Chemical attribution of the home-made explosive ETN – Part II: Isotope ratio mass spectrometry analysis of ETN and its precursors
article
In this follow-up study the collaboration between two research groups from the USA and the Netherlands was continued to expand the framework of chemical attribution for the homemade explosive erythritol tetranitrate (ETN). Isotope ratio mass spectrometry (IRMS) analysis was performed to predict possible links between ETN samples and its precursors. Carbon, nitrogen, hydrogen and oxygen isotope ratios were determined for a wide variety of precursor sources and for ETN samples that were prepared with selected precursors. The stability of isotope ratios of ETN has been demonstrated for melt-cast samples and two-year old samples, which enables sample comparison of ETN in forensic casework independent of age and appearance. Erythritol and nitric acid (or nitrate salt) are the exclusive donor of carbon and nitrogen atoms in ETN, respectively, and robust linear relationships between precursor and the end-product were observed for these isotopes. This allowed for defining isotopic enrichment ranges for carbon and nitrogen that support the hypothesis that a given erythritol or nitrate precursor was used to synthesize a specific ETN batch. The hydrogen and oxygen atoms in ETN do not originate from one exclusive donor material, making linkage prediction more difficult. However, the large negative enrichments observed for both isotopes do provide powerful information to exclude suspected precursor materials as donor of ETN. Additionally, combing the isotopic data of all elements results in a higher discrimination power for ETN samples and its precursor materials. Combining the findings of our previously reported LC–MS analysis of ETN with this IRMS study is expected to increase the robustness of the forensic comparison even further. The partially nitrated impurities can provide insight on the synthesis conditions while the isotope data contain information on the raw materials used for the production of ETN. © 2020 The Authors
Topics
AttributionChemical profilingErythritol tetranitrate (ETN)ExplosivesForensic scienceHomemade explosiveIsotope ratio mass spectrometry (IRMS)PrecursorsCarbonErythritolErythrityl tetranitrateExplosiveHydrogen nitrateNitric acidNitrogen oxygenCemical analysisComparative studyForensic chemistryIsotope analysisIsotope ratio mass spectrometryLiquid chromatography-mass spectrometryMass spectrometrySynthesis
TNO Identifier
952536
ISSN
03790738
Source
Forensic Science International, 313
Publisher
Elsevier Ireland Ltd
Article nr.
110344