Nanoporous Metallic Structures for Concentrating Hazardous Vapors

Air toxins, whether industrial by products or terrorist releases, must be rapidly and accurately detected. The trace concentrations (generally ppb) that must be detected usually require sensitive analytical laboratory equipment. However, rapid and continuous field monitoring is preferable. To achieve this goal, a filter that rapidly concentrates the contaminants into a small sample volume and can be directly interrogated using a noninvasive, stand-alone device is desired. In this program, EIC Laboratories and Johns Hopkins University will develop novel nanoporous metallic substrates that can simultaneously concentrate the hazardous material into a small volume and then serve as the sample for optical evaluation. The techniques of Surface-Enhanced Raman (SERS) and Surface-Enhanced Infrared (SEIR) Spectroscopies can both provide ppb levels of detection for analytes adsorbed to roughened metal substrates. EIC has already demonstrate 5 ppb detection of explosive vapors on portable equipment in military field tests. In the current program, nanoporous gold will be produced through novel nanosynthetic and metallurgic procedures. The physical characteristics of the substrates, their adsorption coefficients for hazardous materials of interest, and SERS and SEIR spectra will be collected. The optimal substrates will be further developed and demonstrated in an air handling system that can emulate building flow rates.