Inkjet Metrology and Standards for Ion Mobility Spectrometry
R M. Verkouteren, J Brazin, Eric S. Windsor, Robert A. Fletcher, R Maditz, Wayne Smith, John G. Gillen
Piezoelectric inkjet nozzles offer precise control for dispensing small quantities of materials. NIST is developing inkjet metrology to provide reference materials, calibration services, and other standards for the IMS detection of trace contraband (explosives, narcotics, and chemical weapons) to support first responders and security screeners. Several piezoelectric systems are under development, and we will discuss the Vapor calibrator, the Jetlab II, and the Sphere-jet, which are designed to test and calibrate vapor detectors, swipe-based detectors, and portal-based detectors, respectively. The Vapor calibrator uses on-demand and continuous microdroplet injection and assisted evaporation to introduce trace explosive vapors into calibrated airstreams. With six nozzles able to inject different substances, vapor signatures may be produced at fg/L to ng/L levels. The Jetlab II is used to deposit known amounts of trace explosives and other substances in arrays on test surfaces, which can be swipes used to calibrate IMS detectors or items such as luggage handles used for training purposes. Arrays of thermochromic inks, formulated to change color at specific temperature thresholds, have been printed onto swipe surfaces to test the feasibility of a new generation of smart standard that can provide feedback to the user regarding effectiveness of the thermal desorption preceding IMS detection. The Sphere-jet generates solid monodisperse microspheres of polylactic-co-glycolic acid (PLGA) that contain trace amounts of butylated hydroxytoluene (BHT). IMS measurements of BHT-PLGA microspheres show peaks in positive and negative ion modes, which demonstrate usefulness for testing portals without contaminating the test area with trace explosives.
International Journal of Ion Mobility Spectrometry
, Brazin, J.
, Windsor, E.
, Fletcher, R.
, Maditz, R.
, Smith, W.
and Gillen, J.
Inkjet Metrology and Standards for Ion Mobility Spectrometry, International Journal of Ion Mobility Spectrometry
(Accessed March 4, 2024)