Presentation on theme: "Chapter Fourteen – Forensic Toxicology FRSC 8104 Criminalistics II Professor Bensley."— Presentation transcript:
Chapter Fourteen – Forensic Toxicology FRSC 8104 Criminalistics II Professor Bensley
FRSC 8104 – Toxicology Objectives 1.Describe the role of the forensic toxicologist in the following: Postmortem Examinations, Human Performance Testing, and Workplace Drug Testing. 2.Describe the various biological matrices on which toxicological analyses are routinely performed. 3.Explain how alcohol is produced, how it is absorbed into the bloodstream, how it is transported throughout the body, and how it is eliminated by oxidation and excretion. 4.Describe the basic fundamental concepts of breath alcohol testing procedures (BrAC). 5.Relate the precautions to be taken to properly preserve blood samples in order to accurately analyze its alcohol content.
FRSC 8104 – Toxicology Objectives 6.Describe techniques that forensic toxicologists use to isolate and identify drugs and poisons. 7.Appreciate the significance of finding a drug in human tissues and organs to in relation to assessing level of impairment.
FRSC 8104 – Toxicology Outline I.Introduction A.Definition of toxicology B.Three areas of forensic toxicology C.Role of the toxicologist D.Toxicology vs. Pharmacology II.All Substances are Poisons? A.Therapeutic Levels B.Lethal Dose (LD 50 )
FRSC 8104 – Toxicology Outline III.Parmacokinetics – Study of how drugs move into and out of body A.Absorption - All introduction methods result in passage of drug through a tissue barrier and into the bloodstream B.Distribution C.Metabolism D.Elimination
FRSC 8104 – Toxicology Outline IV.Pharmacodynamics – Study of how drugs act in the body A.Receptors, Agonists, and Antagonists B.Tolerance C.Synergism
FRSC 8104 – Toxicology Outline V.Sample/Specimen Collection VI.Post Mortem Forensic Toxicology A.Types of cases B.Specimens C.Analytical Process D.Analytes
Ethanol Absorption (Widmark) Curve The effect of food on blood alcohol concentration. The graph shows BAC after a person drank alcohol following an overnight fast (solid line) and immediately after breakfast (dotted line).
FRSC 8104 – Toxicology Outline 2.Distribution of Ethanol 3.Excretion of Ethanol 4.Circulation of Ethanol a.Direct analysis of Blood b.Alcohol content of Breath 5.Analysis of Ethanol a.Field Sobriety Tests b.Breath Tests (BrAC)
FRSC 8104 – Toxicology Outline i.Breathalyzer
FRSC 8104 – Toxicology Outline c.Blood Alcohol Concentration (GC-FID) i.Extraction ii.Distillation iii.Direct Injection of blood or serum iv.Head Space Procedures
FRSC 8104 – Toxicology Outline v.Quantitative Analysis Procedures vi.External vs. Internal Standard vii.Plasma/serum viii.Reporting results ix.Sample Preservation (Anticoagulants and Preservatives) 7.Alcohol Impairment
Drug Screening Urine Cutoffs (ng/mL) Analyte Tested in Confirmation Confirmation Cutoffs (ng/mL) Urine Detection Time Amphetamine1,000Amphetamine days Cocaine300Benzoylecgonine days Heroin300Morphine; 6-monoacetylmorphine 300;101-3 days Marijuana50-20Tetrahydrocannabinol151-3 days (casual), 30 days (chronic) Methamphet- amine 1,000Methamphetamine; Amphetamine 500; days PCP25Phencyclidine252-7 days (casual)