A nickel hexacyanoferrate and poly(1-naphthol) hybrid film modified electrode used in the selective electroanalysis of dopamine

A mixed-valent nickel hexacyanoferrate and poly(1-naphthol) hybrid (NiHCF–PNH) film was prepared on a gold (Au) electrode by a galvanostatic method, which led to stable and homogeneous hybrid film. The film was characterized using scanning electronic microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. This electrode showed excellent catalytic properties toward dopamine (DA) detection, using cyclic voltammetry and differential pulse voltammetry methods. The electrocatalytic oxidations of DA at different electrodes, such as a bare Au electrode or a poly(1-naphthol)/Au-, or NiHCF–PNH/Au-modified electrode, were investigated in a phosphate buffer solution (pH 7). Interestingly, the NiHCF–PNH-modified electrode facilitated the oxidation of DA, but it did not responded to other electroactive biomolecules, such as ascorbic acid and uric acid. The DA electrochemical sensor exhibited a linear response from 0.1 to 4.3 μM (R2 = 0.9984) and from 4.3 to 9.6 μM (R2 = 0.9969), with a detection limit of 2.1 × 10−8 M, and a short response time (3 s) for DA determination. In addition, the NiHCF–PNH-modified electrode exhibited distinct advantages by its simple preparation, specificity, and stability.