title: Direct analysis in real time mass spectrometry of potential by-products from homemade nitrate ester explosive synthesis.
abstract: This work demonstrates the coupling of direct analysis in real time (DART) ionization with time-of-flight mass spectrometry (MS) in an off-axis configuration for the trace detection and analysis of potential partially nitrated and dimerized by-products of homemade nitrate ester explosive synthesis. Five compounds relating to the synthesis of nitroglycerin (NG) and pentaerythritol tetranitrate (PETN) were examined. Deprotonated ions and adducts with molecular oxygen, nitrite, and nitrate were observed in the mass spectral responses of these compounds. A global optimum temperature of 350 °C for the by-products investigated here enabled single nanogram to sub nanogram trace detection. Matrix effects were examined through a series of mixtures containing one or more compounds (sugar alcohol precursors, by-products, and/or explosives) across a range of mass loadings. The explosives MS responses experienced competitive ionization in the presence of all by-products. The magnitude of this influence corresponded to both the degree of by-product nitration and the relative mass loading of the by-product to the explosive. This work provides a characterization of potential by-products from homemade nitrate ester synthesis, including matrix effects and potential challenges that might arise from the trace detection of homemade explosives (HMEs) containing impurities. Detection and understanding of HME impurities and complex mixtures may provide valuable information for the screening and sourcing of homemade nitrate ester explosives.
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Science Division, Gaithersburg, MD 20899, United States. Electronic address: edward.sisco@nist.gov.
authors.forename: Edward
authors.initials: E
authors.lastname: Sisco
authors.affiliation: National Institute of Standards and Technology, Materials Measurement Science Division, Gaithersburg, MD 20899, United States.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Forbes
keywords: Direct analysis in real time; Explosives; Forensic science; Mass spectrometry; Nitrate esters
references.citation: J Pharm Sci. 1983 Feb;72(2):194-6
references.pmid: 6403694
references.citation: Analyst. 2015 Apr 21;140(8):2785-96
references.pmid: 25717497
references.citation: Forensic Sci Int. 2013 Oct 10;232(1-3):160-8
references.pmid: 24053876
references.citation: Forensic Sci Int. 2013 Jul 10;230(1-3):37-45
references.pmid: 23622790
references.citation: J Mass Spectrom. 2005 Oct;40(10):1261-75
references.pmid: 16237663
references.citation: Forensic Sci Int. 2013 Mar 10;226(1-3):10-21
references.pmid: 23498998
references.citation: J Chromatogr A. 2002 Nov 15;977(1):59-68
references.pmid: 12456095
references.citation: J Am Soc Mass Spectrom. 2004 Oct;15(10):1416-23
references.pmid: 15465354
references.citation: Anal Bioanal Chem. 2014 Jan;406(1):63-80
references.pmid: 24036523