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AnalyticForensic Toxicology Ch 31
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Analytic/Forensic. Toxicology Ch 31. By. Amber Smith. Introduction ... Most simply measured by Gas Chromatography. Volatile Substances ... – PowerPoint PPT presentation
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Title: AnalyticForensic Toxicology Ch 31
1
Analytic/ForensicToxicology Ch 31
- By
- Amber Smith
2
Introduction
- Analytic ToxicologyInvolves application of the
tools of analytic chemistry to the qualitative or
quantitative estimations of chemicals that may
exert adverse effects on living organisms - Forensic ToxicologyThe use of toxicology for
purposes of the law
3
Analytic Toxicology
- Encompasses all chemical substances
- Gases
- Volatile Substances
- Corrosive Agents
- Metals
- Anions and Nonmetals
- Nonvolatile Organic Substances
- Miscellaneous
4
Gases
- Most simply measured by Gas Chromatography
5
Volatile Substances
- Generally consists of liquids of a variety of
chemical types - Measured by Gas-Liquid Chromatography for
separation and quantitation
6
Corrosives
- Includes mineral acids and bases
- Detected by clinical chemical techniques
7
Metals
- Encountered as occupational and environmental
hazards - Separation procedures involve the destruction of
the organic matrix by chemical or thermal
oxidation
8
Toxic Anions and Nonmetals
- May be trapped in combination with a stable
cation - Can be separated by dialysis and are detected by
Chromatagraphic procedures and Ion-Specific
Electrodes
9
Nonvolatile Organic Substances
- The largest group of substances
- Includes prescribed and illegal drugs,
pesticides, natural products, pollutants, and
industrial compounds - Detected through immunoassay procedures
10
Miscellaneous
- Includes venoms and other toxic mixtures of
proteins - Detects most practically by immunoassay procedures
11
Role in General Toxicology
- Monitoring dosage forms or solutions for
stability throughout the course of an experiment - Important in establishing the bioavailability of
a compound under study
12
Role in Forensic Toxicology
- Postmortem Investigations
- Cause of death in poisoning cases
- Presence of intoxicating of ethanol in car
accidents - Carbon Monoxide detection
- Provide data for substance abuse
- Assist in cause of death for a court of law
13
Toxicologic Investigation of a Poison Death
- 3 steps
- Obtaining case history and suitable specimens
- Toxicologic analyses
- Interpretation of Analytic findings
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Case History and Specimens
- Collect facts
- Gross autopsy findings
- Drugs available to the decedent
- Interval between the onset of symptoms and death
- Analyses performed
- Analyzed Specimens
15
Toxicologic Analyses
- Factors to consider
- Amount of specimen available
- Nature of the poison sought
- Possible biotransformation of the poison
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Toxicologic Analyses
- Organs Analyzed
- Gastrointestinal contents
- Urine
- Liver
17
Toxicologic Analyses
- Problems
- Hydrolysis, oxidation or reduction of proteins,
nucleic acids, or lipids that may generate
compounds that interfere with identification
18
Toxicologic Analyses
- Testing
- Ferric chloride, perchloric, and nitric adic
color test for phenothiazine drugs and
immunoassays for the detection of amphetamines,
benzodiazepines, and opiates in the urine - GC/MC or HPLC is most widely used for most drug
identification
19
Interpretation of Analytic Results
- Provides answers
- Route of Administration
- Dosage and if of toxicant present is enough
to cause death or alter action enough to cause
death - Tests on blood, tissue, and plasma
- Results are often used to corroborate
investigative findings
20
Criminal Poisoning of the Living
- GC/MS HPLC tests are used for 2 types of
poisoning - Administration of drugs to incapacitate victims
of kidnapping, robbery, or sexual assault - Poisoning as a form of child abuse deliberate
administration of toxic or injurious substances
to a child, usually by a parent of other caregiver
21
Forensic Urine Drug Testing
- Urine is the only specimen analyzed and is only
tested for a limited number of drugs - Testing consists of immunoassays
- Sample is checked for adulteration by checking
the pH, creatine, specific gravity, and for any
unusual color or smell
22
Human Performance Testing
- Tests for ethanol and chemicals in blood, breath,
or other specimens that may modify performance of
behavior - Common application for DUI and DUID
- Alcohol related accidents are responsible for
55-65 of fatalities in drivers
23
Courtroom Testimony
- Toxicologist is an expert witness providing an
objective testimony and opinion - Objectiveinvolves desciption of his or her
analytic methods and findings - Opinionhow the person interprets the results
24
Role in Clinical Toxicology
- Used to identify the nature of the toxic exposure
and measure the amount of the toxic substance
that has been absorbed - Also monitoring the amount of the toxic agent
remaining in circulation or measuring what is
excreted
25
Role in Therapeutic Monitoring
- Determine individual variability to drugs by
- Rate and extent of drug absorption
- Distribution and binding in body tissues and
fluids - Rate of metabolism and excretion
- Pathologic conditions
- Interaction with other drugs
26
Role in Biologic Monitoring
- Monitor workers directly for exposure
- Exposures are to a mixture of compounds
- Must be able to measure minute of the
compound - Measure changes of normal metabolites induced by
xenobiotics
27
References
- Klaassen, C.D. 2001. Casarett Doulls
Toxicology The Basic Science of Poisons. New
York, NY. McGraw-Hill Companies Inc.
28
Questions
- What are 4 of the 7 substances measured by an
Analytic Toxicologist? - What are the 3 steps used for toxicologic
investigation of a poison death?
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