Detection of Inorganic Salt-Based Homemade Explosives (HME) by Atmospheric Flow Tube-Mass Spectrometry

Area of Science:

• Analytical Chemistry
• Forensic Science
• Chemical Engineering

Background:

• Homemade explosives (HMEs) pose significant security risks.
• Sensitive detection methods are crucial for identifying explosive precursors.
• Current detection methods for HME oxidizers have limitations in sensitivity and scope.

Purpose of the Study:

• To develop and validate a sensitive method for detecting inorganic oxidizers in HMEs.
• To investigate the potential of atmospheric flow tube mass spectrometry for explosive detection.
• To explore the ionization chemistry and detection limits for various explosive oxidizer compounds.

Main Methods:

• Utilized a commercial mass spectrometer interfaced with an atmospheric flow tube (AFT).
• Employed thermal desorption coupled with dielectric barrier discharge ionization.
• Analyzed chlorate, perchlorate, and nitrate salts, including urea nitrate, guanidine nitrate, and potassium nitrate.

Main Results:

• Achieved picogram-level detection of inorganic oxidizers.
• Demonstrated sensitive detection of RDX vapor in the low parts per quadrillion range.
• Identified specific anions and salt adducts, providing insight into cation identity.
• Showcased direct room-temperature vapor detection for urea nitrate and hydrogen peroxide.
• Enabled room-temperature detection of chlorate and perchlorate salts via conversion to volatile acidic forms.

Conclusions:

• The AFT-mass spectrometry system provides a highly sensitive platform for detecting HME oxidizers.
• The method allows for the identification of specific explosive precursor compounds.
• This technique has potential applications in security and forensic analysis.