An electrochemical sensor for selective detection of dopamine based on nickel tetrasulfonated phthalocyanine functionalized nitrogen-doped graphene nanocomposites

•A N-G/NiTsPc sensor is facilely prepared for the selective detection of dopamine.•N-G provides abundant binding sites for NiTsPc and facilitates the electron transfer.•The nanocomposites have synergic effect for enhancing electrocatalytic efficiency.•The prepared sensor exhibits wide linear range and low detection limit.

A novel electrochemical sensing platform based on nitrogen-doped graphene (N-G)/nickel tetrasulfonated phthalocyanine (NiTsPc) nanocomposites has been developed for selective determination of dopamine (DA). NiTsPc was immobilized on N-G matrix via π-π interaction, while N-G provided a compatible microenvironment for NiTsPc to enhance electron transfer and to retain its electrocatalytic activity as well. The N-G/NiTsPc nanocomposite was characterized by using transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). The proposed modified electrode presented superior catalytic efficiency for DA in the presence of ascorbic acid (AA) and uric acid (UA) owing to the synergistic effect of N-G and NiTsPc. The sensors also exhibited a wide linear range from 1 × 10− 7 to 2 × 10− 4 M and a limit of detection as low as 100 nM with high sensitivity of 88.9 μA mM− 1.

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