In the field of forensic sciences, handheld Raman spectrometers are used by the military and first responders for the rapid identification of unknown substances. These unknown materials include toxic industrial chemicals (TICs), toxic industrial materials (TIMs), chemical warfare agents, explosives, narcotics, pharmaceutical compounds, and plastics. However, Raman spectroscopy has historically been problematic for the identification of biological samples, such as bacteria, growth media, and tissues. Sample fluorescence typically overwhelms Raman scattering by several orders of magnitude, resulting in a high background and poor spectral matching.
In this study, the feasibility of fluorescence background subtraction using a handheld spectrometer to differentiate several bacterial growth media, specifically in the presence and absence of bacteria was investigated. As SERS is often not practical for first responders and military personnel (because of time constraints, limited dexterity in personal protective equipment, and ease of use), a portable Raman spectrometer that utilizes a proprietary algorithm to subtract background fluorescence was tested. This baseline correction capability may allow for the interrogation of biologic materials that would otherwise “swamp” traditional handheld Raman instruments used in forensic analyses.
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