Carbon and nitrogen isotope ratios of factory-produced RDX and HMX | Health & Environmental Research Online (HERO)

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Citation
Tags

HERO ID

2770408

Reference Type

Journal Article

Title

Carbon and nitrogen isotope ratios of factory-produced RDX and HMX

Author(s)

Howa, JD; Lott, MJ; Chesson, LA; Ehleringer, JR

Year

2014

Is Peer Reviewed?

Yes

Journal

Forensic Science International
ISSN: 0379-0738
EISSN: 1872-6283

Publisher

Elsevier Ireland Ltd

Volume

240

Page Numbers

80-87

Language

English

PMID

24814332

DOI

10.1016/j.forsciint.2014.04.013

Web of Science Id

WOS:000340046400016

Abstract

RDX and HMX are explosive compounds commonly used by the military and also occasionally associated with acts of terrorism. The isotopic characterization of an explosive can be a powerful approach to link evidence to an event or an explosives cache. We sampled explosive products and their reactants from commercial RDX manufacturers that used the direct nitration and/or the Bachmann synthesis process, and then analyzed these materials for carbon and nitrogen isotope ratios. For manufacturers using the Bachmann process, RDX (13)C enrichment relative to the hexamine substrate was small (+0.9‰) compared to RDX produced using the direct nitration process (+8.2‰ to +12.0‰). RDX (15)N depletion relative to the nitrogen-containing substrates (-3.6‰) was smaller in the Bachmann process than in the direct nitration process (-12.6‰ to -10.6‰). The sign and scale of these differences agree with theorized mechanisms of mass-dependent fractionation. We also examined the isotopic relationship between RDX and HMX isolated from explosive samples. The δ(13)C and δ(15)N values of RDX generally matched those of the HMX with few exceptions, most notably from a manufacturer known to make RDX using two different synthesis processes. The range in δ(13)C values of RDX in a survey of 100 samples from 12 manufacturers spanned 33‰ while the range spanned by δ(15)N values was 26‰; these ranges were much greater than any previously published observations. Understanding the relationship between products and reactants further explains the observed variation in industrially manufactured RDX and can be used as a diagnostic tool to analyze explosives found at a crime scene.

Keywords

Explosive; Fractionation; HMX; Isotope ratio; RDX; Synthesis