Forensic scientists work in the area of forensic toxicology, a specialty area of analytical chemistry, to identify or compare matter and categorize it as organic or inorganic (Forensic, 2004). Toxicology is the science of the deleterious effects of chemicals on living organisms and a toxicologist detects and identifies foreign chemicals in the body. Forensic toxicologists usually receive samples for analysis as preserved samples of body fluids, stomach contents, and body parts. They have access to coronerÆs reports, which will give them any signs and symptoms and postmortem data which may be helpful.
Most substances entering the body are changed in some way by metabolism or other processes, and a forensic toxicologist must be aware of all these possible changes when examining forensic samples (Forensic, 2004). Specimens are first classified as acidic or basic for drug extraction from body tissue or body fluids, e.g. barbiturate drugs are acid-soluble, whereas amphetamine drugs are base-soluble. Compounds are often derivatized so they can be more easily detected by the analytical tests.
After the preliminary acid/base procedures, the tissue or fluid sample is now a drug sample, and screening tests are performed, followed by confirmation tests (Forensic, 2004). Screening tests allow scientists to assay many specimens for a wide range of toxins in a short period of time, and any samples which are positive on screening tests are then subjected to confirmation tests. Screening tests for toxins include: physical tests such as melting point, boiling point, density, and refractive index; crystal tests, which involves treatment with chemicals to produce crystals; chemical spot tests, which involves treatment with chemicals to note color changes; and thin-layer or gas chromatography to separate components in a mixture. The confirmation test is usually mass spectrometry, which combines gas chromatography and mass spectrometry,...