Drugs

1. Drugs

2. Objectives You will understand: How to apply deductive reasoning to a series of analytical data. The limitations of presumptive (screening) tests. The relationship between the electromagnetic spectrum and spectroscopic analysis. The dangers of using prescription drugs, controlled substances, over-the-counter medications, and illegal drugs.

3. Objectives, continued You will be able to: Chemically identify illicit drug types. Classify the types of illicit drugs and their negative effects. Discuss the federal penalties for possession and use of controlled substances. Explain the need for confirmatory tests.

4. Objectives, continued You will be able to: Describe IR, UV-VIS spectroscopy, and GC-MS. Present and interpret data with graphs. Use the Physicians’ Desk Reference (PDR) to identify pills. Use technology and mathematics to improve investigations and communications.

5. A drug is a natural or synthetic substance designed to affect the subject psychologically or physiologically. “Controlled substances” are drugs that are restricted by law. The Controlled Substances Act is a law that was enacted in 1970; it lists illegal drugs, their categories, and penalties for possession, sale, or use. Drugs and Crime

6. Schedule I—high potential for abuse; no currently accepted medical use in the U.S.; a lack of accepted safety for use under medical supervision Examples: heroin (diacetylmorphine), LSD, marijuana, ecstasy (MDMA) Controlled Substances Act Schedule II—high potential for abuse; a currently accepted medical use with severe restrictions; abuse may lead to severe psychological or physical dependence Examples: cocaine, morphine, amphetamines (including methamphetamines), PCP, Ritalin

7. Schedule III—lower potential for abuse than the drugs in I or II; a currently accepted medical use in the U.S.; abuse may lead to moderate physical dependence or high psychological dependence Examples: intermediate-acting barbiturates, anabolic steroids, ketamine Controlled Substances Act, continued Schedule IV—low potential for abuse relative to drugs in III; a currently accepted medical use in the U.S.; abuse may lead to limited physical or psychological dependence relative to drugs in III Examples: stimulants and depressants including Valium, Xanax, Librium, phenobarbital, Darvon

8. Schedule V—low potential for abuse relative to drugs in IV; currently accepted medical use in the U.S.; abuse may lead to limited physical or psychological dependence relative to drugs in IV Examples: codeine found in low doses in cough medicines Controlled Substances Act, continued

9. An illegal drug is a drug that is against the law to have, use, or distribute. An illicit drug is a legal drug used in an inappropriate or illegal way. Illegal or Illicit?

10. Blood Urine Hair Gastric contents Bile Liver tissue Brain tissue Kidney tissue Spleen tissue Vitreous humor of the eye Human Components Used for Drug Analysis

11. PDR—A Physicians’ Desk Reference is used to identify manufactured pills, tablets, and capsules. It is updated each year. This can sometimes be a quick and easy identifier of the legally made drugs that may be found at a scene. The reference book gives a picture of the drug and states whether it is prescription, over-the-counter, or a controlled substance; it gives more detailed information about the drug as well. Physicians’ Desk Reference

12. Screening or presumptive tests Spot or color tests Microcrystalline test— a reagent is added, producing a crystalline precipitate that is unique for a certain drug Chromatography Confirmatory tests Spectrophotometry Ultraviolet (UV) Visible Infrared (IR) Mass spectrometry Drug Identification

13. Screening or presumptive tests only tell that the drug is possibly present. Confirmatory tests tell that the drug is positively present. (Screening tests are easier, cheaper, and quicker to use.) Drug Identification, continued

14. Marquis—turns purple in the presence of most opium derivatives and orange-brown with amphetamines Dille-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; blue Presumptive Color Tests

15. A technique for separating mixtures into their components Includes two phases—a mobile one that flows past a stationary one The mixture interacts with the stationary phase and separates Chromatography

16. Paper Thin-layer (TLC) Gas (GC) Pyrolysis gas (PGC) Liquid (LC) High-performance liquid (HPLC) Column Types of Chromatography

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

18. Thin-layer Chromatography Stationary phase—a thin layer of coating (usually alumina or silica) on a sheet of plastic or glass Mobile phase—a liquid solvent

19. 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 likely similar or identical (a match).

20. Phases Stationary—a solid or a viscous liquid that 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 Rffor the qualitative analysis Gas Chromatography

21. 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.) Uses of Gas Chromatography

22. Confirmatory Tests: Spectroscopy Spectroscopy—the interaction of electromagnetic radiation with matter Spectrophotometer—an instrument used to measure and record the absorption spectrum of a chemical substance

23. 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 Spectrophotometry

24. Infrared Spectrometry Material absorbs energy in the near-IR region of the electromagnetic spectrum Compares the IR light beam before and after it passes through a transparent sample Result—an absorption or transmittance 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. Mass spectrometry cannot separate mixtures. By combining the two (GC-MS), constituents of mixtures can be specifically identified.

26. In a mass spectrometer, an electron beam is directed at sample molecules in a vacuum chamber. The electrons break apart the sample molecules into many positive-charged fragments. These are sorted and collected according to their mass-to-charge ratio by an oscillating electric or magnetic field. Mass Spectrometry, continued

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

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

29. People of Historical Significance Arthur Jeffrey Dempster was born in Canada, but studied at 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 and established the basic theory and design of mass spectrometers that is still used to this day.

30. People of Historical Significance, continued Francis William Aston was a British physicist who won the 1922 Nobel Prize in Chemistry for his work in the invention of the mass spectrograph. He used a method of electromagnetic focusing to separate substances. This enabled him to identify no fewer than 212 of the 287 naturally occurring elemental isotopes.