Reproducible vapor-time profiles using solid-phase microextraction with an externally sampled internal standard

Area of Science:

• Analytical Chemistry
• Forensic Science
• Materials Science

Background:

• Understanding the dynamic release of vapors from odorants is crucial for various applications, including security and training.
• Odor delivery systems are vital for canine training aids, but their vapor release characteristics are not well-defined.

Purpose of the Study:

• To determine the vapor-time profiles of odor delivery devices for explosive compounds.
• To compare the performance of different delivery systems for 2,4-dinitrotoluene (2,4-DNT), 2-ethyl-hexanol (2-EH), and triacetone triperoxide (TATP).
• To provide guidance on selecting optimal odor delivery techniques.

Main Methods:

• Automated solid-phase microextraction (SPME) with an externally sampled internal standard (ESIS) was employed.
• Vapor-time profiles were measured for 70 hours for three target odorants.
• Strategies for analyzing compounds with varying volatility and quantifying vapor concentration were developed.

Main Results:

• Distinct vapor-time profiles were observed for the different explosive odorants and delivery systems.
• The study characterized the dynamic release of 2,4-DNT, 2-EH, and TATP over time.
• Differences in volatility significantly impacted the observed vapor release patterns.

Conclusions:

• The developed SPME-ESIS method effectively quantifies vapor concentration and profiles.
• Understanding these profiles is essential for designing effective canine training aids.
• The findings offer insights for selecting appropriate odor delivery systems based on compound volatility and desired release characteristics.