Transcript forensic science - McEachern High School

FORENSIC SCIENCE
Toxicology
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Drug Assignments
 Today
is the last day for DRUG
ASSIGNMENTS
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Forensic Files, 4-8
 What
is the difference between stimulants
and hallucinogens?
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Today is the last day to turn in:
 All
drug notes (3- Intro, Drugs, Testing)
 2 drug labs: Drugs & Money- table 3, Spot
test- table 1)
 Spectrograph review
 Technology assignment: Mouse Party or
Drug Dosage Gizmo
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Forensic File #2
 You
have been asked to determine the
difference between aspirin (salicylic acid)
and tylenol, both of which are white
powders.
 What would you use to tell the difference?
Think back to the lab from yesterday (HCl,
water, FeCl, Universal indicator). What
would this tell you?
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Today’s assignments
 Alcohol
notes from blog
 BAC lab
 BAC calculations
 Start
Crime 360- Gilpin Court
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Forensic File #3
 What
would you use to tell the difference?
Think back to the lab from yesterday (HCl,
water, FeCl, Universal indicator). What
would this tell you?
 Use Universal Indicator- this will tell you
the difference between acids and bases…
aspirin is an ACID
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Project
 Two
or three people per group
 Case must involve DRUGS, POISONS,
ARSON
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Drug-Control Laws
 Controlled
substance act, Title II or the
Comprehensive Drug Abuse Prevention and
Control Act of 1970
 Legal foundation of the Government’s fight
against abuse of drugs and other substances
 A consolidation of numerous laws
regulating the manufacture and distribution
of narcotics, stimulants, depressants, &
hallucinogens
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Drug Identification
 The
challenge is that the unknown
substance may have one of a thousand or
more commonly encountered drugs and the
investigator may have only a limited supply
of the evidence to test
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Screening tests
 Primary
function is to eliminate some drugs
from consideration
 Also referred to as PRESUMPTIVE tests
since they don’t actually identify the
substance
 These include spot tests (color change test)
and microcrystalline test
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DRUG IDENTIFICATION
Screening tests or
presumptive tests
 Color tests
 Microcrystalline test-a reagent is added that
produces a crystalline
precipitate which are
unique for certain
drugs.
Confirmation tests
 Chromatography
 Spectrophotometry
 Mass spectrometry
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Presumptive Color Tests:
Spot tests
 Often
done on a spot plate or
in a test tube
 Normally destroys the sample
 No spot test is specific for a
particular drug, so a negative
test is a good indicator for
ruling something out
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Presumptive Tests for drugs
Test
Color change
Indicates the presence of
Marquis
Purple
In presence of most opium
derivatives
Orange-brown
In presence of amphetamines &
methamphetamines
Dillie-Koppanyi
Violet-blue
Most barbituates
Duquenois-Levine
Purple
Marijuana
Van Urk
Purple
Presence of LSD
Scott
Blue
Powdered cocaine
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Microscopic tests
 Morphology-
most commonly used with
plant matter such as marijuana
 Look for botanical features associated with
plant
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Microcrystalline test
 Involves
dissolving the sample in a suitable
solvent, filtering and adding a precipitating
agent to promote crystallization
 The size and shape of the crystals are highly
characteristic of the drug
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Chromatography
 Thin
layer or gas chromatography used
 Comparison of the Rf or retention-time
values between questioned and known
drugs
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Probable or conclusive
identification tests
 Spectrophometry
or mass spectroscopy
 Data can separate a complex mixture and
then unequivocally identify each substance
in the mixture
 Match the spikes to known substances to
identify
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Human Analysis
for Drugs
 Blood

Liver tissue
 Urine

Brain tissue
 Vitreous

Kidney tissue
 Bile

Spleen tissue
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