Bio-Based Colorimetric Sensors for Detecting Ammonia in the Air

Sustainable ammonia colorimetric sensors made from bio-based compounds prepared from agricultural waste are developed. The sensors operate at room temperature at two important concentration scales: an accident scale
$(> 50$
ppm NH3 in the air) and a health and safety scale (1 ppm – 50 ppm NH3 in the air). The color change of the sensors reacting to ammonia can be followed by the naked eye and quantified with a homemade device and a smartphone. The sensors' response time to high ammonia concentrations (>50 ppm) is minutes, making them useful for safety applications, such as fast detection of ammonia leakages and accidents or alarming high ammonia concentrations at the workplace.