Amperometric Nitric Oxide Sensor Based on Nanoporous Platinum Phthalocyanine Modified Electrodes

Abstract

This article describes the fabrication of electropolymerized Metallo 4', 4″, 4‴, 4'''' tetra-amine phthalocyanine (poly-MTAPc) modified electrodes for the detection of nitric oxide (NO) in phosphate-buffered saline (PBS) at pH 7.4. A two-step synthetic protocol using a laboratory microwave reactor was adopted to provide three MTAPc complexes bearing different metal centers (M = Cu(2+): CuTAPc, M = Zn(2+): ZnTAPc, and M = Pt(2+): PtTAPc). The MTAPc complexes and the intermediates were characterized by MALDI-TOF mass spectrometry, UV-vis spectroscopy, (1)H NMR spectroscopy, and elemental analysis. The MTAPc products were separately electropolymerized either onto a glassy carbon (GC) electrode as a thin-film or within the pores of Anodisc nanoporous alumina membrane as a densely packed array of poly-MTAPc nanotubes to produce two electrode systems. In the latter system, the surface area enhancement provided by the nanotube-arrayed morphology of the poly-MTAPc enabled a high faradaic (signal) to capacitative (background) current during NO electro-oxidation. Amperometric detection of NO using these two electrode systems shows that the sensitivity and linear ranges were insensitive to the metal centers (M = Cu(2+), Zn(2+), and Pt(2+)) of the poly-MTAPc material.