A new compact potentiometric electrode for pH monitoring built upon a glass substrate with a Ce-doped SnO2 layer

Abstract

A novel compact potentiometric electrode specifically designed for pH monitoring, featuring a good construction on a glass substrate coated with a cerium-doped tin oxide (Ce-doped SnO₂) layer. The Ce-doped SnO₂ thin film was created by spray-pyrolysis it on a glass substrate. Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) were used to characterize the deposited metal oxide coating. As a miniature potentiometric electrode, the synthesized Ce-doped SnO₂/glass substrate was utilized to measure a broad pH range (pH 2–12) in aqueous solutions. The electrode had a perfect near-Nernstian response (slope of −58.6 ± 0.7 mV per decade), high potential stability, mechanical durability, and great selectivity towards some common interfering cations and anions. These characteristics made it ideal for quality control and assurance purposes. The electrode's performance parameters and validation measurements were assessed using established procedures. The Ce-doped SnO₂-based electrode satisfactorily monitored the pH of several genuine water, drink, and fruit juice samples, and the data compared well with those obtained using a traditional pH glass electrode. The integration of Ce-doped SnO₂ as the active material marks a significant advancement, providing enhanced electrochemical stability, improved sensitivity, and a wider pH detection range compared to conventional electrodes. The compact design not only reduces the sensor's footprint but also facilitates its application in miniaturized and portable pH monitoring devices, making it highly suitable for advanced analytical and environmental sensing applications.