Doped graphene/Cu nanocomposite: A high sensitivity non-enzymatic glucose sensor for food

An amperometric non-enzymatic glucose sensor was developed based on nitrogen-doped graphene with dispersed copper nanoparticles (Cu-NGr). The sensing element was tested in conjunction with a modified glassy carbon electrode for glucose detection. The Cu-NGr composite was prepared by one pot synthesis from a mixture of graphene oxide, copper nitrate and uric acid, followed by thermal annealing at 900 °C for 1 h. Detailed characterizations showed homogeneous copper nanoparticle dispersion and the presence of significant proportion of graphitic nitrogen. The developed electrode presented high electrocatalytic activity towards glucose through synergetic effect of copper nanoparticles and nitrogen-doped graphene. Amperometric analysis confirmed high glucose sensitivity and ultra-low detection of 10 nM glucose over a linear range. The sensor was tested for direct application to detect glucose in food samples for which the sensor displayed high selectivity with excellent reproducibility and recovery in complex food materials.