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

Determination of the dynamic nature of vapor/odor release has application in a wide variety of systems. This study applies automated solid-phase microextraction (SPME) utilizing an externally sampled internal standard (ESIS) to determine the vapor–time profile of odor delivery devices for three classes of explosive compounds. The profiles of delivery systems for target odorants 2,4-dinitrotoluene (2,4-DNT), 2-ethyl-1-hexanol (2-EH), and triacetone triperoxide (TATP) as canine training aids were compared over a period of 70 h. Strategies for evaluating the vapor–time profile of components with widely differing volatility are considered. An approach to quantifying the vapor concentration is described. The differences in the vapor–time profiles are examined and suggestions for selecting the best representative odor delivery technique are outlined.