Analysis of Chemical Evidence

Gunshot residue can be found at near enough every case where a gun has been fired. When someone does pull the trigger on a gun a combustion reaction takes place which then results in gunpowder being released, this powder gets released backwards which means a lot of it will land on the forearm of the person who pulled the trigger and on the ground surrounding them. This gives the forensic analyst a good idea where the person was standing when they shot the gun and they can also do spot tests on the arms of the suspects for gunpowder.

The components inside the bullet cause this reaction to take place, most bullets contain:

• ·        Aluminium
• ·        Sulphur
• ·        Tin
• ·        Lead
• ·        Barium

The reaction that takes place when a gun is fired is a heat releasing exothermic reaction which results in chemicals being thrown everywhere. A residue gets discharged every time the gun gets fired, to find these residues forensic scientists would carry out spot tests to see if anything was present. Generally a spot test would be done to see if any of these components are present.

One of the main techniques used to identify drug samples in the lab is called spectrometry. Spectrometry is an analytical technique; it uses electromagnetic radiation to analyse chemical substances. These chemical substances will either absorb, emit or scatter electromagnetic radiation. A scientist can find out what the substance is by the spectra that is produced.

OJ Simpson

There was no chemical evidence actually found at the scene of the murder of Nicole Simpson and Ronald Goldman.