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Forensic Toxicology. Analytical Toxicology Fall 2007. Forensic Toxicology. Toxicology is defined as the study of the adverse effects of chemicals on living organisms. Forensic toxicology is defined as the application of toxicology for the purposes of the law. Forensic Toxicology.

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Forensic Toxicology


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    1. Forensic Toxicology Analytical Toxicology Fall 2007

    2. Forensic Toxicology • Toxicology is defined as the study of the adverse effects of chemicals on living organisms. • Forensic toxicology is defined as the application of toxicology for the purposes of the law.

    3. Forensic Toxicology • Postmortem forensic toxicology. • Human performance toxicology. • Forensic drug testing.

    4. History • Ancient Egyptians and Grecians reported poisonings due to herbs, plants and food. • Opium, arsenic and hydrocyanic acid were used throughout Europe during the middle ages.

    5. History • Philippus Theophrastus Aureolus Bombastus von Hohenheim (or Paracelsus) observed that any substance could be a poison, depending on its dose • “ What is there that is not poison? All things are poison and nothing without poison. Solely the dose determines that a thing is not a poison”

    6. History • In 1814, M.J.B. Orfila, the chairman of the legal medicine department at the Sorbonne in France, published a book entitled Traite des poisons ou Toxicologie Generale.

    7. History • In 1851, Stas developed the first effective method for extracting alkaloids from biological specimens. • This was modified several years later by Otto, which enabled the isolation of purer alkaloid substances.

    8. History • In the U.S., forensic toxicology did not develop until the early 20th century. • Dr. Alexander Gettler is considered this country’s first forensic toxicologist.

    9. Postmortem Forensic Toxicology • Suspected drug intoxication cases • Homicides • Arson fire deaths • Motor vehicle fatalities • Deaths due to natural causes

    10. Postmortem Forensic Toxicology • Death Investigations • Coroner • Medical Examiner

    11. Postmortem Forensic Toxicology • Specimens • Blood – from the heart and from the femoral or jugular veins • Vitreous humor • Urine • Bile • Liver • Other – lung, spleen, stomach contents or brain

    12. Postmortem Forensic Toxicology • Analytical Process • Separation • Identification • Confirmation • Quantitation

    13. Postmortem Forensic Toxicology • Analytes • Volatiles (Carbon Monoxide, Cyanide, and Alcohols) • Drugs • Metals

    14. EHTANOL (1.787 min.) 2-PROPANOL (2.804 min.) ACETALDEHYDE (1.414 min.) ACETONE (2.462 min.) MEK(ISTD) (5.584 min.) 0 6

    15. Postmortem Forensic Toxicology • Drugs • One Comprehensive Approach:

    16. Postmortem Forensic Toxicology • Metals • Aluminum • Arsenic • Iron • Mercury • Lead • Thallium

    17. Postmortem Forensic Toxicology • Metals (continued) • Analysis • Colorimetric • Graphite Furnace Atomic Absorption Spectrometry • Inductively Coupled Plasma – Mass Spectrometry • Neutron Activation Spectrometry

    18. Human Performance Toxicology • Human performance toxicology is also referred to as behavioral toxicology. • It is the study of human performance under the influence of drugs.

    19. Human Performance Toxicology • Ethanol and driving • History • Behavioral effects • Specimens

    20. Ethanol Toxicology • Types of alcohol • Ethanol (ethyl alcohol) • Methanol (methyl alcohol) • Isopropanol • Ethylene glycol

    21. Ethanol Toxicology • Ethanol production • Fermentation of sugar or starch • Can only achieve 20% ethanol • Distillation • Distilled alcoholic beverages are usually 40 to 50% ethanol by volume (80-100 proof)

    22. Ethanol Pharmacokinetics • Absorption • Means of absorption • Dermal • Inhalation • IV • Oral • Gastrointestinal tract • Presence of food.

