Highly sensitive amperometric Pt–Nafion gas phase nitric oxide sensor: Performance and application in characterizing nitric oxide-releasing biomaterials

• A sensitive amperometric NO gas sensor based on Pt–Nafion electrodes is reported.
• Selectivity over CO is > 100-fold after conditioning the sensor in 10 ppm CO.
• The sensor can accurately measure NO released from NO-donor doped biomaterials.
• Good correlation is found via measurements using the sensor and chemiluminescence.

A highly sensitive amperometric gas-phase nitric oxide (NO) sensor based on a Pt working electrode chemically deposited on a Nafion film is described. The Pt electrode is chemically deposited on a Nafion 117 membrane by impregnating the film with Pt(NH3)42+ ions, which are then exposed to NaBH4 to precipitate conductive Pt metal. The sensor was characterized with a mass-flow controlled 1 ppm NO standard gas and has an electrochemical surface area of 34 ± 9 cm2, low limits of detection (4.3 ± 1.1 ppb) and a fast response time (<5s) toward changes in gas phase NO levels. Good correlation was found for measurements with the new amperometric Pt–Nafion sensor vs. chemiluminescence results for detecting the rates of NO release from Carbosil2080A polymer films doped with S-nitroso-N-acetylpenicillamine (R = 0.999, m = 0.999, n = 6) and for electrochemical reduction of nitrite to NO (R = 0.999, m = 0.938, n = 3) mediated by a copper(II)-tri(2-pyridylmethyl)amine complex.

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