Fluorimetric quantification of picric acid in aqueous medium via smartphone and invisible ink applications using pyrene based sensor

Abstract

• Simple imidazole-pyrene based sensor for quantification of picric acid in aqueous medium. • The fluorescent probe became non-fluorescent in presence of picric acid. • Addition of picric acid caused bare-eye color change from colorless to yellow. • Colorimetric detection of picric acid using smartphone ‘Color detector App’. • Detection of picric acid by the means of invisible ink applications. A simple imidazole-pyrene based sensor (1) has been developed by simple one step reaction and characterized by using common spectroscopic techniques. When various nitroaromatic compounds were incorporated to CH 3 CN:H 2 O (1:2, v/v) solution of 1 , the fluorescent probe turned non-fluorescent in presence of picric acid, upon irradiation at 310 nm. This was accompanied by negligible changes with other molecules along with fluorescent color change from bluish-green to colorless in case of picric acid. Also, the fluorimetric sensing of picric acid was done using smartphone and invisible ink applications. The sensor has been found efficient for the recognition of picric acid in aqueous medium.