Forensic Evidence Examination
Microspectrophotometers are used for forensic evidence examination to compare fibers, paints, soils, glass, plastic and questioned documents..
UV-visible-NIR absorbance spectra of three single textile fibers.
Microspectrophotometers are used to examine microscopic amounts of forensic evidence.
Forensic evidence examination is the field of forensic science that relates to the examination of evidence. One of the most common types is trace evidence: this field covers everything from textile fibers, glass and plastic fragments, paint chips and smears, soils and much more. It is the job of the forensic scientist to determine if a known and a questioned sample are from the same source. Another, but more difficult task, is to determine the source of an unknown sample. Often tests are done by comparison with other original samples or by comparison with standard reference materials.
Many types of tests can be performed by the forensic scientist on forensic evidence. Many of these tests are determined by the type of evidence that is being examined. Due to the microscopic nature of most trace evidence, microspectrophotometers such as the 20/30 Forensic™ are commonly found in forensic laboratories. This system is able to provide both images and spectra of microscopic features of any type of trace evidence in the ultraviolet, visible and near infrared regions. The visible part of the spectrum is important as it helps distinguish between different colors found in trace evidence. The UV is important as many of the colorants used also have a UV active component. The NIR region is important as there may be important sample variations observed here. A 20/30 PV™ will allow the forensic scientist to take both images and microspectra™ in UV, color and NIR.
Raman microspectroscopy is growing in its importance in the forensic lab. It is able to identify materials and functional groups of much smaller samples than a standard FTIR microspectrometer. The Apollo Raman Spectrometer™ is designed to add this capability to the microscope.
Glass is another common type of trace evidence. The rIQ™ system intelligently measures the refractive index of the small glass fragments. When integrated with a microspectrophotometer, the color and fluorescence of the glass may also be measured.
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