In this paper we describe BioLert II, an ultraviolet laser induced fluorescence (LIF) biological agent monitor for
detecting low concentrations of pathogens amid the ambient aerosol. BioLert II measures the fluorescence intensity and
size of individual particles, and computes the Degree of Threat (DoT), an indicator of the likelihood that a particular
threat material has appeared amid the recently sampled aerosol background. Performance is quantified using Receiver
Operating Characteristic (ROC) curves, which plot the relationship among threat concentration, probability of detection,
and false alert rate. We present BioLert II ROC curves for the detection of several simulated biological agents in an
environment of interest.
Portable fiber-optic Raman systems are being used to analyze chemical agents and other toxic chemicals in sealed glass containers. These containers include ampoules and bottles that are contents of chemical agent identification sets (CAIS) developed for use in training military personnel in chemical agent identification, safe handling, and decontamination. Real-time nonintrusive analysis of these sets is required so that the items containing chemical agents can be identified for proper disposal. This paper details the laboratory measurement of Raman spectra of chemical agents, Raman scattering cross sections of chemical agents, and the analysis of CAIS items in the field.
Imaging methodologies present some of the most exciting new frontiers in the biological and medical sciences. Raman spectroscopic imaging combines the power of chemical imaging with the spatial resolution for translating microscopic spectroscopic information into statements relevant to biological and medical function. Imaging results will be presented using mapping, dielectric filters, and liquid- crystalline tunable filters at different excitation wavelengths for selectively determining the spatial distribution of biomaterials in a variety of biological systems.
The importance of techniques to sense and monitor the environment are becoming increasingly more important with the intensifying presence of groundwater and soil contaminations. Our research and development effort is aimed at producing a commercial, low cost, field portable instrument for the field screening/in situ monitoring of contamination from organic solvents based on the principle of combining spectroscopic, electrochemical, and fiber optic techniques. Some of the advantages of this technique for monitoring a contamination site are cost, small size of sampling probe, real-time analysis, the capability of sensing in adverse environments, and the ability of using a central detection facility. The technique has an
advantage over current integrating fiber optic chemical sensing methods in that the sensing only takes place when the electrochemical device is turned on. This should enable long-term monitoring of a site to be accomplished with only one probe/instrument system.
Raman spectroscopy is a powerful noninvasive tool for elucidating chemical structure. Like infrared spectroscopy, it has many potential practical applications, such as process monitoring, environmental sensing, clinical analysis, forensic identification, and as a detector for use with analytical instruments. Until recently, however, Raman has been considered mainly in the context of basic research. The present generation of high performance Raman instruments tend to be large, complex and expensive, and thus have been of primary interest only to specialists in the field. This paper will discuss the development of a compact Raman spectrometer system consisting of a diode laser, fiber optics of excitation and collection, and a compact spectrograph with charge coupled device (CCD) detection.
This paper will evaluate the potential applications of SERS for bio- and biomedical sensing. The emphasis
willbe on technologies which will allow the development ofcost effective SERS instrumentation. Potential
techniques which can be adapted to fiber optic based sensing will also be discussed.