A novel molecularly rabeprazole imprinted electrochemical sensor based on Fe3O4@SiO2–MWNTs nanocomposite

Abstract

A sensitive and selective electrochemical sensor was designed for rabeprazole (RAB) detection using a molecularly imprinting polymer (MIP) modified with Fe3O4@SiO2–MWNTs nanocomposite. Calculation methods were utilized to determine the best monomer and also to check the geometry of the optimized RAB molecule and RAB-PY complex. To obtain the maximum extraction recovery of RAB, the influence of various parameters was investigated and experimental settings were optimized with two multivariable optimization methods of Placket–Burman design (PBD) and central composite design (CCD). Cyclic voltammetry (CV) was used to synthesis the polypyrrole film on a modified pencil graphite electrode (PGE). Analyte extraction from the polymer film and all quantitative measurements were performed by differential pulse voltammetry (DPV). The morphology and characteristics of Fe3O4@SiO2–MWNTs nanocomposite, the modified electrode surface, and also the synthesized sensor surface was investigated with field emission scanning electron microscope (FESEM) coupled to an energy dispersive x-ray (EDX). In optimal conditions, the modified sensor depicted desirable figures of merit of a limit of detection (LOD) of 0.035 μM (S/N = 3), a limit of quantitation (LOQ) of 0.15 μM (S/N = 10), and a linear detection range from 5 to 500 μM. Moreover, the MIP–Fe3O4@SiO2–MWNTs − PGE sensor was showed acceptable repeatability (RSD value of 4.18 %), reproducibility (RSD value of 5.53 %), and stability (reusability) up to one month (92 %). The proposed method was employed for preconcentration and extraction of rabeprazole in pharmaceutical and biological samples, successfully.