Chemistry of
Forensic Science
Chapter 7
FACT! In the UNITED STATES
75 % of the evidence being
examined in forensic
laboratories is considered drug
related, either the drugs
themselves or evidence from
drug related crimes.
Chapter 7
Drugs and Crime
 A drug is a natural or synthetic substance designed to
affect the subject psychologically or physiologically.
 “Controlled substances” are drugs that are restricted by
law
 The Controlled Substances Act is a law that was enacted
in 1970; it lists illegal drugs, their category and their
penalty for possession, sale or use.
Chapter 7
2
Drug-Control Laws
• The Controlled Substances Act illustrates a
drug-classification system created to prevent
and control drug abuse
• 5 classifications/schedules of drugs are
created based upon the following criteria.
– potential for abuse
– potential for physical and psychological
dependence
– medical value
Chapter 7
Controlled Substances Act

Schedule I—high potential for abuse; no currently acceptable medical use in the
US; a lack of accepted safety for use under medical supervision

heroin (diacetylmorphine), LSD, marijuana, ecstasy (MDMA)
•

Schedule II—high potential for abuse; a currently accepted medical use with
severe restrictions; abuse may lead to severe psychological or physical
dependence


We will not be discussing medical marijuana, If you are interesting in this topic please research it
on your own time.
cocaine, morphine, amphetamines (including methamphetamines), PCP, Ritalin
Schedule III—lower potential for abuse than the drugs in I or II; a currently
accepted medical use in the US; abuse may lead to moderate physical dependence
or high psychological dependence

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intermediate acting barbiturates, anabolic steroids, ketamine
4
Controlled Substances Act
 Schedule IV—low potential for abuse relative to drugs in III; a
currently accepted medical use in the US; abuse may lead to limited
physical or psychological dependence relative to drugs in III
 other stimulants and depressants including Valium, Xanax,
phenobarbital, Darvon
 Schedule V—low potential for abuse relative to drugs in IV; currently
accepted medical use in the US; abuse may lead to limited physical or
psychological dependence relative to drugs in IV
 codeine found in low doses in cough medicines
Chapter 7
5
Identification of Drugs
 PDR—Physicians’ Desk Reference
 Field Tests—presumptive tests
 Laboratory Tests—conclusive tests
Chapter 7
6
Physicians’ Desk Reference
PDR—a physicians’ desk reference is
used to identify manufactured pills, tablets
and capsules. It is updated each year.
This can sometimes be a quick and easy
identifier of the legally made drugs that
may be found at a scene.
The reference book gives a picture of the
drug
Tells whether it is a prescription, over the
counter, or a controlled substance
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7
Human Components
Used for Drug Analysis
 Blood
 Urine
 Hair
Chapter 7
 Liver tissue
Most
commonly
used
 Brain tissue
 Kidney tissue
 Gastric Contents
 Spleen tissue
 Bile
 Vitreous Humor of
the Eye
8
Drug Identification
Presumptive tests
 Color tests
 Chromatography
Confirmatory tests
 Spectrophotometry
 Ultraviolet (UV)
 Visible
 Infrared (IR)
 Crystal tests – When a
reagent is added to an
unknown drug certain crystals
will begin to form
Chapter 7
9
Presumptive Color Tests
 Marquis—turns purple in the presence opium
derivatives and orange-brown with
amphetamines
 Dillie-Koppanyi—turns violet-blue in the
presence of barbiturates
 Duquenois-Levine—turns a purple color in
the presence of marijuana
 Van Erk—turns a blue-purple in the presence
of hallucinogenic drugs such as LSD
 Scott test—turns blue in the presences of
cocaine
Chapter 7
10
Drug Identification
• The challenge of forensic drug identification is
selecting the proper analytical technique so
that the drug can be properly identified
• This plan for identifying unknown drugs is
divided into two phases.
1. Screening test: reduce the possibilities to a
testable number.
2. Confirmation test: specifically identifies a
substance.
Chapter 7
Qualitative vs. Quantitative
• Another consideration in selecting an
analytical technique is the need for either a
qualitative or a quantitative determination.
