Volume 50, Issue 3 (May 2005)
Differentiation of Composition C-4 Based on the Analysis of the Process Oil
United States military Composition C-4 explosive contains 91% cyclotrimethylene trinitramine (RDX), 5.3% dioctyl sebacate or adipate (DOS or DOA), 2.1% polyisobutylene (PIB), and 1.6% oil. The original military specification required low viscosity engine oil, but this has since been changed to a specially manufactured mineral oil, also called “process oil.” Differentiation of military and commercial Composition C-4 may be possible by analyzing the oil. In this study, samples of Composition C-4 were taken from various lots of U.S. military M112 demolition blocks from two commercially manufactured brands sold in the U.S. The oil and plasticizer were extracted with pentane, and the plasticizer was removed using silica solid phase extraction cartridges. The oil was then analyzed by high-temperature gas chromatography/mass spectrometry (HTGC/MS). Results indicated that HTGC/MS is an excellent discriminating technique for oil comparisons; however, differentiation of Composition C-4 is limited by manufacturer production and distribution practices.