RESUMO
A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source. Explosives and explosives-related vapors can be sourced through a number of means including gas cylinders, permeation tube ovens, dynamic headspace chambers, and a Pneumatically Modulated Liquid Delivery System coupled to a perfluoroalkoxy total-consumption microflow nebulizer. Key features of the TESTbed include continuous and pulseless control of trace vapor concentrations with wide dynamic range of concentration generation, six sampling ports with reproducible vapor profile outputs, limited low-volatility explosives adsorption to the manifold surface, temperature and humidity control of the vapor stream, and a graphical user interface for system operation and testing protocol implementation.
RESUMO
We have developed a universal structure and mechanism for the repeatable, rapid-attachment of a fluid cell to a planar substrate. The fluid cell and all fluidic connections are completely contained in a plastic body such that attachment requires neither adhesives nor modification of the substrate. The geometry of the fluid cell is defined by the active area of the planar substrate (e.g. a sensor array). All required components have been quickly prototyped using Computer Numerical Control (CNC) machining. It is also straight-forward to create an array of fluid cells to attach to a single substrate (e.g. a standard microscope slide). All components are easy to assemble and can be cleaned and reused, making this flexible approach applicable for a wide range of lab-on-a-chip applications.
