A multiporous electrochemical sensor for epinephrine recognition and detection based on molecularly imprinted polypyrrole

Abstract

A novel multiporous imprinted electrochemical sensor was developed for the recognition and detection of epinephrine (EP) by combining a molecularly imprinted polymers (MIPs) film, silica nanoparticles (SiO₂NPs) and multiwalled carbon nanotubes (MWNTs). A molecular imprinted polypyrrole film was electropolymerized on the surface of a SiO₂NPs and MWNTs modified glassy carbon electrode (GCE) in the presence of EP. With the etching of SiO₂NPs, the obtained sensor exhibited a multiporous network structure to allow for efficient mass transport, which would improve the rebinding rate and increase the efficiency of imprinted sites of the sensor. The multiporous imprinted sensor was characterized using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and amperometric i–t measurement. The influential factors, including the electropolymerization cycles, the scanning rate, the amount of SiO₂NPs, and the incubation time of SiO₂NPs in HF solution were optimized. Under the optimized conditions, the sensor could recognize EP from other structurally similar compounds. A good linearity was obtained in the range of 3.0 × 10⁻⁷–1.0 × 10⁻³ M with a detection limit of 3.0 × 10⁻⁸ M. The MIPs based sensor showed high sensitivity, good selectivity and satisfactory reproducibility for EP determination.