Evaluating headspace component vapor-time profiles by solid-phase microextraction with external sampling of an internal standard.

William MacCrehan, Stephanie Moore, Michele Schantz

Index: Anal. Chem. 83(22) , 8560-5, (2011)

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Abstract

The vapor-time profiles of explosive materials are of valuable interest to Homeland Security, providing critical information that can aid in the detection of explosive-containing devices. An approach is described that achieves reproducible characterization of volatile components as a function of time based on comparison of the sample response to an externally sampled internal standard (ESIS). Utilizing nonequilibrium solid-phase microextraction (SPME) measurements, this SPME-ESIS technique improves reproducibility (reported as percent relative standard deviation) of vapor-time profiles by approximately an order of magnitude and allows for an equitable comparison of the target compound between diverse materials. Two odorants associated with canine detection of explosives, 2-ethyl-1-hexanol and 2,4-dinitrotoluene, are used to optimize parameters for the SPME-ESIS technique.