Novel Electrochemical Sensors for Safety and Control in Fermentation Processes

We report on the development of enzyme-free glucose electrochemical sensors for safety and control application in fermentation industry, manufactured by printing Au/TiO2 composites onto gold based planar electrodes. The electrocatalytic materials were prepared in two steps: firstly, colloidal solutions of Au nanoparticles (NPs) ranging from 2 to 40 nm, were synthesized by reduction of an aqueous solution of HAuCl4; secondly, the Au NPs were deposited on the surface of TiO2 by chemical wet impregnation. The use of different reducing agents allowed to control the size of Au NPs, which plays an important role in their electrocatalytic behaviour. Results showed the high electrocatalytic activity of Au NP -modified gold electrodes towards glucose oxidation in alkaline solution; instead no response was given towards ethanol suggesting the possibility to use these kinds of sensors for fermentation process monitoring in industrial technology. The good sensing properties of Au NP-embedded TiO2 composites may be ascribed to the electrocatalytic activity of Au NPs stabilized on TiO2.