Analytical Sciences

Sensitive and Selective Electrochemical Detection of Carbon Monoxide in Saline at a Pt-Ru/Nafion/MnO₂-Modified Electrode

Hirosato SETO,* Takeshi KONDO,*,** and Makoto YUASA*,**

*Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
**Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan

We fabricated a sensitive and selective electrochemical carbon monoxide (CO) sensor for physiological conditions based on the Pt-Ru system. At a bare Pt-Ru electrode, a linear amperometric response to CO concentration was obtained in the range of 0.9 – 9 μM. However, significant current response to model electroactive interferents for physiological conditions, uric acid (UA), ascorbic acid (AA) and hydrogen peroxide (HP), was also recorded at the Pt-Ru electrode. The response to UA and AA was highly suppressed by coating the Pt-Ru electrode surface with a Nafion layer, and the response to HP was almost completely eliminated by the additional coating with a MnO₂/chitosan layer. Finally, at the Pt-Ru/Nafion/MnO₂ electrode, amperometric CO detection with a sensitivity of 173 nA cm⁻² μM⁻¹ was obtained in the concentration range of 0.9 – 9 μM with the UA, AA and HP signal being below 1.7% at the same concentration of CO.

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