Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Mass Spectrometry Detection and Imaging of Organic and Inorganic Explosive Device Signatures using Desorption Electro-Flow Focusing Ionization



Thomas Forbes, Edward Sisco


We demonstrate the coupling of desorption electro-flow focusing ionization (DEFFI) with in-source collision induced dissociation (CID) for the mass spectrometric (MS) detection and imaging of explosive device components, including both organic, e.g., trinitrotoluene and nitroglycerin, and inorganic components, e.g., potassium chlorate and cesium, from the ever expanding assortment of homemade explosives and energetic materials. We utilize in-source CID to enhance ion collisions with atmospheric gas, thereby reducing adducts and minimizing organic contaminants. Optimization of in-source CID for the detection of organic and inorganic explosive device components demonstrated contrasting MS response relationships. The transition from electrospray to corona discharge chemical ionization and asymptotic approach to an emitted-current limited regime was identified and unaffected by the analyte classification. DEFFI-MS and in-source CID enabled isotopic and molecular speciation of inorganic components, providing further physico-chemical information. The developed system facilitated the direct detection and chemical mapping of trace analytes collected with Nomex® swabs and spatially resolved distributions within artificial fingerprints from forensic lift tape. The incorporation of alternating acquisition methods for negative and positive mode MS, and/or at high and low in-source CID, enabled the simultaneous detection and imaging of both organic and inorganic compounds. The results presented here provide the forensic and security sectors a powerful tool for the detection, chemical imaging, and inorganic speciation of explosives device signatures.
Analytical Chemistry


Mass spectrometry imaging, desorption electro-flow focusing ionization, ambient ionization, explosive detection, inorganic, artificial fingerprints, forensics, chemical analysis


Forbes, T. and Sisco, E. (2014), Mass Spectrometry Detection and Imaging of Organic and Inorganic Explosive Device Signatures using Desorption Electro-Flow Focusing Ionization, Analytical Chemistry, [online], (Accessed July 23, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created June 25, 2014, Updated November 10, 2018