FORENSIC SCIENCE Toxicology

Why do Toxicology? Toxicology can: Be a cause of death Contribute to death Cause impairment Explain behavior

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

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

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

DRUG IDENTIFICATION Screening 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

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

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

Confirmation Tests Chromatography 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.

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

Paper Chromatography Stationary phase--paper Mobile phase--a liquid solvent Capillary action moves the mobile phase through the stationary phase

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

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)

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

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 A pyrogram is the visual representation of the results

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.

MS (cont.) NO TWO SUBSTANCES PRODUCE THE SAME FRAGMENTATION PATTERN. 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.

Human Analysis for Drugs Blood Urine Vitreous Bile Liver tissue Brain tissue Kidney tissue Spleen tissue

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

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 Various Types 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

Points to Know about a Poison 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

Evidence Class Individual Presumptive or screening tests can be used to determine that it is a drug. Individual Chromatography, especially in conjunction with mass spectrometry, will specifically identify a drug or poison and its components.

Alcohol in the Circulatory System Forensic Science Toxicology Unit

How to measure Alcohol ingested Two ways to measure alcohol in the blood: 1. Direct chemical analysis of blood 2. Measure alcohol content of the breath

Pathway of Blood 20% of alcohol ingested is absorbed thru stomach walls into the portal vein Remaining alcohol passes into the small intestine Once in the blood the alcohol goes to the liver and moves up to the heart Eventually, blood makes its way to the lungs

Alveoli 250 million in lungs, located at the terminal ends of bronchial tubes It is the surface of these alveolar sacs that blood flowing through the capillaries comes into contact with fresh oxygenated air in the sacs

Pathway cont. CO2, alcohol, or any other volatile substance will move from the capillaries into the air sacs to be exhaled Oxygen moves into the air sacs

Henry’s Law When a volatile liquid (alcohol) is dissolved in a liquid (blood) and is brought to equilibrium with air (alveolar breath) there is a fixed ratio between the concentration of the volatile compound (alcohol) in the air (alveolar breath) and its concentration in the liquid (blood) and this reaction is constant for a given temperature (34°C) The ratio of alcohol in the blood to alcohol in alveolar air is approx. 2100 to 1…..in other words 1 mL of blood will contain nearly the same amount of alcohol as 21 mL of alveolar breath…. Thus….. Henry’s Law becomes a basis for relating breath to blood alcohol concentration!

Breath Test Instruments The Breathalyzer – first developed in 1954 Collects and measures alcohol content of alveolar breath I t is a spectrophotometer that has been designed to measure the absorption of light passing thru the K2Cr2O7 (potassium dichromate) solution at a single wavelength

IR absorption and/or with fuel cell Alcohol present is captured in breath chamber a beam of infrared light is aimed through the chamber A filter is used to select a wavelength of IR light at which alcohol will absorb Information is processed by a microprocessor and the percent blood-alcohol concentration is displayed on a digital readout It is also printed on a card to produce a permanent record of the test results

Field Sobriety Testing Performed to ascertain the degree of the suspect’s physical impairment and whether or not an evidential test is justified.

Psychophysical tests Horizontal gaze nystagmus Refers to an involuntary jerking of the eyes as they move to the side When bac is 0.10 %the jerking will begin before the eyeball has moved 45 degrees to the side

Higher bac will cause jerking at smaller angles Barbituates/depressants can cause nystagmus

Walk & Turn; One-Leg Stand Tasks test the subject’s ability to comprehend and accomplish two or more simple instructions at one time