Abstract

The electrocatalytic oxidation of sulfite (SO3 2-) in basic medium (pH = 10.2) at [Ni(II)-5,7,12,14-tetramethyldinaphtho[b,i]-1,4,8, 11-tetraaza[14]annuleneH]++/glassy carbon (mono-[Ni(II)tmdnTAA] ++/GC), and poly-[Ni(II)-5,7,12,14-tetramethyldinaphtho[b,i]-1,4,8, 11-tetraaza[14]annuleneH]++/glassy carbon(poly-[Ni(II)tmdnTAA] ++/GC) modified electrodes was investigated. Both modified electrodes were characterized by cyclic voltammetry. These modified electrodes show an important catalytic effect for sulfite oxidation mediated by the Ni(III)/Ni(II) redox couple. The potential shifted about 570mV in cathodic direction with respect to bare Glassy carbon. The amperometric response (Ipa) for sulfite oxidation at pH = 10.2 in phosphate buffer or a carbonate buffer with both modified electrodes gives a linear correlation between 0.92-1.8mM for mono-[Ni(II)tmdnTAA]++/GC, and 0.25-1.50mM for poly-[Ni(II)tmdnTAA] ++/GC respectively. © 2006 Taylor & Francis.