Chapter 7 - Westford Academy Forensics
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Transcript 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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