Undoped TiO2 nanoparticles for enzyme free urea detection in milk and neutral electrolyte

Urea serves as valuable biomarker in dairy cow milk to maintain the level of essential contains. However, the increasing urea level in milk has been a concern as it imposes adverse health effects in humans by metabolic misbalance. Therefore, the detection of urea levels in milk is essential to ensure food safety and human health. Development of simple and enzyme free electrochemical sensing platforms has gained attention in recent times. This work introduces anatase TiO2 nanoparticles (NPs) synthesized via a microwave-assisted chemical route as a promising sensing material for electrochemical urea detection. The sensing route offers smaller crystallite size (6.9 nm), uniform morphology enhanced surface area crucial for sensing applications. The carbon Toray paper (CTP) coated TiO2 electrode exhibited effective electrochemical urea detection assessed using cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in a neutral potassium chloride (0.1 M KCl). The sensor demonstrated effective sensitivity of 76.3 µA mM⁻¹ cm⁻² with a limit of detection of 0.93 mM for 1–10 mM linear range of urea concentration. The electrode was then studied for repeatability, reproducibility, and selectivity. Further, the electrode was deployed to detect the urea adulterant in the milk sample, evident by respective CV results, linearity and repeatability. The present work highlights the potential of microwave assisted synthesized TiO2 material as scalable platform for non-enzymatic urea sensing, to safeguard human health by monitoring the urea levels in milk.