2.9 Detection of glucose with in-situ pH control Initial scans were conducted with varying concentrations of glucose in PB at pH 7.4 and pH 5.5 using the CA method. Glucose solutions were also prepared at a pH of 6.8, matching the pH of artificial saliva. Glucose solutions at a pH of 5.5 were specifically prepared as the maximum activity of Glucose Oxidase (GOx) is at this pH . Since saliva pH changes with different health status, it was imperative to control the pH both to pH 5.5 to enhance assay robustness and sensitivity as well as facilitating the production of molecular oxygen during the experiments. The generation of molecular oxygen during this process was estimated approximately using Faraday's first law of electrolysis: