The Forensic Services Chemistry Section of the National Forensic Science Technology Center (NFSTC) evaluated the Smiths Detection RespondeRTM Raman spectrometer, which is currently used by law enforcement, border patrol officers, military personnel, and other first responders to chemically characterize unknown solids, liquids, pastes, gels, and powders encountered in field environments.
Among the strengths of this instrument are that testing does not destroy the sample and can be accomplished through sample vials, ensuring the integrity of the evidence. In addition, up to 10 results are listed as matches and include their spectra and "hit" quality scores between zero and one (the user can set the "hit" quality threshold for returning results). Other desirable features are the incorporation of software into the instrument and a user option to perform a residual search on any of the listed matches. Limitations of the instrument are its inability to render accurate or reproducible results for the identification of common drugs such as cocaine base, methamphetamine, heroin, morphine, and codeine. Also, the identification of a compound in a mixture did not necessarily correspond with the compound in the highest ratio in the mixture. Generally, Raman spectroscopy does not work with trace evidence, since a sufficient quantity of the compound of interest must be available for sampling. Also Raman spectroscopy does not work well on highly fluorescent or pigmented items. Health and safety issues are discussed, along with areas for improving the instrument. The evaluation included assessments of conformity; reproducibility; mixture sensitivity; specificity; portability; ruggedness; and ease of use, including sample preparation, library additions, and training requirements. Appended tabular data