Raman microspectroscopy and FTIR crystallization studies of 2,4,6-TNT in soil

Abstract

2,4,6-Trinitrotoluene is a high explosive used in manufacturing landmine, bombs, and other explosive devices. It has been the main source of contamination in groundwater, soil as a result of intentional or accidental releases at many places around the world. Crystallization of TNT in soil from TNT/methanol solutions was carried out and characterized using vibrational spectroscopy. TNT exhibits a series of characteristic bands that allow its detection when in soil. The spectroscopic signatures of neat TNT and TNT in soil samples were determined with Raman Microspectroscopy and Fourier Transform Infrared (FTIR) Microscopy. The spectroscopic signature of neat TNT is dominated by strong bands about 1380 and 2970 cm^-1. The intensity and position of these bands are found remarkably different in soil samples spiked with TNT. The 1380 cm^-1 band is split into a number of bands in that region. The 2970 cm^-1 is reduced in intensity and new bands are observed at about 2880 cm^-1. The results are consistent with a different chemical environment for TNT in soil as compared to neat TNT. Further measurements are required to fully understand the spectroscopic signature of TNT in soil samples. Its detection in soil is essential in landmine detection technology, and could address the improvement of the devices in the mentioned technology.