Testing for drugs in the lab Drugs & crime Testing for drugs in the lab

What are drugs? A drug is considered to be any substance used either internally or externally as a medicine. It can have an effect on the function or structure of living tissue through various chemical reactions Some drugs are habit forming – these are classified as narcotics

Types of Drugs Over-the-Counter: medicines that may be obtained by a consumer without a prescription from a doctor Controlled Drugs: a drug or medicine that is held under strict governmental control due to its strong potential for abuse or addiction. These often include narcotics. Illicit Drugs: drugs that are not legally permitted

Forensics Application Drug identification can be instrumental in various criminal cases such as… Deliberate Poisoning Homicide Accidental Death Suicide It is important to determine right away if a drug or poison played a role in the crime – search bodies, clothing, possessions, trash receptacles for any sign of poison/drugs.

Drugs as evidence There must be no questions regarding drug evidence when it is presented in court. If a substance is identified, it must be further classified as illicit or over-the-counter. Even the form of the drug may be important for sentencing in a case.

Over-the-counter Even over-the-counter drugs can be important in forensic cases. Though they are purchased easily, they can still be dangerous – especially in cases or accidental poisoning or death. Aspirin Acetaminophen Alka-Seltzer

aspirin Acetylsalicylic Acid – synthetic pain reliever The most widely used drug in the world Ferric Nitrate – an acidified solution – is used to detect aspirin. Aspirin hydrolyzes to form salicylic acid and acetic acid, and the ferric ion reacts with the salicylic acid to form a compound with a characteristic purple color.

acetaminophen Tylenol – non-acidic, and a good pain reliever for those allergic to aspirin. Also reacts with ferric ions to create a characteristic color when present.

antacids Alka-Seltzer – used to treat hyperacidity Contain carbonates (like sodium bicarbonate – found in pop) that neutralize the acid to produce salt, water, and CO2. Alka-Seltzer also reacts with ferric nitrate because it contains a small amount of aspirin.

Hallucinogenic drugs Drugs that disrupt normal brain function, impairing the thought process, communication, and the ability to focus on reality. LSD Marijuana Alkaloids – basic nitrogen Heroin containing plants, white powders, Cocaine marked physiological effects

Testing for hallucinogens Most alkaloids can be identified by the colored precipitates they form with specific reagents. Observations under various types of light or the use of chromatography can also be useful. **Most hallucinogenic drugs are fluorescent, so they glow under UV light. If a drug tests positive for fluorescence, it then will undergo thin-layer chromatography to further determine its makeup.

Testing for Marijuana Marijuana is the only hallucinogen that does not contain nitrogen. Usually, tested under a microscope for visual identification – small crystals of calcium carbonate found along leaf hairs and small stems. When hydrochloric acid is added to marijuana, effervescence occurs (production or CO2 bubbles) Duquenois-Levine Test – definitive test – when mixed with marijuana and shaken, the solution will turn pink, then violet, and then blue upon standing.

Heavy metal poisons Lead and arsenic used to be the most common heavy metals used in poisoning cases. Today, we have seen an increase in heavy metal poisoning due to mercury, cadmium, and copper. Lead – affects functioning of blood, liver, kidney, and brain. Deposited in the bones over a period of time. Even a dose of 0.5g can be fatal. Mercury – concentrates in brain tissues and destroys neurons, causing blindness, convulsions, mental retardation, and even death. A dose of 1.0g is fatal.

Testing for metals Both lead and mercury damage proximal renal tubules of the kidney, resulting in a large amount of characteristic amino acids in the urine. Paper or thin-layer chromatography tests are run with urine samples and are compared to known Rf values of amino acids. Mercury Lead Excretion of glycine Excretion of alanine and B-aminoisobutyric acid