A new strategy for selective detection of nitrated explosives based on a confinement effect of nanocavity

Based on the confinement effect of the CB[8] cavity, a new strategy for explosives detection was developed by using a naphthalene embedded CB[8] complex as receptor. It was found that, dependent on the electronic structures and size of the tested explosives, the trapping of such analytes can significantly influence the photophysical properties of the naphthalene in the CB[8] nanocavity, leading to the direct detection and discrimination of distinctively different groups of trace explosives in the vapor phase, especially including the challenging aliphatic nitro-organics. Control experiments were performed to show the different sensing behaviors between the common organic vapors and nitrate-based explosives, which made it easy to realize the discrimination between target analytes and interferents. Due to the surface attached sensing elements, very fast response and high sensitivity were found in this system. The performed experiments suggested that the naphthalene embedded CB[8]-based sensing protocol opened a new way to develop a new kind of explosive sensor to enable a richer identification of threats.