Determination of ascorbic acid using an electrode modified with cysteine self-assembled gold-platinum nanoparticles

We report on a new type of indium tin oxide (ITO) electrode for sensing ascorbic acid (AA). The ITO film was modified with gold-platinum alloy nanoparticles (Au-Pt NPs) functionalized with a self-assembled film of L-cysteine. The Au-Pt NPs were electrodeposited on the ITO film and characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. A cyclic voltammetric study revealed that the electrode exhibits excellent electrocatalytic activity towards the oxidation of AA. The calibration plot for AA is linear over the concentration range from 2 to 400 mu M with a correlation coefficient of 0.9991. The detection limit of AA is 1 mu M.