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

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)4(2+) 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 cm(2), 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.