Forensic Chemistry and its Applications

What is Forensic Chemistry ?

Forensic chemistry is the branch of forensic science that deals with the analysis of unknown chemical substances found at the scene of the crime like explosives, drugs, accelerants, poisons, etc.

Forensic Chemistry

Forensic chemistry helps to link these substances with the suspect through different analytical techniques like HPLC, GC-MS, AAS, IR spectroscopy, FTIR, NMR Spectroscopy, etc. Moreover, the nature of these chemicals can also be identified by performing presumptive tests at the scene of the crime itself.

Application of forensic chemistry

  1. In the arson case investigation, the potential accelerants used in arson present on the debris can be analyzed through techniques like gas chromatography-Mass spectroscopy.
  2. Gunshot residue present on the scene of the crime or the clothes of the victim/suspect can be analyzed under the scanning electron microscope.
  3. Forensic chemists examine evidence like blood stains, and urine to find traces of drugs, toxins, or poisons. Paper or thin-layer chromatography can be used for the analysis of different toxins.

Types of samples received by a forensic chemist

1. Drugs

Drugs that are sized by law enforcement agencies are sent to a forensic chemist for a confirmatory test. By using techniques like gas chromatography, liquid chromatography, HPLC, etc. A forensic expert can tell the nature and properties of that drug.

2. Accelerants 

Accelerants are found on the debris in an arson case. The debris is collected in airtight containers and sent to a forensic chemist for analysis. Techniques like Gas chromatography-Mass spectrometry (GC-MS) are used to identify and quantitatively analyze the traces of ignitable liquid residing in collected samples.

3. Gunshot injuries

Gunshot residues and post-explosion debris like mixtures of primer and propellants are analyzed using a scanning electron microscope (SEM), Neutron Activation Analysis (NAA), and Energy Dispersive Spectroscopy (EDS).

4. Dye and Ink

The chemical analysis of dye and Ink is useful in the questioned documentation examination. It can help to link the suspect who wrote the document using that particular ink. Techniques like TLC, Gel electrophoresis is useful for the analysis of inks.

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