    23. Ethanol Pharmacokinetics • Distribution • Gastrointestinal tract • Portal vein • Liver • Heart • Lung • Heart • Body

    24. Ethanol Pharmacokinetics • Elimination • 5-10% in the urine • Saliva, expired air and sweat • Liver (enzymatic oxidation to acetaldehyde, acetic acid and carbon dioxide)

    25. Ethanol Effects on the Body • Cardiovascular system • Central nervous system • Gastrointestinal tract

    26. Ethanol Effects on the Body • Kidney • Liver

    27. Breath Ethanol Testing • Theory • Henry’s law • Ethanol in breath Vs ethanol in blood • 2100 to 1 ratio • 2300 to 1 ratio

    28. Breath Ethanol Testing • Types of analyzers • Chemical • Reaction of ethanol with potassium dichromate/sulfuric acid solution • Colored solution that results is measured spectrophotometrically • IR spectrophotometry • Electrochemical oxidation - fuel cell

    29. Breath Ethanol Testing • IR Spectrophotometry • Based on absorbance of light by the ethanol molecule • Mainstay in evidential breath testing devices • Electrochemical Oxidation • Oxidation of ethanol to acetic acid • Also used in evidential breath testing

    30. Blood Ethanol Testing • Chemical • Screening • Quantitative • Disadvantage - aldehydes and ketones will interfere with the test

    31. Blood Ethanol Testing • Enzymatic • Conversion of NAD to NADH by ethanol (serum, urine and whole blood) • Measured spectrophotometrically at 340 nm • Same reaction with a blue dye (thiazoyl blue) (serum, urine, fresh blood and postmortem blood) • Measured with a fluorometer

    32. EHTANOL (1.787 min.) 2-PROPANOL (2.804 min.) ACETALDEHYDE (1.414 min.) ACETONE (2.462 min.) MEK(ISTD) (5.584 min.) 0 6 Blood Ethanol Testing • Gas Chromatography • Can measure ethanol in a wide range of specimens • Can distinguish ethanol from other alcohols, aldehydes and ketones • Two common methods • Head space • Direct injection

    33. Assessment of Ethanol Impairment • In a British study: • Detectable deterioration of drivers at between 30 – 50 mg/dL • Obvious deterioration observed at between 60 – 100 mg/dL • In another British study: • Pilots exhibited impairment at 40 mg/dL

    34. Assessment of Ethanol Impairment • Blood alcohol concentration: • 10-50 mg/dL: Impairment detectable by special tests • 30-120 mg/dL: Beginning of sensory-motor impairment • 90-250 mg/dL: Sensory-motor incoordination; impaired balance • 180-400 mg/dL: Increased muscular incoordination; apathy; lethargy

    35. Assessment of Ethanol Impairment • Blood alcohol concentration: • 250-400 mg/dL: Impaired consciousness; sleep; stupor • 350-500 mg/dL: Complete unconsciousness; coma • 450 and greater mg/dL: Death from respiratory arrest

    36. Human Performance Toxicology • Drugs and driving • DEC program • Drug recognition expert • Toxicologist • Prosecution

    37. Human Performance Toxicology • Drug Recognition Evaluation - 12 Step Process • Breath alcohol test • Interview of the arresting officer. • Preliminary examination of the suspect. • Examination of the eyes. • Divided attention psychophysical tests. • Vital signs examination.

    38. Human Performance Toxicology • Drug Recognition Evaluation (continued) • Dark room examination. • Examination of muscle tone. • Examination for injection sites. • Suspect’s statements and other observations. • Opinion of the evaluator. • Toxicological examination.

    39. Human Performance Toxicology • Drug Recognition Evaluation

    40. Human Performance Toxicology Drug Recognition Evaluation

    41. Human Performance Toxicology • Drug Recognition Evaluation (continued) • Toxicology • Type of Testing • Specimens

    42. Human Performance Toxicology • Drug Recognition Evaluation (continued) • Drug Class Effects • Central Nervous System Depressants • Central Nervous System Stimulants • Hallucinogens • Phencyclidine • Narcotic Analgesics • Inhalants • Cannabis

    43. Forensic Drug Testing • Introduction • History • Military • Criminal justice system • Public sector • Private sector • Rationale

    44. Forensic Drug Testing • Uses in the workplace: • Pre-employment screening • Post-accident testing • Return to Work testing • “For Cause” testing • Random testing

    45. Forensic Drug Testing Military Experience

    46. Forensic Drug Testing President Ronald Reagan 1986 Executive Order No. 12564 Objective: To develop a “drug-free” workplace.

    47. Forensic Drug Testing Mandatory Guidelines for Federal Workplace Drug Testing Programs

    48. Forensic Drug Testing Mandatory Guidelines Laboratory Accreditation Specified Menu & Cutoffs Proficiency Testing Inspections External Blind Controls Corrective Actions