Bio-based molecules that change colour when they react with ammonia can be used as sensors, reports a Rotterdam-based group in 2023 IEEE Sensors.

Ammonia has applications as a hydrogen carrier, green fuel and reagent. But like many chemicals, you don’t want to inhale it. Especially at concentrations of around 50 ppm, there are health risks that are best avoided, not to mention the potential environmental damage. Jochem Hagenaar, Jan Herselman and colleagues at the Rotterdam University of Applied Sciences have therefore developed a colourimetric sensor that can detect the presence of ammonia in the air.