Studies on Fluorescence Quenching of DBSA-PANI-Employing Nitroaromatics

Owing to their high selectivity and excellent sensitivity, fluorescence-based sensors have continued to receive increasing attention.In particular, fluorescence techniques for sensing explosives, the high energy materials, with the aid of inexpensive and feasible ingredients have become a centre of attraction in recent years. However, the development of such economically viable and reliant materials has remained highly elusive. Herein we report such a novel fluorescent sensor namely, dodecylbenzene-sulfonic acid (DBSA)-doped polyaniline (PANI), which recognizes the presence of nitroaromatic (NAC) explosives, such as 2,4,6-trinitro phenol (picric acid)(PA), 1,3-dinitrobenzene (DNB) and nitrobenzene (NB), in solutions at lower concentrations. This is the first demonstration of its kind where the fluorescent polyaniline is shown to facilitate the detection of NACs by oxidative fluorescence quenching phenomenon. The fluoroscence quenching of DBSA-PANI by NACs has been carried out using N-methyl pyrrolidone and quenching efficiency has been estimated by Stern-Volmer equation. Especially, the DBSA-PANI system turns out to be a promising fluorescent probe for the detection of phenolic nitro-explosive (PA) with high sensitivity and a high Stern Volmer constant. The quenching phenomenon, where DBSA-PANI and NACs interact intensively via intermolecular - interactions, involves a photo induced electron-transfer process that has been evidenced by spectroscopic and redox studies.