Toxicology Lab Activity

*Analysis of Drugs and Poisons

*Objectives

*Identify some common over-the-counter drugs

*Note: The actual drugs will be used for these tests

*Learn how to test for some “controlled drugs”

*Note: Simulations will be used for the controlled drugs. Substances that will act the same way for a test will be substituted for the actual drug.

*Test for heavy metals (lead and mercury)

*Background

*Drug: any substance used as a medicine internally or externally

*Narcotics: drugs that are habit forming

*Usually relieve pain, induce sleep, or cause death when taken in excess

*Regulated by Federal law—i.e. Controlled drugs

*A drug is considered a poison if when taken in excessive amounts it causes illness or death

*At the crime scene….

*Search for evidence of drug or poison use:

*Empty glasses or bottles

*Medicine containers

*Traces of powder or liquids on the body, clothes, carpet or floor

*Note: it is always easier to test an empty container for traces of poison than a body

*Tests used….

*Chromatography

*Spectrophotometry

*Mass spectrometry

*Spot tests with chemical reagents

*Note: We will use the last test in this lab

*Over-The-Counter Drugs

*Over-the-counter drugs can cause accidental poisonings

*Examples

*Alcohol

*Antacids

*Nicotine

*Aspirin

*Pain Relievers

*Aspirin = acetylsalicylic acid

*Ferric nitrate is used to test for the presence of aspirin. When mixed, the aspirin hydrolyzes to form salicylic acid and acetic acid. The ferric ion reacts with the salicylic acid to form a purple colored compound that is easily identified.

*Acetaminophen = Tylenol

*Relieves pain without being acidic

*Antacids

*Alka-Seltzer

*Contains sodium bicarbonate, citric acid and a very small amount of aspirin. Reacts with water to produce carbon dioxide gas and a buffer.

*Sodium bicarbonate

*Reacts to neutralize stomach acid according to the following equation:

NaHCO3 + HCl NaCl + H2O + CO2

*Experiment 1

*Stop: Do Experiment #1

*Controlled Drugs

*Hallucinogenic Drugs = LSD, Marijuana, Heroine, Cocaine.

*Most are white powder alkaloids (nitrogen containing plant products having marked physiological action when given to animals)

*Most are identified by the colored precipitates they form with specific reagents.

*Most will also fluoresce under UV light

*LSD

*LSD = Lysergic Acid Diethylamide

*Alkaloid from ergot (a fungus found on rye and cereal)

*Can be made synthetically

*50 micrograms taken orally produces psychosis and brain disturbances.

*Will fluoresce under UV light

*Will form a yellow precipitate with potassium chromate

*Marijuana

*Marijuana = Cannabis sativa

*Only mind-bender that does not contain nitrogen

*Most widely used illegal drug

*Visual identification under a microscope reveals small crystals of calcium carbonate at the base of the leaf hairs.

*HCl will bubble and produce carbon dioxide gas when dropped on a leaf

*Experiment 2

*Stop: Do Experiment #2

*Heavy Metal Poisons

*Poisons in general withhold the oxygen necessary for life processes to continue from the tissues.

*Various sources exist in the environment:

*Car exhaust

*Pesticides

*Medicines

*Industrial wastes

*Lead Poisoning

*Lead: found in batteries, paint, gasoline, ceramic glazes, among others

*Affects the functioning of the blood, liver, kidneys and brain

*Dose of 0.5 g can be fatal

*Lead will form a yellow precipitate when mixed with potassium chromate

*Mercury Poisoning

*Mercury: found in electric apparatuses, thermometers, batteries, medicines, fungicides for seeds, industrial waste and contaminated fish.

*Affects brain tissues and destroys the neurons.

*Causes blindness, convulsions, mental retardation and death

*Dose of 1g is fatal

*Experiment 3

*Stop: Do Experiment #3