Colorimetric detection of ammonia using smartphones based on localized surface plasmon resonance of silver nanoparticles.

In this work, a rapid and straightforward method was developed for colorimetric determination of ammonia using smartphones. The mechanisms is based on the manipulation of the surface plasmon band of silver nanoparticles (AgNPs) via the formation of Ag (NH) complex. This complex decreases the amount of AgNPs in the solution and consequently, the color intensity of the colloidal system decreases.