The application of toxicology for the purposes of the law. Greeks used hemlock as a means of state sponsored execution. Socrates was the most famous poisoning case by this method. 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.

1. Forensic Toxicology
• The application of toxicology for the purposes of the
law.
• Greeks used hemlock as a means of state sponsored
execution. Socrates was the most famous poisoning
case by this method.
• 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.

2. • The efforts or activities conducted to
effectuate this purpose include but are not
limited to the following:
• Urine testing to detect drug use
• Regulatory toxicology
• Occupational disease
• Identification of causative agents causing
death or injury in humans and animals

3. Postmortem Forensic Toxicology
 Suspected drug intoxication cases
 homicide
 Arson fire deaths
 Motor vehicle fatalities
 Deaths due to natural causes
 Death Investigations
–Coroner
–Medical Examiner

4. • Investigation of toxicity-related death/injury
• The basic phases in conducting an
investigation of a suspected toxicant-
induced/related death can be viewed as
follows:
• Collection of information and specimens
• Toxicological analysis
• Data interpretation

5. • The primary questions to be answered are
when conducting an investigation include:
• What was the route of administration?
• What was administered dose?
• Is concentration enough to have caused death
or injury or altered the victim’s behavior
enough to cause death or injury?

6. • Specimens should be collected before
applying processes that may destroy evidence,
that is before embalming.
• It is possible to obtain useful specimens from
burned or burial remains. The tissue often
collected under these circumstances include
bone marrow, skeletal muscle, vitreous humor,
hair, and maggots..

7. • For example, from hair samples, it is possible
to detect the presence of antibiotics,
antipsychotics, and drugs of abuse. However,
the information is primarily qualitative in
nature.
• From maggots, barbiturates, barbiturates,
benzodiazepines, phenothiazines, morphine,
and malathion can be detected

8. Postmortem Forensic Toxicology
• Specimens
– Blood –
– Vitreous humor
– Urine
– Bile
– Liver
– Other – lung, spleen, stomach contents or brain
– Hair

9. Drug Concentrations and Distribution
• As a rule, the highest concentrations of a
poison are found at the site of administration.
• A large quantity of drug in the GI tract and
liver indicates oral ingestion. The
gastrointestinal (GI) tract may contain large
amounts of unabsorbed toxicant.
• Cases that involve the oral administration of
toxicants indicate analysis of GI contents.

10. • Higher concentrations of drug or toxicant in
the lungs compared to other tissues may
indicate inhalation,
• while compounds located in tissue
surrounding an injection site indicates a fresh
intramuscular or intravenous injection
• Urine analysis is also of great value since the
kidney is the major organ of excretion for
most toxicants
• The liver is usually the first internal organ to
be analyzed.

11. Postmortem Forensic Toxicology
• Approximately 50-100 mL of blood should be collected.
• Blood from subdural or epidural clots should also be
collected.These specimens could be useful when there
is some period between an event and death.
• Vitreous humor displays good stability and resides in an
anatomically isolated area. Therefore it is more
resistant to putrefactive changes than are other
specimens.

12. Postmortem Forensic Toxicology…
 Analytical Process
• Separation
• Identification
• Confirmation
• Quantization

13. • There are different screens specific for the
type of substance to be assayed.
• A given laboratory will follow an algorithm to
handle the analysis.
• The Volatile Screen (VS) is frequently used for
the detection of ethanol.
• A Drugs of Abuse Screen (DAS) is commonly
used for amphetamines, cocaine, marijuana,
and so on.

14. • When the cause of death is unclear, a General
Drug Screen (GDS) is employed.
• Acidic/Neutral Screen (ANS) is primarily used
to detect barbiturates, muscle relaxants, and
so on.
• Basic Drug Screens (BDS) are more specific for
the detection of drugs such as cocaine and
antidepressants.
• It is recommended that the presence of a drug
or toxicant be verified in more than one
specimen.(check the word)

15. Human Performance Toxicology
• This branch of forensic toxicology is concerned with
the relationship between the presence of a drug and
associated behavioral changes.
• It is generally accepted that there is a dose-effect
relationship between drugs that elicit behavioral
changes and those changes; elucidation and
quantification of such a relationship is a significant
role of the behavioral toxicologist.
• Human performance toxicology is also referred to as
behavioral toxicology.
• E.g Ethanol and driving

16. Breath Ethanol Testing
 Chemical
• Reaction of ethanol with potassium
dichromate/sulfuric acid solution
• Oxidation reaction with a color change from yellow
(dichromate ion) to green (chromic ion)
 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

17. Immunoassay
• Has the ability to
determine small
concentrations of drugs
in body fluids and
organs
• Best approach for
detecting low drug
levels in body
• Usually used for
marijuana screening

18. Color Tests
• Most drugs react with certain
chemicals to produce a
specific color
• Marquis: purple in heroine,
opium. Orange brown in
(meth)amphetamines
• Dilli-Kopanyi: violet in
barbiturates
• Duquenois-Levine: purple for
marijuana
• Van Urk: blue purple in LSD
• Scott test: blue, pink and blue
for cocaine

19. Microcrystalline tests
• A small drop of a
chemical is added to a
small amount of drug
which forms a crystalline
structure
• Size and shape of crystal
can be used to identify
drug

20. Spectrophotometry
• Identifies drug on based on
the type of light it absorbs
• Infraredspectrophotometry
can identify a specific drug
because infrared spectrum
is unique for all drugs
• Other types of
spectrophotometry are
sometimes inconclusive

21. Other screening test
• Thermal Desorption
• Thin-Layer Chromatography (TLC)
• Gas Chromotography (GC
• High-Performance Liquid Chromatography
(HPLC)