Smart Nitrite Sensor for Real Time Food and Water Quality Monitoring ‒ Improving Public Health

Abstract

In the preparation of CCE, SiO2 has been used as the support, due to its characteristics in forming very stable and mechanically resistant framework, resulting a porous structure of the support, a desirable characteristic in term of immobilization of electroactive species with good yield of surface density, silica has been the main component of the ceramic material. However, it is known that modification of the surface requires the presence of more active and reactive functional groups. On silica surface the reactive species are the silanol, Si-OH, groups. In this project the main objective is to study the synthesis, characterization and application of a new carbon ceramic, designated as SiO2/Al2O3/C (C= graphite). The technique of the conducting ceramic material was the sol-gel processing technique. The well characterized SiO2/Al2O3/C, modified with 3-n propylpyridinium silsesquioxane chloride functional groups, and tested as an electrochemical sensor of NO2- in the environment. Nitrite plays an important role in environmental and biological processes, its monitoring is important since it is used as a food preservative against antimicrobial action. However, the presence of nitrite in food or drinking water can be hazardous to health, especially for infants and pregnant women, and, in the stomach, it can react with dietary components to form toxic and carcinogenic nitrosamines. The presence of nitrite in environmental samples, arising from industrial activities, indicates the extend of pollution and eutrophication of natural waters. So in this project, a novel nitrite sensor fabricated based on a SiO2/Al2O3/C/SiPy+Cl new conducting ceramic material. The degree of functionalization of the material determined by C, H, N elemental analysis and the local structure by 13C and 27Si SEM and diffuses reflectance Raman spectroscopies.