1 FORENSIC SCIENCE Toxicology

2 TOXICOLOGY TYPES: Environmental--air, wter, soil Consumer--foods, cosmetics, drugs Medical, clinical, forensic

3 Forensic Toxicology u Postmortem--medical examiner or coroner u Criminal--motor vehicle accidents (MVA), assult, etc. u Workplace drug testing u Sports--human and animal

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

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

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

7 PDR’s

8 Analysis of Drugs u Controlled Substances Act Schedule I--heroin, LSD Schedule II--morphine, methadone Schedule III--barbiturates, amphetamines Schedule IV--other stimulates and depressants Schedule V--codeine

9 DRUG IDENTIFICATION Screening tests or presumptive tests u Color tests u Microcrystalline test-- a reagent is added that produces a crystalline precipitate which are unique for certain drugs. Confirmation tests u Chromatography u Spectrophotometry u Mass spectrometry

10 Presumptive Color Tests u Marquis--turns purple in the presence of most opium derivatives and orange-brown with amphetamines u Dillie-Koppanyi--turns violet-blue in the presence of barbiturates

11 Presumptive Color Tests u Duquenois-Levine--turns a purple color in the presence of marijuana u Van Urk--turns a blue-purple in the presence of LSD u Scott test--color test for cocaine

12 Confirmation Tests Chromatograhy u Techniques for separating mixtures into their component compounds u Includes two phases--one mobile and one stationary that flow past one another u As the mixture separates it interacts with the two phases.

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

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

15 Thin Layer Chromatography u Stationary phase--a thin layer of coating on a sheet of plastic or glass (usually aluminum or silica) u Mobile phase--a liquid solvent

16 Retention Factor (R f ) u This is a number that represents how far a compound travels in a particular solvent u It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.

17 Retention Factor (R f ) If the R f 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)

18 Gas Chromatography u Stationary phase--a solid or very syrupy liquid lines a tube or column u Mobile phase--an inert gas like nitrogen or helium

19 GC Analysis u Shows a peak that is proportional to the quantity of the substance present u Uses retention time instead of Rf for the quantitative analysis

20 Retention Time u Time between the sample being injected and when it exits the column reaching the detector. u Tm is the time taken for the mobile phase to pass through the column

21 Pyrolysis Gas Chromatography u Used when a sample does not readily dissolve in a solvent u If heating this sample decomposes it into gaseous products, these products can be analyzed by CGC u A pyrogram is the visual representation of the results

22 High Pressure Liquid Chromatography u Stationary phase--fine solid particles u 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 tits interaction with the stationary phase. Different components of the sample mixture are, therefore, separated.

23 Mass Spectrometry Gas chromatography has one major drawback--it does 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.

24 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.

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 MonoxideRed or pink patches on the chest and thighs. Unusually brighter red lividity Sulfuric acidBlack vomit Hydrochloric acidGreenish-brown vomit Nitric acidYellow vomit PhosphorousCoffee brown vomit. Onion or garlic odor CyanideBurnt almond odor Arsenic, MercuryPronounced diarrhea Methyl (wood) orNausea and vomiting, Isopropyl (rubbing) alcohol unconsciousness, possibly blindness

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

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