Electrochemical Sensing of Ethyl Acetate Volatile Organic Biomarker Using Cobalt Functionalized TiO2 Nanotubes

Food spoilage detection is crucial in preventing foodborne illnesses caused by consumption of spoiled food. The current study explores the potential use of in-situ cobalt functionalized TiO 2 nanotubes (iCo-TNT) in the electrochemical detection of ethyl acetate, a Volatile Organic Biomarker (VOB) released from spoiled tomato. iCo-TNTs were synthesized by electrochemical anodization using titanium sheet as the working electrode and platinum sheet as the counter electrode in an electrolyte of 0.5 wt.% CoF 2 , 0.5 wt.% HF, and 2.5 wt.% H 2 O composition. The anodized tubes were annealed in oxygen flow to ensure the formation of anatase phase. The morphology of iCo-TNT was characterized using SEM and tubes were found to have an inner diameter, wall thickness and length of ~40 nm, ~8 nm and ~1.1 µm respectively. The electrochemical sensing of ethyl acetate was carried out using amperometry in a standard three electrode configuration. Amperometry studies were conducted using iCo-TNT as the working electrode, at a bias voltage of -0.3 V vs an Ag/AgCl reference electrode, with 1mM incremental addition of ethyl acetate VOB in DI water blank solution. The sensor response current was found to be linear and increasing with ethyl acetate addition in the concentration range 0 mM to 4 mM. Furthermore, a mechanism for interaction of ethyl acetate with iCo-TNT was proposed.