Electrochemical-Sensor Behavior for Determination of Low Urea Concentration using Graphite-TiO2 Composites Immobilized in a Glass Tube

A high urea compound in human blood is indicated for kidney disease, urinary tract stones, and even bladder tumors. It is necessary to take several preventive measures, starting with detecting the urea compound. This study presents the preparation of a working electrode based on graphite-TiO2 (G/TiO2) composites immobilized into a glass tube for sensing urea compound under an electrochemical system. The G/TiO2 composites were successfully synthesized through a physical mixing method and then immobilized into a glass tube for fabricating a working electrode to sense the urea compound under the cyclic voltammetry (CV) technique. The material characterization results show that the nano-TiO2 powder is composed of irregular polycrystalline and amorphous, revealing a broad pattern with low intensity. However, the effect of amorphous materials on the expansion of the nano-sized XRD TiO2 pattern is negligible. In addition, the morphological analysis of graphite has a very tight layer of flakes with a smooth and uniform surface. At the same time, the G/TiO2 composites are also granule-shaped that attached to the graphite surface, identified to cover part of the graphite surface. Under the electrochemical performance test, the excellent composition of TiO2 modifier is 0.5 g mixed into graphite to sense urea compound by using CV technique under a scan rate of 0.5 V.s-1 with 0.1M K3[Fe(CN)6] (+0.1M NaNO3) electrolyte solution. We obtain a standard deviation of 0.361403514 and a detection limit of 0.005976905 mg.L-1 with RSDr and PRSDr values of 5.51% and 3.13%, respectively. The performance of the electrodes over 25 days showed a significant effect on stability over 10 days.