Standard

1. Standard • 15) Evaluate a death related to chemicals that can be harmful or poisonous to the human body, such as drugs or carbon monoxide. Describe the process for collecting and preserving toxicology evidence and the techniques used for detecting the type of substance

2. Chapter 9 – Drugs “Having sniffed the dead man’s lips, I detected a slightly sour smell, and I came to the conclusion that he had poison forced upon him.” – Sherlock Holmes, in Sir Arthur Conan Doyle’s “A Study in Scarlet”

3. Drugs and Crime • Drug – 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.

4. Controlled Substances Act • Schedule I – high potential for abuse; no currently acceptable medical use in the U.S.; a lack of accepted safety for use under medical supervision • Schedule II – high potential for abuse; a currently accepted medical use with severe restrictions; abuse may lead to severe psychological or physical dependence • Schedule III – lower potential for abuse than the drugs in I or II; a currently accepted medical use in treatment in the U.S.; abuse may lead to moderate physical dependence or high psychological dependence • Schedule IV – low potential for abuse relative to drugs in III; a currently accepted medical use in treatment in the U.S.; abuse may lead to limited physical dependence or psychological dependence relative to drugs in III • Schedule V – low potential for abuse relative to drugs in IV; currently accepted medical use in treatment in the U.S.; abuse may lead to limited physical dependence or psychological dependence relative to drugs in IV

5. Examples of Controlled Substance and their Schedule Placement • Schedule I – heroin (Diacetylmorphine), LSD, marijuana, ecstasy (MDMA) • Schedule II – cocaine, morphine, amphetamines (including methamphetamines), PCP, Ritalin • Schedule III – Intermediate acting barbiturates, anabolic steroids, ketamine • Schedule IV – other stimulates and depressants including Valium, Xanan, librium, phenobarbital, Darvon • Schedule V – codeine found in low doses in cough medicines.

6. “Testing” for Drugs • PDR’s – Physician’s Desk Reference • Field Tests – presumptive tests • Lab Tests – conclusive tests

7. Blood Urine Hair Gastric Contents Bile Liver tissue Brain tissue Kidney tissue Spleen tissue Vitreous Humor of the Eye Human Componentsfor Drug Analysis

8. Physician Desk Reference • PDR – a physician’s desk reference is used to identify manufactured pills, tablets and capsules. It is updated each year. This can sometimes be a quick and easier identifier of the legally made drugs that may be found at a scene. The reference book gives a picture of the drug, whether it is a prescription, over the counter, or a controlled substance; as well as, more detailed information about the drug.

9. PDR Key

10. Screening tests or presumptive tests Spot or color tests Microcrystalline test – a reagent is added that produces a crystalline precipitate which are unique for certain drugs. Chromatography Confirmatory tests Spectrophotometry Ultraviolet (UV) Visible Infrared (IR) Mass spectrometry Drug Identification

11. 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 • 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

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

13. Chromatography • Technique 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

14. Paper Chromatography • Stationary phase – paper • Mobile phase – a liquid solvent Capillary action moves the mobile phase through the stationary phase

15. 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

16. 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 • 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)

17. Phases Stationary – a solid or very syrupy liquid lines a tube or column Mobile – an inert gas like nitrogen or helium Analysis Shows a peak that is proportional to the quantity of the substance present Uses retention time instead of Rf for the quantitative analysis Gas Chromatography

18. Retention Time (Rt) • Time it takes a compound to travel from the injection port to the detector. • RRt – relative retention time is the ratio of the retention time of the substance to the retention time of a standard that is placed into the sample. It is considered more reliable.

19. Uses of Gas Chromatography • Not considered a confirmation of a controlled substance • Used as a separation tool for mass spectroscopy (MS) and infrared spectroscopy (IR) • Used to quantitatively measure the concentration of a sample (In a courtroom, there is no real requirement to know the concentration of a substance. It does not affect guilt or innocence)

20. 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

21. High Pressure Liquid Chromatography • 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.

22. Spectrophotometry Spectroscopy – the interaction of electromagnetic radiation with matter Spectrophotometer – An instrument used to measure and record the absorption spectrum of a chemical substance

23. Spectrophotometry Components • A radiation source • A frequency selector • A sample holder • A detector to convert electromagnetic radiation into an electrical signal • A recorder to produce a record of the signal Types • Ultraviolet • Visible • Infrared

24. Infrared Spectometry • Material absorbs energy in the near-IR region of the electromagnetic spectrum • Compare the IR light beam before and after passing through a transparent sample • Result – an absorption spectrum • Gives a unique view of the substance – like a fingerprint

25. 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.

26. Mass Spectrometry (continued) 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. 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 that sorts them according to their mass-to-charge ratio. NO TWO SUBSTANCES PRODUCE THE SAME FRAGMENTATION PATTERN.

27. Mass Spectrum Each molecular species has its own unique mass spectrum

28. IR Spectrophotometry andMass Spectrometry • Both work well in identifying pure substances • Mixtures are difficult to identify in both techniques • Both are compared to a catalog of knowns

29. People of Historical Significance Arthur Jeffrey Dempster was born in Canada, but studied and received his PhD from the University of Chicago. He began teaching physics there in 1916. In 1918, Dempster developed the first modern mass spectrometer. His version was over 100 times more accurate than previous ones developed, and established the basic theory and design of mass spectrometers that is still used to this day.

30. People of Historical Significance Francis William Aston was a British physicist who won the Nobel Prize in Chemistry for his work in the invention of the mass spectrometer. He used a method of electromagnetic focusing to invent the mass spectrograph. This allowed him to identify no fewer than 212 of the 287 naturally occurring isotopes.