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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
                                             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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            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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               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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            Identification of Drugs

             PDR—Physicians’ Desk Reference
             Field Tests—presumptive tests
             Laboratory Tests—conclusive
              tests



Chapter 7            Kendall/Hunt Publishing Company   7
             Human Components
            Used for Drug Analysis
             Blood                          Liver tissue
             Urine                          Brain tissue
             Hair                           Kidney tissue
             Gastric Contents               Spleen tissue
             Bile                           Vitreous Humor of
                                              the Eye



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              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                        Confirmatory tests
            presumptive tests                    Spectrophotometry
             Spot or color tests                   Ultraviolet (UV)
             Microcrystalline test—                Visible
              a reagent is added                    Infrared (IR)
              that produces a                    Mass spectrometry
              crystalline precipitate
              which is unique for a
              certain drug.
             Chromatography




Chapter 7                 Kendall/Hunt Publishing Company               10
            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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            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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              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



Chapter 7     Kendall/Hunt Publishing Company         15
                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).



Chapter 7                      Kendall/Hunt Publishing Company   16
            Gas Chromatography
            Phases                                 Analysis
             Stationary—a solid or a               Shows a peak that is
              viscous liquid that lines a            proportional to the
              tube or column                         quantity of the
             Mobile—an inert gas like               substance present
              nitrogen or helium                    Uses retention time
                                                     instead of Rf for the
                                                     qualitative analysis




Chapter 7                 Kendall/Hunt Publishing Company                17
                     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).


Chapter 7                Kendall/Hunt Publishing Company         18
                    Spectroscopy
             Spectroscopy—the interaction of
              electromagnetic radiation with matter.
             Spectrophotometer—an instrument used to
              measure and record the absorption spectrum of
              a chemical substance.




Chapter 7               Kendall/Hunt Publishing Company   19
              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. By
            combining the two (GCMS), constituents of
            mixtures can be specifically identified.




Chapter 7             Kendall/Hunt Publishing Company      22
            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.


Chapter 7           Kendall/Hunt Publishing Company   23
                Mass Spectra




            Each molecular species has its own
            unique mass spectrum.

Chapter 7           Kendall/Hunt Publishing Company   24
            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



Chapter 7             Kendall/Hunt Publishing Company   25
             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.




Chapter 7                Kendall/Hunt Publishing Company                26
            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.



Chapter 7             Kendall/Hunt Publishing Company       27

				
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