chapter fourteen – forensic toxicology frsc 8104 criminalistics ii professor bensley
TRANSCRIPT
Chapter Fourteen – Forensic Toxicology
FRSC 8104Criminalistics II
Professor Bensley
FRSC 8104 – Toxicology Objectives1. 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 Objectives6. 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 OutlineI. Introduction
A. Definition of toxicologyB. Three areas of forensic toxicologyC. Role of the toxicologistD. Toxicology vs. Pharmacology
II. All Substances are Poisons?A. Therapeutic LevelsB. Lethal Dose (LD50)
Typical Dose Response Curve
(NOAEL) = No observed adverse effect level
(LOAEL) = Lowest observed adverse effect level
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. DistributionC. MetabolismD. Elimination
FRSC 8104 – Toxicology Outline
IV. Pharmacodynamics – Study of how drugs act in the body
A. Receptors, Agonists, and AntagonistsB. ToleranceC. Synergism
FRSC 8104 – Toxicology OutlineV. Sample/Specimen Collection
VI. Post Mortem Forensic ToxicologyA. Types of casesB. SpecimensC. Analytical ProcessD. Analytes
FRSC 8104 – Toxicology OutlineVII.Human Performance Testing (Behavioral
Toxicology)A. Steroids
1. Corticosteroids2. Anabolic Steroids3. Prohormones and Designer Steroids
Anabolic Steroids
Steroid Synthesis
Hormone Synthesis
Prohormones
FRSC 8104 – Toxicology OutlineB. Growth Hormones (HGH)
FRSC 8104 – Toxicology OutlineC. Alcohol (Ethanol)
1. Absorption of Ethanola. Ingestionb. Metabolismc. Oxidationd. Full vs. Empty
Stomache. Factors determining
absorption rate
Ethanol Oxidation
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 Ethanol3. Excretion of Ethanol4. Circulation of Ethanol
a. Direct analysis of Bloodb. Alcohol content of Breath
5. Analysis of Ethanola. Field Sobriety Testsb. Breath Tests (BrAC)
FRSC 8104 – Toxicology Outlinei. Breathalyzer
FRSC 8104 – Toxicology Outlinec. Blood Alcohol Concentration (GC-FID)
i. Extractionii. Distillationiii. Direct Injection of blood or serumiv. Head Space Procedures
FRSC 8104 – Toxicology Outlinev. Quantitative Analysis Proceduresvi. External vs. Internal Standardvii. Plasma/serumviii. Reporting resultsix. Sample Preservation (Anticoagulants and
Preservatives)7. Alcohol Impairment
FRSC 8104 – Toxicology OutlineVIII.Workplace Drug Testing
A. NIDA – 5 classes of drugsB. Test Types
1. Urine2. Saliva3. Hair4. Blood5. Sweat (Patch)
SUBSTANCE BLOOD SALIVA SWEAT URINE HAIR Shortest Detectability - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > Longest Detectability
Alcohol 12 hrs 6-12 hrs unknown 6-24 hrs n/a
Amphetamine 12 hrs 3 days unknown 1-4 days up to 90 days
Barbiturates unknown unknown unknown 1-21 days unknown
Benzodiazepines unknown unknown unknown 1-42 days unknown
Cannabis (single use) 2-3 days 12-24 hrs unknown 2-3 days up to 90 days
Cannabis (habitual use) 2 weeks 12-24 hrs unknown 15-30 days up to 90 days
Cocaine unknown 1 day unknown 4-5 days up to 90 days
Codeine/Morphine unknown 12-36 hrs unknown 2-4 days up to 90 days
Heroin unknown unknown unknown 2-4 days up to 90 days
Methamphetamine 1-3 days unknown unknown 3-5 days up to 90 days
PCP 1-3 days 3 days unknown 3-7 days up to 90 days
http://www.erowid.org/psychoactives/testing/testing_info1.shtml
FRSC 8104 – Toxicology OutlineC. Classes of Drugs Tested
1. Cannabanoids
Delta-9-THC
FRSC 8104 – Toxicology Outline2. Cocaine
FRSC 8104 – Toxicology Outline3. Amphetamines
Methamphetamine vs. NeurotransmittersMethamphetamine
Dopamine Epinephrine
FRSC 8104 – Toxicology Outline4. Opiates
FRSC 8104 – Toxicology Outline5. Phencyclidine (PCP)
FRSC 8104 – Toxicology Outline6. Others
C. Methods of Analysis1. Extraction Methods2. Screening Methods
a. Immunoassay (EMIT, ELISA, RIA)
3. Confirmation4. Field Tests5. Special Considerations
At-Home Drug Test Kits
Drug Screening Urine Cutoffs (ng/mL)
Analyte Tested in Confirmation
Confirmation Cutoffs (ng/mL)
Urine Detection Time
Amphetamine 1,000 Amphetamine 500 2-4 days
Cocaine 300 Benzoylecgonine 150 1-3 days
Heroin 300 Morphine;6-monoacetylmorphine
300;10 1-3 days
Marijuana 50-20 Tetrahydrocannabinol 15 1-3 days (casual), 30 days (chronic)
Methamphet-amine
1,000 Methamphetamine;Amphetamine
500; 200 2-4 days
PCP 25 Phencyclidine 25 2-7 days (casual)
http://www.nida.nih.gov/pdf/monographs/monograph167/108-129_Cone.pdf