Performance metrics based on signal intensity for ion mobility spectrometry--based explosive trace detectors using...

Area of Science:

• Analytical Chemistry
• Materials Science
• Forensic Science

Background:

• Commercial off-the-shelf (COTS) explosive trace detectors (ETDs) are crucial for public and transportation security.
• Existing quality control methods for ETDs lack the precision to assess daily performance or inter-unit variability.
• A need exists for standardized, reliable test materials for ETD calibration and validation.

Purpose of the Study:

• To develop stable, precisely dosed test materials for explosive trace detection (ETD) quality control.
• To evaluate the performance and reproducibility of COTS ETDs using inkjet-printed test materials.
• To establish a foundation for routine performance monitoring of ETD instrumentation.

Main Methods:

• Utilized inkjet printing to create test materials with fixed dosing levels of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and pentaerythritol tetranitrate (PETN).
• Characterized the uncertainty in dispensed solute mass, achieving 0.8% for nominal doses (1 ng RDX, 5-20 ng PETN).
• Assessed the stability of test materials under various environmental conditions and their suitability for field use.

Main Results:

• Inkjet printing provided precise control over analyte distribution, minimizing signal variability.
• Test materials demonstrated stability for at least 20 days across relevant temperature ranges.
• Signal reproducibility for two COTS ETDs ranged from 6% to 15% relative standard deviation (RSD) over multi-year spans and multiple units.

Conclusions:

• Inkjet-printed test materials offer a reproducible and stable solution for explosive trace detector (ETD) quality control.
• The developed method enables reliable, day-to-day performance assessment and comparison of ETD units.
• Large datasets generated support the use of standard 3-sigma control practices for ETD performance monitoring.