Fluorescence Quenching of a Benzimidazolium–based Probe for Selective Detection of Picric Acid in Aqueous Medium

Abstract

A novel fluorescent coumaryl linked benzimidazolium salt has found to be highly selective for nanomolar detection of explosive picric acid, over other aromatic explosives in aqueous medium. The quenching constant and detection limit of the sensor was found to be KSV=1.58 × 104 M−1 and 208 nM respectively for picric acid. UV-Visible studies, time resolved fluorescence results and Density Functional Theory (DFT) calculations inferred the ground-state charge-transfer complex formation as the predominant quenching mechanism for picric acid detection.