– Qualitative – shows the identity of the material
– Quantitative – shows the percent composition
of the components of a mixture. (How pure is
the illicit substance?)
Chapter 7
Chromatography
A technique for separating mixtures into their
components
 Stationary phase—paper
 Mobile phase—a liquid solvent
If the Rf value for an unknown
compound is close to or the same
as that for the known compound, the
two compounds are likely similar or
identical (a match).
Chapter 7
13
Confirmatory Tests: Spectroscopy
Spectroscopy—the interaction of electromagnetic radiation with
matter
Spectrophotometer—an instrument used to measure and record
the interaction of electromagnetic radiation with matter
Chapter 7
Chapter 7
Infrared Spectrometry
1. Material placed in the spectrophotometer may or may not absorb
energy in the IR region of the electromagnetic spectrum
2. Compares the IR light beam before and after it passes through a
transparent sample
3. Gives a unique view of the substance; like a fingerprint
Chapter 7
Function Groups and
Absorptions
Functional Group
Aklyl
Type of Absorption
C – H stretch
Absorption Information (cm-1)
2950 – 2850 (m or s)
C – H stretch
3100 – 3010 (m)
C = C stretch
C – H stretch
1680 – 1620 (v)
~3300 (s)
C ≡ C stretch
2260 – 2100 (v)
C – H stretch
~3030 (v)
C – H bend
860 – 680 (s)
C = C bend
1700 – 1500 (m, m)
O – H stretch
3550 – 3200 (broad, s)
O – H stretch
3000 – 2500 (broad, v)
C = O stretch
1780 – 1710 (s)
Amine
N – H stretch
3500 – 3300 (m)
Nitrile
C ≡ N stretch
2260 – 2220 (m)
Aldehyde
C = O stretch
1740 – 1690 (s)
Ketone
C = O stretch
1750 – 1680 (s)
Ester
C = O stretch
1750 – 1735 (s)
C = O stretch
1690 – 1630 (s)
N – H stretch
3700 – 3500 (m)
Alkenyl
Alkynyl
Aromatic
Alcohol/Phenol
Carboxylic Acid
Amide
Common IR spectra
Chapter 7
Common IR spectra
Chapter 7
Common IR spectra
Chapter 7
Common IR spectra
Chapter 7
LD 50 :
What is the LETHAL Dose?
What is the lethal dose for 50% of the population?
– Most often these tests are done on animals (rats, mice, dogs,
monkeys and then humans)
– Various methods for intake are also taken, whether it be
inhalation, orally, subcutaneously, intravenously
– When LD 50 are determined for humans there is not one lethal
dose for all due to variations in body chemistry
– A graph is made based upon body mass in kilograms
Chapter 7
Forensic Toxicology
• Toxicology studies the adverse effects of chemicals or
physical agents on living organisms
• A forensic toxicologist may:
– Determine the affects of alcohol consumption on an individual
involved in a car accident
– Determine whether a death was due to poisoning or overdose
– Assess the effect of drugs on someone’s actions during a crime
Chapter 7
During a Toxicology Report…
The Toxicologist must answer these 3 questions
1. Are any drugs present?
2. If so, what drugs are there?
3. What concentrations of drugs can be found?
Chapter 7
Toxic substances may
•
•
•
•
Chapter 7
Be a cause of death
Contribute to death
Cause impairment
Explain behavior
Drug Concentrations
• Any drug concentration will fall within one of 4 categories:
Normal: found in the general population
Therapeutic: level bringing about the most beneficial effect,
typically for prescription drugs
Toxic: may cause harm, nausea, vomiting, death
Lethal: at this level, the drug will consistently cause death
Chapter 7
Words of Wisdom
“All substances are
poisons; there is none
which is not a poison.
The right dose
differentiates a poison
from a remedy.”
