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.
B.
C.
D.
Definition of toxicology
Three areas of forensic toxicology
Role of the toxicologist
Toxicology vs. Pharmacology
II. All Substances are Poisons?
A. Therapeutic Levels
B. 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. 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.
B.
C.
D.
Types of cases
Specimens
Analytical Process
Analytes
FRSC 8104 – Toxicology Outline
VII.Human Performance Testing (Behavioral
Toxicology)
A. Steroids
1. Corticosteroids
2. Anabolic Steroids
3. Prohormones and Designer Steroids
Anabolic Steroids
Steroid Synthesis
Hormone Synthesis
Prohormones
FRSC 8104 – Toxicology Outline
B. Growth Hormones (HGH)
FRSC 8104 – Toxicology Outline
C. Alcohol (Ethanol)
1. Absorption of Ethanol
a.
b.
c.
d.
e.
Ingestion
Metabolism
Oxidation
Full vs. Empty
Stomach
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 Ethanol
3. Excretion of Ethanol
4. Circulation of Ethanol
a.
b.
Direct analysis of Blood
Alcohol content of Breath
5. Analysis of Ethanol
a.
b.
Field Sobriety Tests
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.
vi.
vii.
viii.
ix.
7.
Quantitative Analysis Procedures
External vs. Internal Standard
Plasma/serum
Reporting results
Sample Preservation (Anticoagulants and
Preservatives)
Alcohol Impairment
FRSC 8104 – Toxicology Outline
VIII.Workplace Drug Testing
A. NIDA – 5 classes of drugs
B. Test Types
1.
2.
3.
4.
5.
Urine
Saliva
Hair
Blood
Sweat (Patch)
SUBSTANCE
BLOOD
SALIVA
Shortest Detectability
SWEAT
URINE
---------------------------------->
HAIR
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
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
Cannabis (habitual
use)
http://www.erowid.org/psychoactives/testing/testing_info1.shtml
FRSC 8104 – Toxicology Outline
C. Classes of Drugs Tested
1.
Cannabanoids
Delta-9-THC
FRSC 8104 – Toxicology Outline
2.
Cocaine
FRSC 8104 – Toxicology Outline
3.
Amphetamines
Methamphetamine vs. Neurotransmitters
Methamphetamine
Dopamine
Epinephrine
FRSC 8104 – Toxicology Outline
4. Opiates
FRSC 8104 – Toxicology Outline
5.
Phencyclidine (PCP)
FRSC 8104 – Toxicology Outline
6.
Others
C. Methods of Analysis
1.
2.
Extraction Methods
Screening Methods
a.
3.
4.
5.
Immunoassay (EMIT, ELISA, RIA)
Confirmation
Field Tests
Special Considerations
At-Home Drug Test Kits
Drug
Screening
Urine
Cutoffs
Analyte Tested in
Confirmation
Confirmation
Urine Detection
Cutoffs (ng/mL) Time
(ng/mL)
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)
Methamphetamine
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