Ultrasensitive and Highly Selective Detection of TNT From Environmental Sample Using Two-Photon Scattering Properties of Aminothiophenol-Modified Gold Nanoparticle

The detection of illegally transported explosives materials has become important for assuring safety at airports and air travel. Trinitrotoluene (TNT) is also one of the most commonly used nitroaromatic explosives for landmines of military and terrorist activities. As a result, there is an urgent need for rapid and reliable methods for the detection of trace amount of TNT for screening in airport, analyzing forensic samples, and environmental analysis. Driven by the need to detect trace amounts of TNT from environmental samples, this paper demonstrates a label-free ultrasensitive and highly selective two-photon scattering (TPS) assay using aminothiophenol-modified gold nanoparticle for TNT recognition in 120 picomolar (pM) level from environmental sample. Our experimental results show that TNT can be detected quickly and accurately in pM level with excellent discrimination against other nitro compounds from environmental sample. A detailed mechanism for significant TPS intensity change has been discussed.