Electrochemical determination of caffeine in coffee and non-alcoholic drinks using g-C3N4-ZnO modified glassy carbon electrode
Toleshi Teshome, Abera Gure, Shimeles Addisu Kitte, Bereket Tesfaye, Guta Gonfa
Abstract
Caffeine is a very important ingredient for preserving the nutritional quality of foods. But, when ingested in excess, it is responsible for numerous health problems, hence the analysis of caffeine in drinks and food products is a pivotal. This study employed g-C3N4/ZnO nanocomposite (NC) to analyze caffeine in coffee and soft drinks. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) were employed for structural characterization. Caffeine oxidation was successfully accomplished by modifying glassy carbon electrodes (GCEs) with g-C3N4/ZnO NC. The sensitivity of caffeine detection using g-C3N4/ZnO/GCE was noticeably improved because of its better electrocatalytic activity. The sensor showed good analytical performances like selectivity, inter-electrode reproducibility, and stability. It also responded a wide range to caffeine concentrations between 1 and 1000 µM. The estimated limit of detection (LOD) and quantification (LOQ) were found to be 0.063 µM and 0.211 µM, respectively. Caffeine content of real samples has also been effectively determined with recovery values of 91.41–103.84 %.