-Paracelsus
Chapter 7
Dosage is important but…
• Things to consider
Chemical or physical form of the
substance
How it enters the body
The body weight and physiological
conditions of the victim including age
& sex
Time period of exposure
Were other chemicals present in the body
Chapter 7
Dose Makes the Poison
• Matthew Carrington, 21, had a heart attack and
died during “Hell Week,” authorities said, as he
was in the final stages of a months long process
to rush Chi Tau fraternity.
• Carrington’s friend who survived the hazing told
police that he and Carrington both were forced to
drink about five gallons of water.
Chapter 7
Toxicity Classification
LD50 (rat,oral)
Correlation to Ingestion
by 150-lb Adult Human
Toxicity
<1 mg/kg
a taste to a drop
extreme
1–50 mg/kg
to a teaspoon
high
50–500 mg/kg
to an ounce
moderate
500–5,000 mg/kg
to a pint
slight
5–15 g/kg
to a quart
practically nontoxic
Over 15 g/kg
more than 1 quart
relatively harmless
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Chapter 7
Federal Regulatory Agencies
Food and Drug Administration (FDA)
Environmental Protection Agency (EPA)
Consumer Product Safety Commission
Department of Transportation (DOT)
Occupational Safety and Health Administration (OSHA)
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Chapter 7
Symptoms of Various Types of Poisoning
Type of Poison
Symptom/Evidence
Caustic poison (lye)
Characteristic burns around the lips and
mouth of victim
Red or pink patches on the chest and
thigh, unusually bright red lividity
Black vomit
Greenish-brown vomit
Yellow vomit
Coffee-brown vomit, onion or garlic odor
Burnt almond odor and bluish skin
Extreme diarrhea
Nausea and vomiting, unconsciousness
possibly blindness
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Carbon monoxide
Sulfuric acid
Hydrochloric acid
Nitric acid
Phosphorus
Cyanide
Arsenic, mercury
Methyl (wood) or isopropyl
(rubbing) alcohol
Chapter 7
Some Lethal Dose Values
Material
LD50 mg/kg (rats,
oral)
Material
LD50 mg/kg (rats,
oral)
Sucrose
29,700
Dioxin
0.020
Vitamin C
11,900
Botulin toxin
0.000005 – 0.00005
Ricin
0.020
Aluminum chloride
3,311
Ethanol
7,060
Magnesium chloride
8,100
Methanol
5,628
Nickel chloride
105
Lead acetate
4,665
Cobalt chloride
80
Sodium bicarbonate
4,220
Arsenic chloride
48
Bismuth chloride
3,311
Arsenic trioxide
14.6
Caffeine
192
Arsenic pentoxide
8
Sodium chloride
3,000
Mercuric chloride
1
Maganese chloride
1,484
VX (nerve agent)
0.060
Arsenic
Chapter 7 metal
763
Antimony chloride
525
Historical Perspective of Poisoners
Olympias—a famous Greek poisoner
Locusta—personal poisoner of Emperor Nero
Lucretia Borgia—father was Pope Alexander VI
Madame Giulia Toffana—committed over 600 successful poisonings,
including two popes
Hieronyma Spara—formed a society to teach women how to murder
their husbands
Madame de Brinvilliers and Catherine Deshayes—French poisoners
AND many others through modern times.
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Chapter 7
Narcotics
Are analgesics, a substance that affects the central nervous
system to relieve pain.
– Mild analgesics are found in many OTC drugs such as
aspirin, acetaminophen (Tylenol), ibuprofen (Advil/Motrin)
Illicit narcotics come from opium
– havested from a particular type of poppy flower grown
mostly in Asia
Opium contains 4 – 21% morphine, often used medicinally
as a powerful painkiller
–
Heroin is easily made from morphine and is highly
addictive
Codeine is commercially prepared from morphine and is
often found in OTC drugs in Canada, in the U.S. a
Chapter 7
prescription is needed.
