Nanostructured Titanium Oxide Platform for Application to Ascorbic Acid Detection

Abstract

Nanostructured TiO2 films have been deposited onto indium tin oxide (ITO) films by sol–gel technique to immobilize ascorbate oxidase (AsOx) onto nanostructured TiO2 films. The TiO2/ITO matrix, AsOx/Nano-TiO2/ITO bioelectrodes have been characterized using spectroscopic techniques and used to fabricate ascorbic acid biosensor. Nanostructured TiO2 based ascorbic acid biosensor has a response time about 20 s, an apparent Km (Kmapp) value of 30.80mg/dL (1.75 mM) and can be used to estimate ascorbic acid concentration up to 200 mg dL−1. The AsOx/Nano-TiO2/ITO bioelectrodes have a detection limit of 50 mg dL−1 with sensitivity of 0.212 mA/mg dL cm2. The enzyme films were found to be thermally stable up to 40 °C and have a shelf-life of about 4 weeks when stored at 4 °C.