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FORENSIC SCIENCEToxicology

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Toxicology Study of poisons or the detection of foreign

substances in the body that can have a toxic effect such as:• Alcohol• Industrial chemicals• Poisonous gas• Illegal drugs• Drug overdoses

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TOXICOLOGYTYPES:

• Environmental--air, water, soil

• Consumer--foods, cosmetics, drugs

• Medical, clinical, forensic

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Forensic Toxicology Postmortem--medical examiner or coroner Criminal--motor vehicle accidents (MVA),

assault, etc. Workplace drug testing Sports--human and animal

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Why do Toxicology?Toxicology can:

• Be a cause of death

• Contribute to death

• Cause impairment

• Explain behavior

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OUR STUDY

Drugs Poisons Alcohol

Basically, toxicology involves the separation, detection, identification and measurement of the drug and/or poison.

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Drugs and Crime Definition--a natural or synthetic substance designed

to affect the subject psychologically or physiologically.

“Controlled substances”--drugs that are restricted by law

Controlled Substances Act--enacted in 1970 lists illegal drugs, their category and their penalty for possession, sale or use.

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Testing

PDR’s--Physician’s Desk Reference Field Tests--presumptive tests Lab Tests--conclusive tests

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PDR’s

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Analysis of Drugs

Controlled Substances Act

• Schedule I--heroin, LSD

• Schedule II--morphine, methadone

• Schedule III--barbiturates, amphetamines

• Schedule IV--other stimulates and depressants

• Schedule V--codeine

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DRUG IDENTIFICATIONScreening tests or

presumptive tests Color tests Microcrystalline test--

a reagent is added that produces a crystalline precipitate which are unique for certain drugs.

Confirmation tests Chromatography Spectrophotometry Mass spectrometry

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Presumptive Color Tests

Marquis--turns purple in the presence of most opium derivatives and orange-brown with amphetamines

Dillie-Koppanyi--turns violet-blue in the presence of barbiturates

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Presumptive Color Tests Duquenois-Levine--turns a purple color in

the presence of marijuana Van Urk--turns a blue-purple in the

presence of LSD Scott test--color test for cocaine

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Confirmation TestsChromatography

Techniques for separating mixtures into their component compounds

Includes two phases--one mobile and one stationary that flow past one another

As the mixture separates it interacts with the two phases.

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Types of Chromatography Paper Thin Layer Gas Pyrolysis Gas High Pressure Liquid (HPLC)

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Paper Chromatography

Stationary phase--paper

Mobile phase--a liquid solvent

Capillary action moves the mobile phase through the stationary phase

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Thin Layer Chromatography Stationary phase--a

thin layer of coating on a sheet of plastic or glass (usually aluminum or silica)

Mobile phase--a liquid solvent

from www.lbp.police.uk

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Retention Factor (Rf) This is a number that

represents how far a compound travels in a particular solvent

It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.

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Retention Factor (Rf)

If the Rf value for an unknown compound is close to or the same as that for the known compound, the two compounds are most likely similar or identical (a match)

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Results from Thin Layer

What was in the unknown sample?

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Gas Chromatography

Stationary phase--a solid or very syrupy liquid lines a tube or column

Mobile phase--an inert gas like nitrogen or helium

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GC Analysis Shows a peak that is proportional to the

quantity of the substance present Uses retention time instead of Rf for the

quantitative analysis

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Retention Time Time between the sample being injected

and when it exits the column reaching the detector.

Tm is the time taken for the mobile phase to pass through the column

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Pyrolysis Gas Chromatography

Used when a sample does not readily dissolve in a solvent

If heating this sample decomposes it into gaseous products, these products can be analyzed by CGC

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A pyrogram is a visual representation of the results

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High Pressure LiquidChromatography

Stationary phase--fine solid particles Mobile phase--a liquid solvent

A solvent is pumped through the column as a sample is injected into it. The sample, as it moves, is slowed to differing degrees, depending on its interaction with the stationary phase. Different components of the sample mixture are, therefore, separated.

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Liquid Chromatography

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Mass Spectrometry

Gas chromatography has one major drawback--it does not give a specific identification. By teaming a gas chromatograph with a mass spectrometer, this is accomplished.

The mixture is separated first in a gas chromatograph. The GC column is directly attached to the mass spectrometer where a beam of electrons is shot through the sample molecules.

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MS (cont.)

The electrons cause the molecules to lose electrons and become positively charged. These are unstable and decompose into many smaller fragments. These fragments pass through an electric or magnetic field and are separated according to their masses.

NO TWO SUBSTANCES PRODUCE THE SAME FRAGMENTATION PATTERN.

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Example of a GS/MS

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Human Analysisfor Drugs

Blood

Urine

Vitreous

Bile

Liver tissue

Brain tissue

Kidney tissue

Spleen tissue

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“If all those buried in our cemeteries who were poisoned could raise their hands, we would probably be shocked by the numbers. --John Trestrail

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POISONERS in HISTORY 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.

Symptoms of VariousTypes of Poisoning

Type of Poison Symptom/Evidence• Caustic Poison (lye) Characteristic burns around the lips

and mouth of the victim

• Carbon Monoxide Red or pink patches on the chest and thighs. Unusually brighter red lividity

• Sulfuric acid Black vomit

• Hydrochloric acid Greenish-brown vomit

• Nitric acid Yellow vomit

• Phosphorous Coffee brown vomit. Onion or garlic odor

• Cyanide Burnt almond odor

• Arsenic, Mercury Pronounced diarrhea

• Methyl (wood) or Nausea and vomiting,

Isopropyl (rubbing) alcohol unconsciousness, possibly blindness

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Points to Know about aPoison

Form Common color Characteristic odor Solubility Taste Common sources Lethal dose Mechanism Possible methods of

administration Time interval of onset of

symptoms.

