Forensic toxicology is a specialty area of analytical chemistry (Forensic, 2004). Toxicology is the science of the adverse effects of chemicals on living organisms and a toxicologist detects and identifies foreign chemicals in the body, in particular toxic or hazardous substances. Forensic toxicologist 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 that may be helpful.
Because most substances entering the body are changed in some way by metabolism or other processes, a forensic toxicologist must be aware of all these possible changes when looking for a substance (Forensic, 2004). Specimens are first classified as acidic or basic fractions 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 two steps follow: screening tests, then confirmation tests (Forensic, 2004). Screening tests assay many specimens for a wide range of toxins in a short time, and any positive indications on screening tests are then verified with confirmation tests. Standard screening tests for toxins include: physical tests such as melting point, boiling point, density, and refractive index; crystal tests, which means 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, and is usually accepted as confirmation. Each toxin has a known mass spectra, which is infal...