An amperometric hypoxanthine biosensor based on Au@FeNPs for determination of hypoxanthine in meat samples.

A xanthine oxidase (XOD) from buttermilk was immobilized covalently onto boronic acid functionalized gold coated iron nanoparticles (Au@FeNPs) electrodeposited on pencil graphite (PG) electrode, via the boroester linkages, between free hydroxyl groups of boronic acid, α-COOH and -NH2 groups of enzyme. The surface functionalization of Fe/Au nanoparticles with boronic acid (Au@FeNPs) on pencil graphite (PG) electrode was characterized by Fourier transform infrared (FTIR), cyclic voltammetry (CV), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Electrochemical impedance spectroscopy (EIS) before and after immobilization of XOD. The biosensor exhibited optimum response within 3s at pH 7.