Symptoms resulting from an acute exposure

Symptoms resulting from chronic exposure

Disease states mimicked by poisoning

Notes relating to the victim Specimens from victim Analytical detection methods Known toxic levels Notes pertinent to analysis of

poison List of cases in which poison

was used

from “Criminal Poisoning” by John Trestrail

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New Terror--YuschenkoIn 2004, Viktor Yushchenko

announced independent candidate for president of the Ukraine. His major rival was Prime Minister Viktor Yanukovych. The campaign was often bitter, controversial, and violent, with accusations of "dirty tricks" from both sides. Yushchenko became seriously ill in early September 2004. On December 11, Austrian doctors confirmed Yushchenko was poisoned with TCDD dioxin having had more than 1,000 times the usual concentration in his body. This is the second highest dioxin level ever measured in a human. No one has ever been tried for this crime.

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Evidence

ClassPresumptive or screening tests can be used to

determine that it is a drug.

IndividualChromatography, especially in conjunction with

mass spectrometry, will specifically identify a drug or poison and its components.

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Toxicology

of Alcohol

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Statistics• Nearly 17,500 automobile deaths in the U.S. • 40% of all auto fatalities are due to alcohol• Over 2 million people/year injured, requiring

hospitalization due to alcohol• Most abused drug; Must be able to test

rapidly/accurately, due to legal needs

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Alcohol--Ethyl Alcohol: C2H5OH

Toxic--affecting the central nervous system, especially the brain

Toxicologists can test for alcohol in body fluids, tissues, organs Acts as a depressant Alcohol appears in blood within minutes of

consumption; 30-90 minutes for full absorption Detoxification--about 90% in the liver About 5% is excreted unchanged in breath, perspiration

and urine

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Effects of Increasing Blood Alcohol

.02 MELLOW FEELING. SLIGHT BODY WARMTH. LESS INHIBITED.

.05 NOTICEABLE RELAXATION. LESS ALERT. LESS SELF-FOCUSED. COORDINATION IMPAIRMENT BEGINS.

.08 DRUNK DRIVING LIMIT. DEFINITE IMPAIRMENT IN COORDINATION AND JUDGMENT.

.10 NOISY. POSSIBLE EMBARRASSING BEHAVIOR. MOOD SWINGS. REDUCTION IN REACTION TIME.

.15 IMPAIRED BALANCE AND MOVEMENT. CLEARLY DRUNK.

.30 MANY LOSE CONSCIOUSNESS

.40 MOST LOSE CONSCIOUSNESS; SOME DIE.

.50 BREATHING STOPS. MANY DIE.

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Rate of AbsorptionDepends 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

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BACBlood Alcohol Content

Expressed as percent weight per volume Legal limits in most states is 0.08% Parameters influencing BAC:

• Body weight• Alcoholic content• Number of beverages consumed• Time between consumption

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BAC Burn off rate if 0.015% per hour but can vary

• MaleBAC male = 0.071 x (oz) x (% alcohol)

body weight• FemaleBAC female = 0.085 x (oz) x (% alcohol)

body weight

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Dose-Response CurveThis is a dose-response curve

for ethyl alcohol, the kind of alcohol in alcoholic beverages. At low doses the effects of alcohol are familiar and are not life-threatening, but may still be very dangerous. At higher doses, alcohol is extremely toxic to humans and can cause death.

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Field Tests

Preliminary tests--used to determine the degree of suspect’s physical impairment and whether or not another test is justified.

Psychophysical tests--3 Basic Tests• Horizontal gaze nystagmus

(HGN)--follow a pen or small flashlight, tracking left to right with one’s eyes. In general, wavering at 45 degrees indicates 0.10 BAC.

• Nine Step walk and turn (WAT): comprehend and execute two or more simple instructions at one time.

• One-leg stand (OLS): maintain balance, comprehend andexecute two or more simple instructions at one time.

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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, and this ratio is constant for a given

temperature. 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 2100

to 1. In other words 1 ml of blood will contain nearly the same amount of alcohol as 2100 ml of breath.

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The Breathalyzer more practical in the field collects and measures alcohol content of alveolar

breath Breath sample mixes with 3 ml of 0.025 %

K2Cr2O7 and 0.025 % silver nitrate in sulfuric acid and water2K2Cr2O7 + 3C 2H5H + 8H 2SO4 2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11 H2O

Potassium dichromate is yellow, as concentration decreases the light absorption diminishes so the breathalyzer indirectly measures alcohol concentration by measuring light absorption of potassium dichromate before and after the reaction with alcohol

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Generalizations During absorption, the concentration of alcohol in

arterial blood will be higher than in venous blood. Breath test reflects alcohol concentration in the

pulmonary artery. Breathalyzer also can react with acetone (as found with

diabetics), acetaldehyde, methanol, isopropyl alcohol, and paraldehyde, but these are toxic and their presence means the person is in serious medical condition.

Now using an infrared light absorption device with a digital read-out. Prints out a card for a permanent record.

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REALLYREALLY

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