All from Opium
Opium
comes from
the milky
fluid in the
ripe seed
bulb on the
opium
poppy. It is
estimated
that in 2007
Afghanistan
supplied
92% of the
world’s
illicit
production
Chapter 7
Morphine
Heroin
“Black Tar” Heroin
Hydrocodone
Chapter 7
Chapter 7
Stimulants
Act on the central nervous
system to increase
energy & alertness while
suppressing appetite and
fatigue
– The downside…as soon as
the drug wears off there is
restlessness & anxiety
– Stimulants can range from
very mild, like caffeine (coffee
& tea) to very strong like
methamphetamines
Chapter 7
Cocaine
• Comes from the leaves of the coca
plant, grown most exclusively on
the Amazon slopes of the Andes
mountains
– It takes 500 pounds of coca leaves to
produce 1 pound of cocaine powder
• Highly addictive
• Can cause anxiety, insomnia and
weight loss, in addition to mental
deterioration
• LD50 – 0.0341g/kg in male mice
when consumed orally
Chapter 7
Cocaine powder
In Yemen, drug dependency
grows
Chapter 7
Hallucinogens
Mostly naturally occurring substances that can change normal
thought processes, perceptions and moods.
• In the U.S.
– marijuana, a plant that has been used for medicine, to make
rope (hemp) and to produce euphoria for thousands of years
• Active ingredient: THC, tetrahydrocannabinol
• Decreases the uses ability to concentrate, slows reactions
and impair coordination
Chapter 7
LSD (d –lyseric acid
diethylamide)
Chemically derived a fungus that grows on grain.
As little 25 ug (micrograms), can cause visual and
auditory hallucinations.
– Often found on blotters paper (pg 169 in text)
– As tiny color tablets – microdots
– Or on pieces of dried gelatin – window panes
Impairs memory and attention span
A known teratogen (agent that can cause birth
defects in an embryo or fetus)
Chapter 7
Salem Witch Trials and LSD
• Ergot is a fungus that infects the grain of rye plants
in cold weather
• It has been suggested that the visions that the girls
of Salem, Massachusetts experienced were due to
eating tainted rye
• Twenty towns people were executed
Chapter 7
PCP (phencyclidine)
Was once used as a intravenous anesthetic (pain
killer) but was taken off the market due to strange
side effects
•
•
•
•
•
Chapter 7
Insensitivity to pain
Feelings of super strength
Rage
Memory loss
Paranoia
MDMA (methylenedioxymethamphetamine
or “ecstasy”)
Synthetic (man-made) drug that both stimulates the
user and causes hallucinations
– Confusion, depression, addiction, severe anxiety, and
paranoia can result only after a week of use
– Heart rate and blood pressure increase on ecstasy
and can lead to death very quickly
Use of MDMA can lead to very permanent damage to
the parts of the brain that are important to memory
Chapter 7
Ketamine (Special K)
Used legally as an animal tranquilizer
– Often called a “club drug” along with MDMA, GHB,
rohypnol, LSD, PCP and methamphetamine
Special K causes delirium, amnesia, depression and
long term memory difficulty
Chapter 7
Depressants
Ethyl alcohol is a common depressant and alcohol is
a $40 billion industry in America
Barbiturates – commonly known as downers are
highly addictive and with-drawl is difficult and
dangerous.
– Most often barbiturates are prescribed to reduce
anxiety and help the user sleep.
