Facile Strategy for Preparation of Core/Shell-structured Zinc Oxide-magnetite Hybrids for Quantification of Quercetin and Rutin in Pharmaceutical Herbs

Abstract

In this work, Fe₃O₄@ZnO core/shell magnetic nanoparticles (MNPs) were prepared by a facile method and used as an excellent electrocatalyst to construct an electrochemical sensor for simultaneous determination of quercetin (Qu) and rutin (Ru) in some pharmaceutical herbs including Borage, Chamomile, Asparagus, Teucrium, Tarragon and Pennyroyal. The morphology and structure of the nanoparticles were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. Compared with the bare glassy carbon electrode, Fe₃O₄@ZnO MNPs modified carbon paste/glassy carbon electrode exhibited much higher electrocatalytic activity toward the oxidation of Qu and Ru with increasing of peak currents and decreasing of oxidation overpotentials. Under the optimized condition, the electrochemical parameters such as the effective surface area, charge transfer coefficient, electron transfer rate constant and diffusion coefficient were calculated. A good linearity was obtained in the concentration range of 2.9 × 10^–7–6.47 × 10^–5 M for Qu and 9.9 × 10^–8–9.9 × 10^–5 M for Ru. The limits of detection (S/N = 3) of Qu and Ru were 1.4 × 10^–7 M and 7 × 10^–8 M, respectively. The experimental results demonstrated that the proposed method shows a promising prospect in determination of Qu and Ru in pharmaceutical herbs.