The emerging potential of green-synthesized nanoparticles as colorimetric sensors for ammonia detection

Ammonia has a wide and diverse application in the fields of agriculture, explosives production, cooling system, antibacterial properties, etc. Despite its beneficial properties, this chemical compound has damaging impacts on human health and the ecosystem. Therefore, its identification and analysis seem necessary for further actions. Among a variety of detection and measurement techniques, colorimetric sensors have advantages such as low power consumption, low limit of detection, portability, on-site monitoring, high accuracy, reasonable price, rapid detection, easy preparation, immunity to electromagnetic interference, etc. This superiority has caused colorimetric sensors to act as good active candidates for the detection of dangerous and toxic substances such as ammonia. The use of nanomaterials in colorimetry has improved the analytic performance of chemical compounds. By employment of the localized surface plasmon resonance (LSPR) properties of metal nanoparticles (MNPs), colorimetric sensors will have the unique ability to detect low concentrations of ammonia. Nanoparticles are synthesized by physical, chemical, and biological (green) methods. Compared to chemical and physical methods, green synthesis has advantages such as being non-toxic, pollution-free, environmentally-friendly, economical, and more sustainable. Therefore, in this narrative paper, we review the colorimetric detection and analysis of ammonia using green synthesized nanoparticles.