Explosives Analysis with the 5975-SMB GC-MS with Cold EI

Aviv Amirav, Professor of Chemistry at Tel Aviv University and Director - Aviv Analytical Ltd, December 4, 2013.

Introduction

Effective explosives analysis is very important for homeland security and forensic applications. However, explosives analysis is challenging and the number of explosive compounds that require monitoring is growing with time. Furthermore, the growing use by terrorists of peroxide explosive compounds such TATP (triacetone triperoxide, C9H18O6) and HMTD (Hexamethylene triperoxide diamine, C6H12N2O6) implies that modern analytical techniques of explosive analysis must be as effective with peroxide explosive as with the traditional poly nitro explosives. In fact, there is no limit to the desirable LOD and selectivity of explosives analysis but these features must be combined with an analytical system that enables the analysis of the entire explosives family used by terrorists. We note that the actual system sensitivity and selectivity should be measured by its performance with the most difficult to analyze explosives such as the peroxide explosives and not with TNT and alike. 

Keep reading to find out how the Aviv Analytical 5975-SMB GC-MS with Cold EI uniquely enables the sensitive analysis of the full range of explosive compounds including TATP, HMTD, R-Salt, TNT, ETN, PETN, RDX, Tetril, HMX and Urea Nitrate while providing abundant molecular ions or high mass fragments that improve the detection selectivity and identification capability of these labile compounds.

C-4 Explosives Characterization by the 5975-SMB GC-MS with Cold EI

Aviv Amirav, Professor of Chemistry at Tel Aviv University and Director – Aviv Analytical 

Introduction 

C-4 is a widely used family of plastic explosives. It is composed of explosives, plastic binder, plasticizers and sometimes a marker taggant chemical. The explosive compound in C-4 is RDX, which makes up around 91% of C-4 by mass. The plasticizer is diethylhexyl or dioctyl sebacate and the binder is usually polyisobutylene. Another plasticizer used is dioctyl adipate (DOA). A small amount of SAE 10 non-detergent motor oil is also added. C-4 material is an off-white solid with a texture similar to modeling clay. In view of possible use of C-4 and other related type of plastic explosives (such as PE4 and Semtex) by terrorists there is an important need to have an improved method and instruments for the C-4 source identification. The various C-4 explosives can be correlated to their source in a few ways including: a) Main explosive type such as RDX with or without few percents of co-produced HMX; b) The type of taggant compound added; c) Plasticizer used; d) Oil used and its composition. However, taggant compounds are not always found, particularly in terrorist used C-4, HMX is not always found (co-produced) and while oil characterization is possible, its characterization via isomer abundance analysis although possible with Cold EI it is not sensitive enough in view of the large variety of compounds in the oil and its small concentration. Thus, we selected C-4 characterization via its plasticizers types, their isomer distributions, homologous compounds and major plasticizer related impurities. While for effective C-4 source identification one needs to build a library of C-4 explosives mass chromatograms our goal is to demonstrate the effectiveness of C-4 source characterization method via its plasticizers analysis by the 5975-SMB GC-MS with Cold EI.       

Keep reading to find out how the 5975-SMB GC-MS with Cold EI helps in C-4 source characterization for its identification via the fingerprinting of its plasticizers type, isomers and homologous compounds.

         

Tetryl Analysis using the 5975-SMB GC-MS with Cold EI

Aviv Amirav, Professor of Chemistry at Tel Aviv University and Director - Aviv Analytical Ltd

Introduction

Tetryl, (2,4,6-Trinitrophenylmethylnitramine, C7H5N5O8) is a sensitive explosive compound used to make detonators and explosive booster charges. Tetryl is produced by slowly mixing dimethylaniline with concentrated nitric acid in the presence of sulfuric acid and due to its simple synthesis it is prone for attempted synthesis by terrorists. Tetryl is a thermally labile explosives that is known to be difficult to analyze by GC-MS due to its degradation at the GC injector and at the GC column to N-methylpicramide through a loss of NO and a gain of hydrogen from the column PDMS film. As a result, the analysis of Tetryl is challenging. 

   

We received a sample of Tetryl that was synthesized by A.I. Explosives, Inspection & Services Company (www.aiexplosives.com) that attempted to follow terrorist's synthetic roots and characterize it via the tetryl synthetic impurities.   

In this post we present the uniquely successful analysis of Tetryl perform with Aviv Analytical's 5975-SMB GC-MS.