1. 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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Drugs
Students will learn:
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.
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Drugs
Students 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.
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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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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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6. 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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7. 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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8. Identification of Drugs
PDR—Physicians’ Desk Reference
Field Tests—presumptive tests
Laboratory Tests—conclusive tests
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9. 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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10. 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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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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12. 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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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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14. Types of Chromatography
Paper
Thin Layer (TLC)
Gas (GC)
Pyrolysis Gas (PGC)
Liquid (LC)
High Pressure Liquid (HPLC)
Column
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Paper Chromatography
Stationary phase—paper
Mobile phase—a liquid solvent
Capillary action moves the mobile phase through the stationary phase
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16. 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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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).
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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 Rf for the qualitative analysis
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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).
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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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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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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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Mass Spectrometry
Gas chromatography has one major drawback, it does not give a specific identification. Mass spectrometry cannot separate mixtures or provide specific identification. By combining the two (GCMS), constituents of mixtures can be specifically identified.
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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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Mass Spectra
Each molecular species has its own unique mass spectrum.
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26. 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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27. 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 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.
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28. People of Historical Significance
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.
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