Chapter 7
Ethyl Alcohol
Most common drug toxicologist requested to test for is
alcohol
Types of alcohol:
– Ethanol – drinking alcohol
– Methanol – wood alcohol, used as solvent in
chemistry and to thin out paint
– Isopropanol – rubbing alcohol
Chapter 7
Alcohol—Ethyl Alcohol (C2H5OH)
Most abused drug in America
About 40 percent of all traffic deaths are alcohol-related
Toxic—affecting the central nervous system, especially the brain
Colorless liquid, generally diluted in water
Acts as a depressant
Alcohol appears in blood within minutes of consumption; 30–90 minutes for full
absorption
Detoxification—about 90 percent in the liver
Chapter 7
50
About 5 percent is excreted unchanged in breath, perspiration, and urine
The Fate of Alcohol in the Body
• Passes from mouth, through the esophagus, into
the stomach and then to the small intestines at
which point it is absorbed into the blood
• Within minutes of absorption it is distributed by the
circulatory system to all parts of the body
•
•
•
•
Chapter 7
Liver
Kidneys
Brain
Lungs
The Fate of Alcohol in the Body
Chapter 7
Effects of Alcohol
• CNS Depressant
– Studies conducted over the years demonstrate the relationship
between blood alcohol concentrations and effects on the brain
Blood Alcohol
Concentration
(g/dL)
Clinical Signs/Symptoms
0.01-0.05
Apparent stimulation – depression of inhibitory processes
0.03-0.12
Affects judgment and control, sensory-motor impairment
0.09-0.25
Reduced vision, impaired balance, drowsiness
0.18-0.30
Disorientation, loss of critical judgment, increased pain threshold,
increased muscle uncoordination, slurred speech
0.25-0.40
Vomiting, limited response to stimuli, inability to stand or walk
0.35-0.50
Coma
0.45+
Death
Chapter 7
53
Widmark Curve
The LD50 of
ethanol in rats is
10.3 g/kg.
Chapter 7
Rate of Absorption
Depends on:
Amount of alcohol consumed
The alcohol content of
the beverage
Time taken to consume it
Quantity and type of food
present in the stomach
Physiology of the consumer
55
Chapter 7
BAC Calculation
Burn-off rate of 0.015 percent per hour, but can vary:
Male
BAC = 0.071  (oz)  (% alcohol)
body weight
% alcohol refers to the proof,
for example; 80 proof = 40 %
alcohol content.
Female
BAC = 0.085  (oz)  (% alcohol)
body weight
Ounces (oz) refers to the
amount of alcohol not the
total volume of the drink
56
Chapter 7
BAC: Blood Alcohol Content
Expressed as percent weight per
volume of blood
Legal limit in all states is 0.08
percent
Parameters influencing BAC:
• Body weight
• Alcohol content
• Number of beverages consumed
• Time since consumption
57
Chapter 7
Generalizations
During absorption, the concentration of alcohol in arterial blood is higher
than in venous blood.
Breath tests reflect alcohol concentration in the pulmonary artery.
The breathalyzer also can react with acetone, acetaldehyde, methanol,
isopropyl alcohol, and paraldehyde, but these are toxic and their
presence means the person is in serious medical condition.
Breathalyzers now use an infrared light-absorption device with a digital
readout. Prints out a card for a permanent record.
58
Chapter 7
Alcohol content of typical drinks
• The table below shows the alcohol content in a typical drink.
A drink with a 40% alcohol content is called 80-proof (liquor).
The table clearly shows that a typical serving of beer, wine or
liquor will contain the same alcohol content.
5 ounces of wine
24 proof
24 ÷ 2 = 12 (% alcohol)
12 ÷ 100 = 0.12
0.12 x 5 oz
=
0.6 ounces ethanol
Chapter 7
12 ounces of beer
10 proof
10 ÷ 2 = 5 (% alcohol)
5 ÷ 100 = 0.05
0.05 x 12 oz
=
0.6 ounces ethanol
1 1/2 shot
vodka
80 proof
80 ÷ 2 = 40 (% alcohol)
40 ÷ 100 = 0.4
0.4 x 1.5 oz
=
0.6 ounces ethanol
The Breathalyzer
Collects and measures alcohol content
of alveolar breath
Breath sample mixes with 3 ml of 0.025 percent K2Cr2O7 in sulfuric acid
and water:
2K2Cr2O7 +3C2H5OH + 8H2SO4  2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11H2O
Potassium dichromate is yellow; as concentration decreases, its light
absorption diminishes,
So the breathalyzer measures alcohol concentration by measuring light
absorption of potassium dichromate
60
Chapter 7
Henry’s Law
When a volatile chemical is dissolved in a liquid and is brought to
equilibrium with air, there is a fixed ratio between the concentration of
the volatile compound in the air and its concentration in the liquid
THEREFORE, the concentration of alcohol in breath is proportional
to that in the blood.
This ratio of alcohol in the blood to alcohol in the alveolar air is
approximately 2,100 to 1.
