Crime Scene Forensics – Determining the Chemical Composition of Trace Evidence
When studying trace evidence found at the crime scene, forensic scientists use in their arsenal tools other than microscopes at their disposal. Using the following methods, which are the most commonly used ones, forensic scientists can ascertain the chemical characteristics of trace evidence. This helps them find out if the tested samples are the same and thus share the same origin.
- Infrared (IR) Spectrophotometry: This laboratory method requires exposing samples of trace evidence to infrared radiation. Different samples absorb infrared light at different wavelengths. It is these differences that discern the one sample from another.
- Neutron Activation Analysis: This method is a bit cumbersome and requires the use of a nuclear reactor. Neutrons are fired at the sample and collide with its components. The result is that each component releases radiation at its own unique energy level. By measuring the levels of those radiation emissions, the forensic scientist can reveal the chemical characteristics of the sample. This procedure is very useful in studying paint, hair, metals, soil, and many other samples.
- X-ray Diffraction: In this laboratory technique, X-rays are shot at objects or materials. The way the X-ray beams scatters displays how atoms and molecules in the sample are arranged. The arrangement of these atoms and molecules in a sample is referred to as a chemical fingerprint of the sample. This laboratory technique is useful in studying trace evidence such as paint and soil.
By using these laboratory techniques to study trace evidence such as paint chips, forensic scientists can come one step closer in solving a crime based on the evidence left at the crime scene.
Forensic science can help bring the offender to justice.
With advances in science, crooks are less likely to get away with crimes such as murder or assault. There is a big demand for criminalists who can analyze trace evidence so that they can testify in court and put the perpetrator behind bars, and, in some cases, bring closure to the family of the murder victims.
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