Download Chapter 7 - Westford Academy Forensics

Chapter 7
Drug Evidence
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
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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
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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
*Living subjects
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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
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
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Confirmatory tests
 Spectrophotometry
 Ultraviolet (UV)
 Visible
 Infrared (IR)
 Mass spectrometry
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Presumptive Color Tests
 Marquis—turns purple in the
presence of most opium
derivatives and orange-brown
with amphetamines
 Dillie-Koppanyi—turns violetblue 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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Spot Testing: OTC Drug ID
 Indicators – chemicals that react with
substances in a specific way, based on
the properties of the substances, giving
a characteristic color change result
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Solubility in water
Universal indicator
Hydrochloric acid
Ferric nitrate
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Solubility in Water
 Some substances
are water soluble
and will dissolve
into water
 Alka-seltzer,
sodium bicarbonate
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 Other substances
are not water
soluble and will
clump when mixed
with water
 Acetaminophen,
Aspirin, Excedrin
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Universal Indicator
 Universal indicator will tell you the pH
of a solution, by the color it turns
red
orange yellow green
blue
violet
 Aspirin & Excedrin are acidic
 Tylenol is neutral
 Alka-seltzer & sodium bicarb are basic
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Hydrochloric Acid
 Some substances will react with HCl to
generate a gas, producing bubbles
 Alka-seltzer and
sodium bicarb
will bubble
 Acetaminophen,
Aspirin, and
Excedrin won’t
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Ferric Nitrate
 Ferric nitrate has an orange color, but it
will react with Aspirin to turn purple
 Drugs that contain
Aspirin: Excedrin
& Alka-seltzer
 No Aspirin in
Tylenol or sodium
bicarbonate
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