Highly Sensitive Electrochemical Glutamate Microsensors for Food Analysis ^†

Electrochemical microsensors are ideal to measure substances with low concentration in complex environments. The primary excitatory neurotransmitter l-glutamate is present in many foods as a distinctive flavour (enhancer) with a wide concentration range. In comparison to other methods, electrochemical sensors allow the rapid, precise, cost-effective, online measurement without any sample treatment. We developed a disposable electrochemical microsensor platform with multiple integrated, highly sensitive (detection limit <150 nM) and selective enzyme-based glutamate biosensors. We showed both the precise determination of glutamate levels in processed foods with high glutamate content (15–40 mM), e.g., broth, and in foods with low natural concentrations such as different types of cow’s milk (~250 μM). Hereby, we successfully demonstrated the capabilities of electrochemical biosensors in food monitoring, analysis and quality control.