Real-Time Hazardous Chemical Emission Rate Monitoring Instrument - Phase II.

Abstract : The purpose of this program was to develop a compact transportable monitor based on surface enhanced Raman spectroscopy (SERS) for detection of hazardous chemicals in an atmospheric environment. Our approach was to identify the adsorbates of hazardous chemicals by their vibrational spectra using SERS. The SERS spectrum is unique for each adsorbed species, can detect at the parts per million level, and can resolve gaseous mixtures. Raman spectroscopic techniques, such as SERS, are adaptable to fiber optics which serve to transfer laser light to and Raman scattering from remote sampling sites. Phase II continued research on hazardous gases of interest to the Air Force, particularly SO2, monomethyl hydrazine (MMH), unsymmetrical dimethyl hydrazine (UDMH), and NO2. In addition a complete compact prototype SERS system was fabricated and delivered to the Air Force for field deployments. The results of the Phase II program demonstrated that a practical compact SERS based monitor of hazardous gases at parts per million detection levels could be fabricated. The major advantages included real-time response, ppm detection limits and intrinsic safety. The Raman system developed can be generalized to a variety of applications, including waste analysis, groundwater analysis, biomedical testing, and online quality assurance.