A novel sensor based on bifunctional monomer molecularly imprinted film at graphene modified glassy carbon electrode for detecting traces of moxifloxacin

Abstract

A novel selective and sensitive electrochemical sensor for moxifloxacin (MFLX) detection based on bifunctional monomer molecularly imprinted polymer (MIP) membranes on a glassy carbon electrode (GCE) modified with graphene was constructed. A suspension of graphene was deposited on the GCE surface. Subsequently, a molecularly imprinted film was prepared by the electropolymerization, via cyclic voltammetry, of o-phenylenediamine and L-lysine as functional monomers in the presence of MFLX as the template molecule. A control electrode (NIP) was also prepared. The electrochemical properties of the MIP and non-molecularly imprinted polymer (NIP) sensors were investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), in which [Fe(CN)₆]^3−/4− was used as an electrochemical active probe. The surface morphology of the imprinted film was characterized by scanning electron microscopy (SEM). The fabrication conditions that affect the performance of the imprinted sensor are discussed. Under the optimal experimental conditions, the imprinted sensor had good linear current responses to moxifloxacin concentrations in the ranges from 1.0 × 10⁻⁹ to 1.0 × 10⁻⁸ M and from 1.0 × 10⁻⁸ to 5.0 × 10⁻⁵ M, with a detection limit of 5.12 × 10⁻¹⁰ M (S/N = 3). The developed sensor was successfully applied to detect moxifloxacin in tablets and human urine samples. Moreover, the fabricated sensor possessed good selectivity and stability, providing a promising tool for immunoassays and clinical applications.