The use of the platinum electrode coated with ultrathin poly(allylamine hydrochloride)/Nafion films for selective detection of hydrogen peroxide

Abstract

In this paper, a novel polyelectrolyte multilayer (PEM) film-coated platinum electrode for the selective detection of H2O2 was presented. The PEM film was formed by the layer-by-layer assembly technique. The quartz crystal microbalance experiments showed that the thickness of the prepared Nafion layer was about 8 nm and depended on the pH of poly(allylamine hydrochloride) solution. The combination of different polyanions and polycations layers was investigated, and it is found that ploy(allylamine hydrochloride) (PAH) and Nafion composited film functioned best as a diffusion barrier toward uric acid (UA) and ascorbic acid (AA) while allowed H2O2 to pass through smoothly. When the platinum electrode coated with two-bilayer film, (PAH/Nafion)2, the amperometric responses of 0.1 mM UA and 0.1 mM AA were respectively 0.008 and 0.006 μA, which were only 0.2% or less of the response of 0.1 mM H2O2 (4.0 μA). The linear response range of the electrode toward H2O2 was from 1.0 μM to 1.0 mM, and the detection limit was 0.3 μM. The electrode also displayed high operational stability and long-term storage stability.