New sampling methods for Raman handheld instruments

The realization of global terrorism after the September 11 attacks led immediately to a need for rapid field analysis of materials. Colorimetric test kits existed, but they are very subjective to interpret and they require contact with the sample. A push for handheld spectrometers quickly led to FTIR systems with ATR sampling, handheld IMS systems, and handheld Raman spectrometers. No single technique solves all of the problems of field detection. We will discuss the development of Raman instrumentation and, in particular, cover the advantages and the problems that are inherent in Raman portability. Portable Raman instrumentation began with a limited number of accessories: a point-and-shoot and some sort of vial adaptor. Currently this has expanded to stand-off attachments for measurements at a distance, air sampling to look for toxic gasses or aerosols, Orbital Raster Scan (ORS) to spatially average over samples, SERS attachments for trace detection, and fiber optic probes.