Toxicology is the study of the harmful effects of drugs and chemicals (poisons) on biological systems. It is a branch of science which deals with poisons. Poison is any substance that causes a harmful effect when administered, either by accident or intention, to a living organism.
Forensic toxicology is a sub-branch of forensic chemistry that applies the knowledge, principles, and methodologies associated with a specialized field of toxicology for the investigation before the criminal justice system.
Toxicology studies the harmful aspects of chemicals, poisons, and other toxic substances on humans and animals.
Role of Forensic Toxicology in Solving Crimes
Forensic toxicology deals with:
- Identification and quantification of the presence of drugs and chemicals in blood and tissue samples. Using chemical and biomedical instrumentation methods, detecting small amounts of toxic materials and how much is present.
- Determination of cause and manner of death.
- Study and determine the presence of poison or drug substances in the human or animal biological materials like blood, urine, vomit, viscera, and hair.
- Analysis of the unknown powder, pills, and medicinal capsules, tablets, syringes, and vials to find out their chemical identity.
- Recognize any plant alkaloids like nicotine, strychnine, croton, others in the tissues of the dead body.
- Determination of the quantity of alcohol in the blood, urine samples in drink and drive cases.
- The cause and effect of the poison on different parts of the body when taken via the skin, injection, and oral routes.
- Effect of the dose of a particular substance in causing detrimental impacts.
- Determines the fate of poison in the body.
- Identification of animal toxicants used for causing death like a scorpion, snake, fishes, insects, and other animals.
- Analysis of the post-mortem appearances.
Collection and Preservation of Toxicological Evidence
- Collection of biological or non-biological toxicology evidence.
- Biological material- Blood, vomit, saliva, stomach wash, intestine, nails, bones, brain, liver, kidney, teeth, lungs, spleen, hair, and cerebrospinal fluid.
- These biological pieces of evidence collected in glass bottles and paper envelopes.
- Non-biological materials- Suspected utensils and the food inside them.
- The evidence is collected and sealed with a polybag.
- Animal bite around the tissues or the bite mark should be collected.
Separation And Identification Techniques Used In Forensic Toxicology Laboratories
- The method varies with the type and quantity of the test sample available for separation and identification.
- Volatile poisons are extracted using the steam distillation process, and after that, identification is done by gas chromatography.
- Non-volatile organic poisons are treated with suitable solvents and then identified by Thin-Layer Chromatography and Gas Chromatographic techniques.
- Modern instrumental techniques such as HPLC (High-Performance Liquid Chromatography), gas chromatography combined with mass spectrometry (GC-MS), etc. These techniques can be used to identify and quantify the poison present in trace amounts.
- Other techniques like Radio-Immuno Assay (RIA) and Enzyme-Linked Immunosorbent Assay (ELISA) are used to identify drugs and poisons in biological materials such as blood, urine, and saliva, etc.
Forensic toxicologists play a vital role in investigating various substances to solve crimes or detect unlawful contamination in the environment, food, or water supply. They also analyze samples from bodily fluids and tissues to determine the presence or absence of harmful or intoxicating chemicals.