Forensic Toxicology Poisons Poison Any substance that can

Forensic Toxicology

Poisons Poison: Any substance that can harm or kill n Poison is generally used to hide the fact that a murder has occurred Toxicology: Study the adverse effects of chemicals on living organisms

Types of Poisoning Acute: Excessive single dose, or doses taken over a short interval of time Chronic: Smaller doses over a period of time Subacute: Features of both acute & chronic Fulminant: Massive dose, rapid death

Sources of Poison Domestic or household sources Agricultural or horticultural sources Industrial sources Commercial sources From uses as drugs and medicines Food and drink Miscellaneous sources

Suicide or Homicide? Suicidal poisons n n n Easily available No bad taste Cause no pain Cheap Highly toxic Capable of being taken with food or drink

Suicide or Homicide? Homicidal poisons n n n n Cheap Colorless, tasteless, odorless Highly toxic No residual product Signs and symptoms resembles natural diseases Capable of being administered with food or drink Defy detection Non-specific clinical syndrome

Factors that can influence poison: Quantity Physical form n n Gaseous/volatile Liquid vs. Solid Condition of the stomach Age State of body health Sleep

Signs & Symptoms: External Deep blue coloring: asphyxiant poisons Bright red/Cherry: CO & HCN Ulceration on lips: Corrosive poisons Stain near mouth: Nitric acid White froth from mouth & nose: Opium Injection marks: injections or bites Early decomposition: H 2 S

Signs & Symptoms: Internal Chalky appearance of teeth: H 2 S Blue lining in the gum: Lead Hard & leathery stomach wall: Formaldehyde Detectable stomach smell: Kerosene, alcohol, chloroform, opium Degeneration of the liver Swollen & reddish kidneys

Collections from the body: Blood Urine Part of both lungs Heart Brain Bones – Arsenic & Lead Nails – Arsenic Hair – Arsenic & Copper

Was it the spouse? Suspicious Behavior: n n n Wants dead spouse cremated ASAP Obsessed with financial matters History as plaintiff in employment disability claims and civil lawsuits

Was it arsenic? Marsh Test https: //www. youtube. com/watch? v=gt. Ibe 2 a. D 8 a 4

Definition of a Drug: A natural or synthetic substance that is used to produce physiological or psychological effects in humans or other higher order animals

Dependence Psychological Dependence: Emotional need of drug Physical Dependence: Physiological need for a drug. Characterized by withdraw sickness.

Narcotics Substances that bring relief from pain and produce sleep n Analgesics: Relieve pain by exerting a depressing action on the CNS Source: Opium

Narcotics/ Analgesics Common Drugs made from Opium: n n Heroin Codeine Common Drugs made from Opiates: n n Oxy. Contin Methadone

Hallucinogens Drugs that cause marked alterations in normal thought processes, perceptions, and moods

Hallucinogens Common Drugs n Marijuana More than 43 million Americans have tried it THC: Tetrahydrocannabinol Has medical usages

Hallucinogens Common Drugs Continued… n n n LSD: Lysergic acid diethylamide PCP: Phencyclidine “Angel Dust” Mescaline Psilocybin Ecstasy

Depressants Substance that depresses the functions of the central nervous system. They calm irritability and anxiety and may induce sleep.

Depressants Common Drugs n Alcohol - The most widely used and abused drug

Depressants Common Drugs Continued… n Barbituates (“downers”) Relax, create a feeling of well-being, and produce sleep Amobarbital, Secobarbital, phenobarbital, pentobarbital, butabarbital n Tranquilizers Produce a relaxing tranquility without impairment of high-thinking faculties or the inducement of sleep Valium

Depressants Common Drugs Continued… n “Glue Sniffing” Sniffing materials containing volatile solvents Aerosol gas propellants (freon) Airplane glue Model cement Damages the liver, heart, and brain Significant risk of death

