (journal) , photochemistry , organic chemistry , porphyrin , physics , voltage , quantum mechanics
Electrochemical oxidation of sodium copper chlorophyllin (CHL) has been investigated at a glassy‐carbon (GC) and paraffin‐impregnated graphite electrode (PIGE) using square‐wave voltammetry (SWV). Square‐wave voltammograms of other two chlorin‐type compounds, namely chlorin e 6 and chlorophyll a , have been studied as well. The measurements were performed in the pH range between 7 and 11. The square‐wave frequency was changed between 8 and 1000 Hz. The oxidation of studied chlorins is a complex, pH‐independent, reversible or quasireversible process, followed by the chemical transformation of the product. The product of the EC reaction of CHL is an electroactive ππ dimer, which strongly adsorbs on the electrode surface and undergoes further oxidation at more positive potential. The electrooxidation of the adsorbed dimer is a pH‐independent irreversible process with the formation of an electroinactive film. The voltammetric behaviour of chlorin e 6 on PIGE was qualitatively similar to that of CHL. The SW voltammograms of chlorin e 6 recorded on GCE and of chlorophyll a recorded on PIGE consisted of only one peak. The SW responses of studied compounds strongly depend on the stabilization of the reaction intermediate by adsorption to the electrode surface.