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Chapter 7 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
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Chapter 7 Kendall/Hunt Publishing Company2 Drugs 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. Students will learn:
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Chapter 7 Kendall/Hunt Publishing Company3 Drugs 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. Students will be able to:
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Chapter 7 Kendall/Hunt Publishing Company4 Drugs 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.
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Chapter 7 Kendall/Hunt Publishing Company5 Drugs and Crime 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 Controlled Substances Act is a law that was enacted in 1970; it lists illegal drugs, their category and their penalty for possession, sale or use.
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Chapter 7 Kendall/Hunt Publishing Company6 Controlled Substances Act Schedule I—high potential for abuse; no currently acceptable medical use in the US; 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 the US; 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 the US; abuse may lead to limited physical or psychological dependence relative to drugs in III Schedule V—low potential for abuse relative to drugs in IV; currently accepted medical use in the US; abuse may lead to limited physical or psychological dependence relative to drugs in IV
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Chapter 7 Kendall/Hunt Publishing Company7 Examples of Controlled Substances 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 stimulants and depressants including Valium, Xanan, Librium, phenobarbital, Darvon Schedule V—codeine found in low doses in cough medicines
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Chapter 7 Kendall/Hunt Publishing Company8 Identification of Drugs PDR—Physicians’ Desk Reference Field Tests—presumptive tests Laboratory Tests—conclusive tests
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Chapter 7 Kendall/Hunt Publishing Company9 Human Components Used for Drug Analysis Blood Urine Hair Gastric Contents Bile Liver tissue Brain tissue Kidney tissue Spleen tissue Vitreous Humor of the Eye
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Chapter 7 Kendall/Hunt Publishing Company10 Physicians’ Desk Reference 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, whether it is a prescription, over the counter, or a controlled substance; as well as more detailed information about the drug.
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Chapter 7 Kendall/Hunt Publishing Company11 Drug Identification Screening or presumptive tests Spot or color tests Microcrystalline test— a reagent is added that produces a crystalline precipitate which is unique for a certain drug. Chromatography Confirmatory tests Spectrophotometry Ultraviolet (UV) Visible Infrared (IR) Mass spectrometry
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Chapter 7 Kendall/Hunt Publishing Company12 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, blue
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Chapter 7 Kendall/Hunt Publishing Company13 Chromatography 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.
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Chapter 7 Kendall/Hunt Publishing Company14 Types of Chromatography Paper Thin Layer (TLC) Gas (GC) Pyrolysis Gas (PGC) Liquid (LC) High Pressure Liquid (HPLC) Column
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Chapter 7 Kendall/Hunt Publishing Company15 Paper Chromatography Stationary phase— paper Mobile phase—a liquid solvent Capillary action moves the mobile phase through the stationary phase
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Chapter 7 Kendall/Hunt Publishing Company16 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
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Chapter 7 Kendall/Hunt Publishing Company17 Retention Factor (R f ) 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 R f 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).
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Chapter 7 Kendall/Hunt Publishing Company18 Gas Chromatography 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 R f for the qualitative analysis
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Chapter 7 Kendall/Hunt Publishing Company19 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).
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Chapter 7 N. Ron Leigh Case While sitting quietly at his desk, N. Ron Leigh, an executive of a multinational energy company, was stricken with what appeared to be a severe allergic reaction. His throat swelled to such an extent that he could hardly breathe. Rapid and effective response to a 911 call saved his life. Both the paramedics and police wondered what brought on such a sudden attack.
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Chapter 7 N. Ron Leigh Case - Facts ®A bottle of Tylenol was found on Mr. Leigh’s desk ®It was well known that Leigh suffered from asthma, bouts of sinusitis, and tension headaches. ®Several caplets from the Tylenol bottle have been submitted to your lab for analysis ®Were they in fact Tylenol or aspirin or ibuprofen (either of the later two could have caused an allergic reaction)?
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Chapter 7 Lab Data – TLC Chromatography ®Ms. Scholle ran TLC of known Tylenol, aspirin, ibuprofen, and the pills found at the scene last night. ®The chromatogram was developed in class w/iodine pellets. ®Look at the resulting chromatogram and write down observations
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Chapter 7 ®Use the following data to calculate the Rf for each of the samples… Lab Data – TLC Chromatography
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Chapter 7 N. Ron Leigh Case ®A plasma sample taken from Mr. Leigh has been submitted to the lab for analysis. ®Did Mr. Leigh actually take aspirin? How much? ®Use handout and data to help you finish solving this mystery and write a summary report suitable for admission into a trial.
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Chapter 7 Kendall/Hunt Publishing Company25 Spectroscopy Spectroscopy—the interaction of electromagnetic radiation with matter. Spectrophotometer—an instrument used to measure and record the absorption spectrum of a chemical substance.
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Chapter 7 Kendall/Hunt Publishing Company26 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
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Chapter 7 Kendall/Hunt Publishing Company27 Infrared Spectometry Material absorbs energy in the near-IR region of the electromagnetic spectrum. Compares the IR light beam before and after passing through a transparent sample. Result—an absorption or transmittance spectrum Gives a unique view of the substance; like a fingerprint
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Chapter 7 Kendall/Hunt Publishing Company28 Mass Spectrometry Gas chromatography has one major drawback, it does not give a specific identification. Mass spectrometry cannot separate mixtures. By combining the two (GCMS), constituents of mixtures can be specifically identified.
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Chapter 7 Kendall/Hunt Publishing Company29 Mass Spectrometry 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 a magnetic field.
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Chapter 7 Kendall/Hunt Publishing Company30 Mass Spectra Each molecular species has its own unique mass spectrum.
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Chapter 7 Kendall/Hunt Publishing Company31 IR Spectrophotometry and Mass Spectrometry Both work well in identifying pure substances. Mixtures are difficult to identify in both techniques Both are compared to a catalog of knowns
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