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Fabrication and characterization of gelatin-based test materials for verification of trace contraband vapor detectors.

This work describes a method to produce inexpensive and field deployable test materials that can be used to verify the performance of trace contraband vapor detection systems such as ion mobility spectrometers (IMS) currently deployed worldwide for explosives, narcotics, and chemical warfare agent (CWA) detection. Requirements for such field deployable test materials include long shelf life, portability, and low manufacturing costs. Reported here is a method for fabricating these test materials using encapsulation of high vapor pressure compounds, such as methyl salicylate (MS), into a gelatin matrix. Gelatin serves as a diffusion barrier allowing for controlled and sustained release of test vapors. Test materials were prepared by incorporating serial dilutions of MS into gelatin, which provide controlled analyte vapor release over 3 to 4 orders of magnitude of instrument response. The test materials are simple to prepare and have been shown to be stable for at least one year under controlled laboratory conditions.