MB-CMC film

Nitrite can also be catalytically reduced by the Mb-CMC film electrode. When an Mb-CMC film electrode was placed in a pH 5.5 buffer containing N02, a new reduction peak appeared at about -0.8 V while the original Mb Fem/Fen peak pair at about -0.25 V was intact. This new peak increased with the concentration of N02 and the catalytic reduction peak of nitrite increased linearly with nitrite concentration in the range of 0.6-8mM with a detection limit of 0.32mM. Oxygen and hydrogen peroxide are also often detected by biosensors based on the direct electrochemistry of Mb in the Mb-CMC film electrode. 

Mb-CMC fihn was made by casting solution of myoglobin and carboxymethyl cellulose (CMC) on pyrolytic graphite electrode. Trichloroacetic acid (TCA), nitrite, oxygen, and hydrogen peroxide can be catalytically reduced at the Mb-CMC film electrode. When TCA was added to a pH 3.0 buffer, an increase in the MbFe reduction peak at about -0.2 V was observed, accompanied by a decrease of the MbFe oxidation peak. The reduction peak current increased as the TCA concentration increased. The catalytic reduction peak current showed a linear relationship with TCA concentration in the range of 7.5 X 10 - 2 X 10 M. Compared with the direct reduction... 

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