title: Evaluating headspace component vapor-time profiles by solid-phase microextraction with external sampling of an internal standard.
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.
authors.affiliation: Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States. william.maccrehan@nist.gov
authors.forename: William
authors.initials: W
authors.lastname: MacCrehan
authors.forename: Stephanie
authors.initials: S
authors.lastname: Moore
authors.forename: Michele
authors.initials: M
authors.lastname: Schantz
mesh_terms: D004136:Dinitrobenzenes / Q000032:analysis* / Q000592:standards; D000441:Hexanols / Q000032:analysis* / Q000592:standards; D012015:Reference Standards; D052617:Solid Phase Microextraction / Q000592:standards; D013997:Time Factors; D014835:Volatilization
chemical_list: D004136:Dinitrobenzenes; D000441:Hexanols; C016403:2,4-dinitrotoluene; C034017:2-ethylhexanol