A Reactive Oxygen/ZNitrogen Species Sensor Fabricated from an Electrode Modified with a Polymerized Iron Porphyrin and a Polymer Electrolyte Membrane

We have developed an electrochemical reactive oxygen/nitrogen species sensor that can detect superoxide anion radicals (O 2 ) and nitric oxide (NO). The reactive oxygen/nitrogen species sensor was fabricated by surface modification of an electrode with polymerized iron tetrakis(3-thienyl)porphyrin (FeT3ThP), and it can detect either O 2 - 'or NO by switching the applied potential. Furthermore, we fabricated a sensor with improved selectivity by coating a Nafion® film onto the poly(FeT3ThP)-modified electrode. An interference current caused by NO 2 - was seen for the poly(FeT3ThP)-modified electrode, while the interference current was significantly reduced at the Nafion ® /poly(FeT3ThP)-modified electrode, leading to improved selectivity for NO detection. The current response at the Nafion ® /poly(FeT3ThP)-modified electrode exhibited good linearity in the O 2 - 'and NO concentration ranges 1.3 - 4.1, and 0.5 - 10 μM, respectively. The Nafion®/ poly(FeT3ThP)-modified and poly(FeT3ThP)-modified electrodes are highly versatile, because these electrodes can detect either O2 -' or NO by switching the applied potential. Since the Nafion ® /poly(FeT3ThP)-modified and poly(FeT3ThP)- modified electrodes contain no bio-derived compounds, the reactive oxygen/nitrogen species sensor should be safe even when it is used in vivo.