Trace evidence
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Trace evidence is evidence that is found at a crime scene in small but measurable amounts. Examples of typical trace evidence include hairs, fibers, soils, botanical materials, gunshot residue, explosives residue, and volatile hydrocarbons (arson evidence). The most common instrument used in trace evidence analysis is the compound polarized light microscope. Gunshot residue may be identified by elemental analysis using atomic absorption or with a scanning electron microscope equipped with an energy dispersive spectroscope. Small amounts of explosives, volatile hydrocarbons, and other chemicals are identified with the use of analytical instruments, such as gas chromatography, mass spectrometry, and infrared spectroscopy.
