A NIST standard reference material (SRM) to support the detection of trace explosives

Area of Science:

• Forensic Science
• Analytical Chemistry
• Materials Science

Background:

• Handling plastic and military explosives generates trace residues.
• Accurate detection and quantification of these residues are critical for security.
• Existing methods require reliable standards for calibration.

Purpose of the Study:

• To develop a Standard Reference Material (SRM) simulating trace explosive residues.
• To ensure the material is suitable for calibrating trace explosives detectors.
• To provide certified concentrations of explosives for analytical validation.

Main Methods:

• Coating chromatographic supports with Composition C-4 (RDX/HMX) and TNT.
• Selecting a base material (C18 silica) based on coating efficiency, extractability, stability, and particle size.
• Quantifying explosive concentrations using liquid chromatography with UV and MS detection (LC/UV, LC/MS).
• Testing the SRM on an ion mobility spectrometry (IMS) detector.

Main Results:

• SRM 2905 comprises four materials with two nominal concentrations (0.01% and 0.1% mass fraction) of C-4 and TNT.
• Octadecylsilane-modified silica (C18) with 20-30 micrometer particle size was selected as the base material.
• Certified concentrations were determined using validated LC/UV and LC/MS methods.

Conclusions:

• SRM 2905 provides a reliable standard for simulating explosive residues.
• The developed SRM is suitable for calibrating trace explosives detection systems.
• This standard enhances the accuracy and reliability of explosives detection in forensic and security applications.