Improvement of Selectivity and Stability of Amperometric Detection of Hydrogen Peroxide Using Prussian Blue-PAMAM Supramolecular Complex Membrane as a Catalytic Layer

A novel hydrogen peroxide (H2O2) sensor was fabricated by using a submonolayer of 3-mercaptopropionic acid (3-MPA) adsorbed on a polycrystalline gold electrode further reacted with poly(amidoamine) (PAMAM) dendrimer (generation 4.0) to obtain a film on which Prussian Blue (PB) was later coordinated to afford a mixed and stable electrocatalytic layer for H2O2 reduction. On the basis of the electrochemical behaviors, atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), it is suggested that the PB molecules are located within the dendritic structure of the surface attached PAMAM dendrimers. It was found that the PB/PAMAM/3-MPA/Au modified electrode showed an excellent electrocatalytic activity for H2O2 reduction. The effects of applied potential and pH of solution upon the response of the modified electrode were investigated for an optimum analytical performance. Even in the presence of dissolved oxygen, the sensor exhibited highly sensitive and rapid response to H2O2. The steady-state cathodic current responses of the modified electrode obtained at -0.20 V (vs. SCE) in air-saturated 0.1 mol L-1 phosphate buffer solution (PBS, pH 6.50) showed a linear relationship to H2O2 concentration ranging from 1.2 x 10(-6) mol L-1 to 6.5 X 10(-4) mol L-1 with a detection limit of 3.1 x 10(-7) mol L-1. Performance of the electrode was evaluated with respected to possible interferences such as ascorbic acid and uric acid etc. The selectivity, stability, and reproducibility of the modified electrode were satisfactory.