Benzo[ghi]perylene and coronene as ratiometric fluorescence probes for the selective sensing of nitroaromatic explosives.

A simple and efficient fluorometric sensing method is developed for the rapid detection of nitroaromatic explosives, based on the quenching of monomer and excimer emission of benzo[ghi]perylene and coronene. The ratiometric method (I/I) offers a linear response as a function of the concentration of picric acid (PA, i.e. 2,4,6-trinitrophenol), which is used as a model example of the nitroaromatic compounds (NOCs). The detection range is observed to be 0.1-120 μM of PA (22.9 ppb-27.5 ppm). The bright emission of the stable probe excimer and monomer can be easily distinguished under UV lamp from the quenched solution with nitro-aromatic molecules that enables naked-eye detection of nitro-aromatic explosives. The fluorescent paper strips prepared by embedding the probes on the surface of the paper are used for fast, portable and selective detection of NOCs. Our optimized methods can easily detect and quantify NOCs down to 0.1 μM. The sensing process is free of commonly encountered interferences such as volatile organic compounds (VOCs), acids, bases, oxygen, and salt solutions.