Open AccessVisualization of Charge-Transfer Complex for the Detection of 2,4,6-Trinitrotoluene Using Terahertz Chemical Microscope
Author(s) -
Jin Wang,
Hiroki Nagata,
Masaki Ando,
Yuichi Yoshida,
Kenji Sakai,
Toshihiko Kiwa
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac3a2c
Subject(s) - trinitrotoluene , explosive material , terahertz radiation , chemistry , molecule , materials science , analytical chemistry (journal) , nanotechnology , optoelectronics , organic chemistry
This study focuses on the visualization of a charge-transfer complex, namely a Meisenheimer complex, for the detection of uncharged 2,4,6-trinitrotoluene (TNT) explosives by developing a terahertz chemical microscope (TCM) imaging system. The organic amine 3-aminopropyltriethoxysilane (APTES) was immobilized on an SiO 2 -film-coated TCM sensing plate, where it interacted with TNT molecules. The surface electrical potential distribution of TNT, APTES, and the charge-transfer complex was mapped. An electrical potential shift occurred due to the formation of a charge-transfer complex between the electron-rich amino-silane APTES and electron-deficient TNT molecules on the surface of the sensing plate. The electrical imaging and detection of TNT explosives by using the TCM imaging system were demonstrated by measuring the amplitude of the terahertz pulse caused by this electrical potential shift. N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane and N1-(3-trimethoxysilylpropyl)diethylenetriamine were used for further evaluation and comparison of color changes arising from the amine-TNT interactions. The results have shown that TCM imaging is a promising method for the detection of uncharged TNT explosives at a low (sub-parts-per-million) concentration.