Nuclear Magnetic Resonance Signatures of Nitrogen-Containing Compounds.

摘要

Experiments were conducted to determine if unique NMR signatures can be detected and defined for the proton NMR signals of nitrogen-containing compounds. Compounds of particular interest include explosives and explosive stimulants. The effects of off resonance radio frequency (rf) irradiation or pumping in three were observed in three nitrogen-containing compounds: HMT, TNT, and PETN. Similar effects were observed in mannitol and in the plastic explosive C-4 but dielectric heating of the sample C-4 made it impossible to apply the required sequence of rf pulses. The NMR FID signal from C-4 contains two distinct components. At present, methods to enhance the effects of off-resonance irradiation and improve the NMR signature are not obvious. With proper design, it may be possible to take advantage of the observed effects in field-usuable NMR explosive detectors. Keywords: Nuclear magnetic resonance; Free induction decay; Hexamethylenetetramine; Mannitol; Larmor frequency; Trinitrotoluene; Pentaerythritol tetranitrate. (JHD)