Attogram Sensing of Trinitrotoluene with a Self-Assembled Molecular Gelator

TLDR

Explosive detection is critical for security, and trinitrotoluene (TNT) is a common explosive that contaminates the environment and threatens human health. The study aims to achieve sub‑femtogram detection of explosives using a molecular sensor. A simple, low‑cost contact‑mode method employs a fluorescent organogelator whose unique molecular packing and photophysical properties enable TNT detection on surfaces or in aqueous solutions. The organogelator in gel form outperforms its solution counterpart, detecting TNT at a record attogram level (~12 ag cm⁻²) with a 0.23 ppq detection limit on disposable paper strips.

Abstract

Detection of explosives is of utmost importance due to the threat to human security as a result of illegal transport and terrorist activities. Trinitrotoluene (TNT) is a widely used explosive in landmines and military operations that contaminates the environment and groundwater, posing a threat to human health. Achieving the detection of explosives at a sub-femtogram level using a molecular sensor is a challenge. Herein we demonstrate that a fluorescent organogelator exhibits superior detection capability for TNT in the gel form when compared to that in the solution state. The gel when coated on disposable paper strips detects TNT at a record attogram (ag, 10–18 g) level (∼12 ag/cm2) with a detection limit of 0.23 ppq. This is a simple and low-cost method for the detection of TNT on surfaces or in aqueous solutions in a contact mode, taking advantage of the unique molecular packing of an organogelator and the associated photophysical properties.