Stimulants Substances taken to increase alertness or activity

Stimulants Common Drugs n Amphetamines (“Uppers, ” “Speed, ” “Ice, ” “Rocks”) Synthetic drugs that stimulate the central nervous system Produce feeling of well-being, increased alertness, decrease in fatigue, decreased appetite, restlessness/instability, apprehension Can also produce hallucinations, euphoria combined with hyperactivity, feeling of clarity of vision

Stimulants Common Drugs continued… n Cocaine Extracted from coca leaf One form is crack n Mix cocaine with baking soda and water Stimulates a pleasure center in the base of the brain in the area connected to nerves that are responsible for emotions

Club Drugs Synthetic drugs that are used at nightclubs, bars, and raves n MDMA (Ecstasy) Mind altering drug, increases self-awareness and decreases inhibitions n CNS Depressants GHB (Gamme hydroxybutyrate) n Dizziness, sedation, headache, nausea Rohypnol (Roofies) n Muscle relaxation, loss of consciousness, inability to remember Often connected with sexual assault, rape, robbery n Ketamine – veterinary drugs used by humans

Anabolic Steroids Synthetic compounds that are chemically related to the male sex hormone testosterone n n Promotes the development of secondary male characteristics and accelerates muscle growth Classified as controlled dangerous substances in 1991 Use is linked to liver cancer and liver malfunctions In females can cause masculinizing effects, infertility and diminished sex drive

Drug Identification Challenge: To select analytical procedures that will ensure a specific identification of a drug Two Phases of ID: n Screening Tests: Nonspecific, preliminary test Color Tests Microcrystalline Test n Pinpointing and confirming the drug’s identity Confirmation: A single test that specifically identifies a substance

Color Test

Microcrystalline Tests Add a drop of chemical reagent to a small quantity of the drug on a microscope slide View the crystalline precipitate under the microscope Advantages of this method: n n Rapid Do not require the isolation of dilutants

Microcrystalline Test

Marijuana Identification must be partially based on botanical features observed under the microscope by a trained expert Observe short hairs having the shape of bear claws on the upper side of the leaf – known as cystolithic hairs

Chromatography Thin Layer & Gas n n n Separate drugs from their diluents while providing for their tentative identification Comparison of retention time between questioned and known drugs Accompanies and complements color and crystal tests

Spectrophotometry Selective absorption of light by drugs in the UV and IR regions of the electromagnetic spectrum n UV spectrum is not conclusive for the positive ID of a drug Establishes a probable identity of a drug n IR (Infrared) can specifically identify a substance Pattern of the spectrum is unique to each compound and can be analogous to a fingerprint of a compound

Spectrophotometry

Mass Spectrometry Combine with chromatography = Gas Chromatography & Mass Spectrometry GC/MS As a sample emerges from the gas chromatograph it immediately enters the mass spectrometer Sample is then exposed to high-energy electrons, which cause the sample molecules to fragment or break apart n No two substances fragments in the same fashion Can ID each substance in a mixture

Gas Chromatography n Gas Chromatography – Separates mixtures on the basis of their distribution between a stationary liquid phase and a moving gas phase n Moving phase = gas (carrier gas) – Flows through a column of stainless steel or glass n Stationary phase = thin film of liquid – Packed column or capillary column

Gas Chromatography n The carrier gas flows through the column and carries along with it the components of the mixture – Components having greater attraction for the moving gas phase will move at a faster rate – Eventually the mixture will flow through the entire column and will be separated into its components n As each component emerges from the column it enters a detector (recorded in time per minute)

Mass Spectrometry n Each component flows into the MS as it emerges from the GC n Material enters a high-vacuum chamber where a beam of high-energy electrons is aimed at the sample molecules n Molecules break into fragments n Fragments pass through an electric or magnetic field where they are separated according to their masses

Mass Spectrometry n The unique feature of MS is that under carefully controlled conditions, no two substances produce the same fragmentation pattern – Fingerprint of the substance – Allows us to identify a chemical structure – Sensitive to minute concentrations n Connect the system to a computer

GC/MS

GC/MS