Magnetite Nanoparticles Bonded Carbon Quantum Dots Magnetically Confined onto Screen Printed Carbon Electrodes and their Performance as Electrochemical Sensor for NADH

Hybrid magnetite/carbon quantum dots (MagNP/C-dots) were prepared and their characterization performed by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Because of their suitable magnetization and electrochemical properties, they were used as versatile electrode modifiers after magnetically confining onto screen printed carbon electrodes (SPE), with the aid of a miniature external magnet. The reported strategy introduces a convenient procedure for assembling modified electrodes, since the nanoparticles can be easily released by removing the magnet. The non-enzymatic magnetic biosensor showed excellent performance in the determination of NADH at the concentration range 2x10(-7) to 5x10(-6) molL(-1), exhibiting a sensitivity of 0.15 mu molL(-1) and detection limit of 20 nmolL(-1). The MagNP/C-dots/SPE sensor was also successfully applied for the determination of NADH in serum samples. The interference of typical biological molecules has also been investigated. (AU)