Small molecule based water-soluble fluorescence material for highly selective and ultra-sensitive detection of TNT: Design and spectrofluorimetric determination in real samples

Abstract

A novel water-soluble double-anthracene bridged material consisting of two cyclotriphosphazene cores (5) as a small molecule was designed and systematically synthesized. The developed small molecule was used for ultrasensitive and highly selective spectrofluorimetric determination of TNT in 100 % aqueous media. The characterization of 5 was examined by standard spectroscopic techniques. Fluorescent sensor features of 5 towards TNT were examined by UV-vis absorption, steady-state-, time-resolved-, and 3D-fluorescence measurements. The interaction and fluorescence mechanisms were investigated by DFT. The designed fluorescent sensor demonstrated a turn-off response towards TNT and required measurement conditions were evaluated for the determination of TNT in environmental waters. The LOD and LOQ for TNT were found as 0.030 and 0.091 mg.L-1 in the linear response of 0.02-15.00 mg.L-1 (R2 = 0.9964), respectively. This study demonstrated that 5 selectively interacted with TNT via intermolecular pi-pi and CH-pi stacking interactions which led to effective electron transfer resulting in a turn-off response. The spectrofluorimetric determination of TNT in environmental waters was performed under optimized conditions and the accuracy was evaluated with HPLC and spike/recovery test. In addition, paper-based test kits were prepared for the detection of TNT, which can be easily used for highly selective, portable, sensitive, and rapid field analysis.