Three-dimensional plots from osmium redox-polymer based electrochemical sensors

The electrochemical behaviour of the Os(II)Os(III) redox couple immobilised within the cross-linked [Os(bipy) 2(PVP)10Cl]Cl electrocatalytic redox polymer is purely Nernstian with a slope of 0.058 V decade−1 over the range −2≥log [Os(III)Os(II)]≤+2. This behaviour allows precise instrumental control of the concentration of electrocatalytic sites within the polymer film and hence the catalytic activity of these electrodes. By simple variation of the electrode potential, a series of amperometric responses from conceptually discrete sensory elements was obtained from a small number of electrodes. Using the potential as a variable along with various polymer layer thicknesses, the amperometric responses to a surface reaction (Fe(III) reduction) and a through film reaction (NO2− reduction) at cross-linked [Os(bipy)2(PVP)10Cl]Cl modified electrodes may be isolated individually for quantitative purposes. The results are presented as 3-dimensional plots.