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Overcoming the limitations of explosives analysis by GC-MS with cold EI.

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Title: Overcoming the limitations of explosives analysis by GC-MS with cold EI.
Authors: Neumark, Benny1 (AUTHOR) benjaminn@mail.tau.ac.il, Amirav, Aviv1,2 (AUTHOR)
Source: International Journal of Mass Spectrometry. Feb2026, Vol. 520, pN.PAG-N.PAG. 1p.
Subjects: Explosives analysis, Gas chromatography/Mass spectrometry (GC-MS), Analytical chemistry, Statistical accuracy, Trace analysis, Electron impact ionization, Scientific method
Abstract: Explosives present significant challenges for chemical analysis. Traditional methods like High-Pressure Liquid Chromatography (HPLC) with UV/Vis detection often lack sufficient sensitivity and selectivity for complex matrices. HPLC coupled with Mass Spectrometry (MS) is also limited, as many explosives do not ionize efficiently with electrospray or atmospheric pressure chemical ionization. Gas Chromatography (GC) methods using Electron Capture Detection (ECD) or Mass Spectrometry (MS) with standard Electron Ionization (EI) also fall short. GC-MS with standard EI struggles due to thermal degradation at the injector and the hot metallic surface of the ion source and limited sensitivity. While GC-ECD can achieve lower detection limits, it lacks the selectivity of MS and poses safety risks due to its radioactive source. GC-MS with Cold Electron Ionization (Cold EI) offers a superior solution. Cold EI incorporates a supersonic molecular beam (SMB) interface, allowing contact-free ionization of vibrationally cold molecules. This enhances molecular ions, improves sensitivity, reduces noise, and expands the range of compounds amenable for GC-MS analysis. The result is faster, more selective, and sensitive analysis that is ideal for the full range of organic explosives. This study demonstrates the effectiveness of GC-MS with Cold EI for trace explosives analysis in soil. Using 17 explosive compounds listed in EPA Method 8095, we performed a complete method validation. The method's limits of detection were below 10 ng/g for all explosives, well below EPA thresholds for GC-ECD. GC-MS with Cold EI thus represents a significant advancement in mass spectrometry for forensic and environmental chemical analysis. [Display omitted] • GC-MS with Cold EI enables trace-level detection of 17 explosives listed in EPA 8330B, overcoming the limitations of standard GC-MS and LC-MS methods. • The supersonic molecular beam interface allows contact-free ionization of vibrationally cold molecules, enhancing molecular ions and improving selectivity and sensitivity. • The method achieved limits of quantification below 10 ppb for all explosives in soil matrices, meeting or exceeding regulatory thresholds. • Use of analyte protectants minimized injector degradation and improved SNR ratios, particularly for HMX. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:Explosives present significant challenges for chemical analysis. Traditional methods like High-Pressure Liquid Chromatography (HPLC) with UV/Vis detection often lack sufficient sensitivity and selectivity for complex matrices. HPLC coupled with Mass Spectrometry (MS) is also limited, as many explosives do not ionize efficiently with electrospray or atmospheric pressure chemical ionization. Gas Chromatography (GC) methods using Electron Capture Detection (ECD) or Mass Spectrometry (MS) with standard Electron Ionization (EI) also fall short. GC-MS with standard EI struggles due to thermal degradation at the injector and the hot metallic surface of the ion source and limited sensitivity. While GC-ECD can achieve lower detection limits, it lacks the selectivity of MS and poses safety risks due to its radioactive source. GC-MS with Cold Electron Ionization (Cold EI) offers a superior solution. Cold EI incorporates a supersonic molecular beam (SMB) interface, allowing contact-free ionization of vibrationally cold molecules. This enhances molecular ions, improves sensitivity, reduces noise, and expands the range of compounds amenable for GC-MS analysis. The result is faster, more selective, and sensitive analysis that is ideal for the full range of organic explosives. This study demonstrates the effectiveness of GC-MS with Cold EI for trace explosives analysis in soil. Using 17 explosive compounds listed in EPA Method 8095, we performed a complete method validation. The method's limits of detection were below 10 ng/g for all explosives, well below EPA thresholds for GC-ECD. GC-MS with Cold EI thus represents a significant advancement in mass spectrometry for forensic and environmental chemical analysis. [Display omitted] • GC-MS with Cold EI enables trace-level detection of 17 explosives listed in EPA 8330B, overcoming the limitations of standard GC-MS and LC-MS methods. • The supersonic molecular beam interface allows contact-free ionization of vibrationally cold molecules, enhancing molecular ions and improving selectivity and sensitivity. • The method achieved limits of quantification below 10 ppb for all explosives in soil matrices, meeting or exceeding regulatory thresholds. • Use of analyte protectants minimized injector degradation and improved SNR ratios, particularly for HMX. [ABSTRACT FROM AUTHOR]
ISSN:13873806
DOI:10.1016/j.ijms.2025.117564