Chapter 7

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.

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Chapter 7

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)

• We will not be discussing medical marijuana, If you are interesting in this topic please research it on your own time.

Schedule II—high potential for abuse; a currently accepted medical use with severe restrictions; abuse may lead to severe psychological or physical dependence 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 intermediate acting barbiturates, anabolic steroids, ketamine

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Chapter 7

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

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Chapter 7

Identification of Drugs

PDR—Physicians’ Desk Reference

Field Tests—presumptive tests

Laboratory Tests—conclusive tests

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Chapter 7

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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Chapter 7

Human ComponentsUsed for Drug Analysis

Blood

Urine

Hair

Gastric Contents

Bile

Liver tissue

Brain tissue

Kidney tissue

Spleen tissue

Vitreous Humor of the Eye

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Most commonly used

Chapter 7

Drug Identification

Presumptive tests Color tests

Chromatography

Crystal tests – When a reagent is added to an unknown drug certain crystals will begin to form

Confirmatory tests Spectrophotometry

Ultraviolet (UV) Visible Infrared (IR)

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Chapter 7

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

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Chapter 7

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

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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

Confirmatory Tests: SpectroscopySpectroscopy—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

Function Groups and Absorptions

Functional Group Type of Absorption Absorption Information (cm-1)

Aklyl C – H stretch 2950 – 2850 (m or s)

AlkenylC – H stretch 3100 – 3010 (m)

C = C stretch 1680 – 1620 (v)

Alkynyl C – H stretch ~3300 (s)

C ≡ C stretch 2260 – 2100 (v)

Aromatic

C – H stretch ~3030 (v)

C – H bend 860 – 680 (s)

C = C bend 1700 – 1500 (m, m)

Alcohol/Phenol O – H stretch 3550 – 3200 (broad, s)

Carboxylic Acid 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)

Amide C = O stretch 1690 – 1630 (s)

N – H stretch 3700 – 3500 (m)

Chapter 7

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

• Be a cause of death• Contribute to death• Cause impairment• Explain behavior

Chapter 7

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 considerChemical 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 731

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

Chapter 732

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)

Chapter 733

Symptoms of Various Types of Poisoning

Symptom/EvidenceCharacteristic 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, unconsciousnesspossibly blindness

Type of PoisonCaustic poison (lye)

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 metal 763 Antimony chloride 525

Nicotine 53 Cupric chloride 584

Sodium cyanide 6.4

Chapter 735

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.

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 prescription is needed.

Chapter 7

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

“Black Tar” Heroin

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

Cocaine powder

Chapter 7

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

• Insensitivity to pain• Feelings of super strength• Rage• Memory loss • Paranoia

Chapter 7

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 751

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

About 5 percent is excreted unchanged in breath, perspiration, and urine

Chapter 7

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• Liver• Kidneys• Brain• Lungs

Chapter 7

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 54

Chapter 7

Widmark Curve

The LD50 of ethanol in rats is 10.3 g/kg.

Chapter 756

Rate of Absorption

Depends on:

Amount of alcohol consumed

The alcohol content ofthe beverage

Time taken to consume it

Quantity and type of food present in the stomach

Physiology of the consumer

Chapter 757

BAC Calculation

Male

BAC =

Female

BAC =

Burn-off rate of 0.015 percent per hour, but can vary:

0.071 (oz) (% alcohol)

body weight

0.085 (oz) (% alcohol)

body weight

% alcohol refers to the proof, for example; 80 proof = 40 % alcohol content.

Ounces (oz) refers to the amount of alcohol not the total volume of the drink

Chapter 758

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

Chapter 759

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.

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 wine24 proof

24 ÷ 2 = 12 (% alcohol) 12 ÷ 100 = 0.12

0.12 x 5 oz=

0.6 ounces ethanol

12 ounces of beer10 proof

10 ÷ 2 = 5 (% alcohol) 5 ÷ 100 = 0.05

0.05 x 12 oz=

0.6 ounces ethanol

1 1/2 shotvodka

80 proof 80 ÷ 2 = 40 (% alcohol)

40 ÷ 100 = 0.4 0.4 x 1.5 oz

=0.6 ounces ethanol

Chapter 761

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

Chapter 762

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.

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

• 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

Chapter 7

Belladonna

• 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

Chapter 7

Arsenic and the Marsh Test

• 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

Chapter 7

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.

In 1814 Mathieu Orfila published Traite des poisons, the first systematic approach to the study of the chemistry of poisons

Chapter 7

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

• 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.

Chapter 7

Ricin & Georgi Markov

• 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

Chapter 7

Lead Poisoning

• 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