1 ml of blood will contain nearly the same amount of alcohol as
2,100 ml of breath.
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Chapter 7
Pennsylvania DUI Guidelines
• Blood Alcohol Content (BAC) of .08 to .099
– 6 month maximum probation and a $300.00 fine
• BAC of .10 to .159
– mandatory 48 hour imprisonment, up to 6 months
maximum probation, a $500.00 to $5,000.00 fine, and 12
month license suspension
• BAC of .16 or higher, or if you refuse to give a blood
or breath sample
– mandatory 72 hour imprisonment, up to 6 months
maximum probation, a $1,000.00 to $5,000.00 fine and
12 month license suspension
Chapter 7
Hemlock
Chapter 7
• Chemical structure similar to
nicotine
• Naturally grows in
temperate climates and
have been introduced to the
U.S. where it is considered
an invasive species in 12
states growing along the
sides of high ways
• Hemlock is a neurotoxin and
disrupts the central nervous
system
• Socrates drank a solution of
hemolock instead of facing
his lesser punishment for
corruption of the minds of
the youth
Belladonna
•
•
•
Chapter 7
One of the most toxic plants found
in the Western Hemisphere. The
berries pose the greatest danger to
children because they look
attractive and have a somewhat
sweet taste. The consumption of
two to five berries by children and
ten to twenty berries by adults can
be lethal.
Belladonna literally means beautiful
lady in Italian
Women used to place drops in their
eyes for cosmetic purposes to
dilate their pupils which was a sign
of beauty
Arsenic and the Marsh Test
Chapter 7
• Marie Lafarge was charged
with killing her husband in
1840 after eating a slice of
cake.
• The maid swore she saw
Marie adding a white
powder to his drink
• Arsenic oxide is rat poison
and she said she was
buying it for her husbands
forge
• The marsh test developed
by James Marsh tested
positive when preformed on
her husband body . Mathieu
Orfila was an expert witness
on this case
No trace left behind
• If left no trace the
previously
discussed poisons
are easy to obtain
and the symptoms
look like death by
natural causes.
There are many,
many more.
Chapter 7
In 1814 Mathieu Orfila published Traite
des poisons,
the first systematic approach to the
study of the chemistry of poisons
Dioxin & the Ukrainian President
Race
• In Dec 2004, doctors
confirmed that Viktor
Yushchenko the
Ukrainian presidential
candidate running
against the old-line
Russian establishment
was suffering from
dioxin poisoning
• Dioxin is fat soluble
and is more of a
chronic poisoning than
acute
Chapter 7
Polonium – 210 & International
Espionage
•
•
•
Chapter 7
Aleksandr Litvinenko was a
former lieutenant colonel in the
Russian secret service, the
KGB who became a vocal critic
of the Russian government.
On Nov. 1, 2006 he fell ill after
the ingestion of polonium 210 a
rare and highly radioactive
isotope.
Investigations link that
Litvinenko was meeting with 2
former KGB officers that same
day. Traces of polonium 210
were found in the areas that
Aleksandr wasbut anyone that
could have been connected
with the crime as since
disappeared.
Ricin & Georgi Markov
•
•
•
•
Chapter 7
Bulgarian secret police
assassinated Georgi Markov in
Sept. 1978.
Markov was from Bulgaria but
now resided in London where
he broadcasted publicily
against the Bulgarian regime.
As Markov was waiting for the
bus he felt a sharp jab in his
right thigh. He turned to see a
man with an umbrella behind
him who promptly apologized
Markov thought nothing of it
and was admitted to the
hospital the next day with a
high fever & vomiting and then
died within 3 days
Lead Poisoning
•
•
•
•
•
Chapter 7
Lead compounds are not highly
poisonous, but chronic
exposure to lead poses a real
health problem for many
Americans
Exposure can lead to subtle
brain damage, affecting
memory and thought processes
Most common method of
exposure is lead based paints
banned in 1978
In 1995 there was a ban on
leaded gasoline but still tons
remain in our soil
In 1986 there was a nation
wide ban on lead pipe in homes