Application of pressurized fluid extraction for quantification of propellant components

摘要

Analysis of explosives, mainly smokeless powders and explosives mixtures, is an integral part of the production of explosives, fulminating compounds or propellants. Nowadays, chromatographic methods are used for these analyses, for example high performance liquid chromatography with ultraviolet detection (HPLC/UV). Modern methods and classical methods of propellant analysis (titration, gravimetry) require sample preparation to analysis. It means that target analytes have to be isolated from sample for their analysis. Isolation step of propellant analysis includes extraction methods usually. The extraction method is always selected according to the matrix of a sample and kind of a sample. Conventional method for preparation of propellant samples and explosives samples is Soxhlet extraction with dichloromethane or diethyl ether as extraction agent. Substitution of Soxhlet extraction and development of new chromatographic method for analyzing of propellant components were major goals of our work. Pressurized fluid extraction (PFE) is modern and efficient extraction method. The same efficiency or higher extraction efficiency using PFE was observed than using Soxhlet extraction (SE). Time of extraction was shorter using PFE than using Soxhlet extraction (8 hours). Combination of gas chromatography and mass spectrometry (GC/MS) is faster, more sensitive and more accurate method for analyses of propellant components than conventional HPLC/UV. First of all, advantage of GC/MS method is detection of newly tested propellant components, because some of them do not provide of response using ultraviolet detector (for example acetyl tributhyl citrate - gelifying agent in propellants). Secondly, substances can be immediately identified by comparing measured MS spectra with library spectra. Therefore, the GC/MS method fulfills also the qualitative part of smokeless powder analysis (especially the unknown ones).