Pattern recognition based identification of nitrated explosives

Abstract

We report an effective approach for the identification of nitro explosives by the reaction of an electron-acceptor with an electron-donor with and without the addition of g-cyclodextrin (g-CD). A charge-transfer complex was prepared in acetonitrile by the reaction of the nitro explosive TNT as an electron acceptor with the donor N,N,N 0 ,N 0 -tetramethyl-p-phenylenediamine (TMPD). The complex TNT/TMPD converts gradually into TNT À /TMPD + in water with 5% acetonitrile by volume. The inclusion behavior of TNT À /TMPD + with g-CD was studied by UV-visible spectroscopy. The effect of aand b-CD with TNT À /TMPD + was also studied. Similar experiments were also carried out for RDX À /TMPD + with g-CD. The binding of TNT À / TMPD + and RDX À /TMPD + with g-CD were compared for the application of the complexes in a sensor array. Subsequently, the visible absorption spectra of nitro explosives as analytes, such as TNT, RDX, HMX and Tetryl with TMPD in the presence and absence of g-CD, were measured with time. We worked with the same analytes with a second electron donor tetrakis(dimethylamino)ethylene (TDAE) using 96-well plate experiments. Pattern recognition analysis was applied to analyze the data collected and it showed successful discrimination of the nitro explosives. This work represents the simplest colorimetric chemical sensor technique to be used in monitoring the range of common nitro explosives.

Supersensitive Detection of Explosives by Silicon Nanowire Arrays

“…The sensor arrays allow for the detection of TNT vapors directly from samples in air, as no solution is required for sensing. Current experiments are focused on the modification of nano-sensor subgroups in a single array with a broad number of amine derivatives, each with different electron-donating capabilities, as this approach will allow the differentiation between different nitro containing explosives [10] (see Figure 4 S in the Supporting Information for preliminary results). We thus hope, in the near future, to create a universal platform for the label-free simultaneous detection of a larger spectrum of explosive chemical agents, each selectively identified by the specific electrical signal pattern measured by the nano-sensor array.…”

A practical approach to optical cross-reactive sensor arrays

“…PCA is one of the most frequently used methods in pattern recognition in the field of optical array sensors. Not surprisingly, it found application in sensing of a number of analytes including cations, [104][105][106] anions, 102 small molecules such as aminoacids, 107 saccharides, 108,109 explosives, 110 poisonous gases, 111 peptides 112 and proteins, 113,114 sweeteners, 115 beverages, 57,104,116 consumer products such as toothpaste, 102 etc. (Table 1 shows selected examples).…”

Array‐Based Sensors

“…Not surprisingly, it has found application in the sensing of various analytes including cations [70][71][72], anions [73], electroneutral small molecules such as amino acids [74], saccharides [75,76], explosives [77], poisonous gases [78], peptides [79] and proteins [80,81], consumer products including sweeteners [82], beverages [26,70,83], and toothpastes [73], and so on.…”