Temperature Programmable Injection Techniques for Explosives (Postprint)

摘要

Temperature programmable injection ports promise great versatility, capable of normal split/splitless injections and offering options to inject thermally labile materials with gentle heating profiles. Nitroaromatic and nitramine compounds useful in explosive formulations tend to be thermally labile and limited in volatility. Although LC/MS techniques have been proposed for analysis of these chemicals, GC and GC/MS techniques remain more convenient and more cost effective than LC/MS, and more sensitive than conventional LC analyses for nitroaromatics and nitramine explosives. ECD and other specialized GC detectors have also been described for the detection and analysis of nitroaromatics and nitramines, and these techniques offer additional options for the inexpensive analysis of explosives. All GC based techniques share the common challenges of vaporizing these compounds without excessive losses due to sorption and thermal reactivity. This report will describe results of an investigation to develop GC/MS analyses for nitroaromatics and nitramines, such as TNT and RDX, using a commercially available single-quadrupole GC/MS system with provision for positive and negative ion detection, EI and CI ionization conditions, and a programmable temperature vaporization (PTV) injection port. Conditions investigated include simple split/splitless injections, temperature programmed injections, and injections onto wide-bore pre-columns. GC/MS conditions investigated included electron impact and chemical ionization, using methane as reagent gas. Positive and negative CI conditions were investigated.