1. FORENSIC SCIENCE Toxicology

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

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

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

5. 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

6. 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

7. 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

8. 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

9. 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.

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

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

12. 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

13. 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)

14. 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

15. 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

16. 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.

17. 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.

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

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

20. 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.

21. 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

22. 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

23. 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.

24. Alcohol in the Circulatory System
Forensic Science
Toxicology Unit

25. 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

26. 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

27. 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

29. 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

30. 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 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!

32. 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

34. 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

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

36. 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

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

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