Transcript Drug Identification_Short Version

Drug Identification
Drug Identification
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The challenge of forensic drug
identification comes in selecting the
correct procedure(s) that will ensure a
specific identification of a drug
3 ways to identify drugs
1.
2.
3.
PDR- Physician’s Desk Reference
Laboratory Tests- conclusive tests
Field Tests- presumptive tests
Controlled Substance Analysis
Unknown
Substance
Yes
Macroscopic
Examination
Yes
Microscopic
Examination
No
Plant?
Screening Tests
Chemical Color
Micro Crystal
TLC
GC/FID
UV/Vis
Yes
Yes
Chemical Exam
Duquenois
TLC
GC/FID
GC/MS
Confirmation
Tests
Micro Crystal
GC/MS
IR
PDR
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Physician’s Desk Reference
A quick and an easy identifier of
manufactured pills, tablets, and capsules
Updated each year
Provides:
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a picture of a drug,
whether it is a prescription, over the counter, or a
controlled substance,
other detailed information about the drug
Presumptive Tests
A presumptive test is an analysis of a
sample which establishes either:
 The sample is definitely not a certain
substance (“rule out”)
 Probable identification (“could be…”)
Presumptive Tests
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Pros
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Quick, inexpensive, on the scene
Can be used for elimination purposes
Cons
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Cannot be used in court
Does not definitively identify a drug
Does not quantify amount
Presumptive Tests
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Include:
1.
2.
Spot or color tests
Microcrystalline test
Spot or Color Tests
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Use reagents that produce specific colors
when reacting with certain classes of
compounds
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Chemically adding an auxochrome to drug
molecule that shifts the optical absorption into
the visible spectrum
Need positive and negative controls to
ensure reagents are reliable
Spot or Color Tests
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Colors are influenced by
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Examiner’s subjectivity
Concentration of sample
Diluents
Adulterants (impure)
Age of reagent
Length of time reaction is observed
Spot or Color Tests
Test Name
Marquis
Indicator for…
Most opium
derivatives
Results in…
Purple
(heroin, morphine)
Amphetamines
Orange-brown
Dillie-Koppanyl
DuquenoisLevine
Barbiturates
Marijuana
Violet-blue
Purple
VanUrk
LSD
Blue-purple
Scott test
Cocaine
Blue
Color Tests
Methamphetamine/
Marquis Reagent
2% formaldehyde in
Sulfuric acid
Methamphetamine/
Sodium Nitroprusside
Heroin/
Marquis Reagent
Heroin/
Mecke Reagent
http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/cct.shtml#photo8
Color Test Kits
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Add suspected
substance to the
pouch.
Seal
Break ampoules in
order
Check for color
change
Color Test Sequences
Narcotics or
Amphetamines
White precip
Barbituates
No precip
Mayer’s
Demerol
brown
Opiates
purple
Marquis
DillyeKoppanyi
Ecstasy
black
Mescaline
red
Nitric Acid
Amphetamines
Orange to red to
brown
Heroin
yellow
Morphine
Red to orange
to yellow
Barbituates
blue
Mandelin’s
Methadone
Dark blue
Amphetamines
Olive green confirms
16 different tests are
available
http://www.bvda.com/EN/prdctinf/pf_en_np.html
Confirmatory Tests
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Can determine the exact identity of the
substance
Includes…
Spectroscopy
•
Ultraviolet (UV)
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Visible
•
Infrared (IR)
Screen solid samples for
potential illicit substances
Chromatography (liquid/gas)
•
Microcrystalline
Confirm that the illegal
substance is present and to
identify it
Mass spectrometry
Systematically quantified
Forensic Autopsy
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Look for
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Irritated tissues
Characteristic odors
Mees line
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Single transverse white bands on nails
Order toxicological screens to identify all
the drugs and toxic compounds that
are potentially present in a sample
Human Specimens for Analysis
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Blood
Urine
Vitreous humor of eye
Bile
Gastric contents
Liver tissue
Brain tissue
Kidney tissue
Hair
Nails
Spectroscopy
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The interaction of electromagnetic
radiation (light) with matter
Measured using a spectrophotometer
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An instrument used to measure and
record the absorption spectrum
(absorbed/reflected) of a chemical
substance
Spectrophotometer
Thin Layer Chromatography
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Establishes the presence of specific
cannabinoids
Provides a color test
Positive if patterns match those of a known
reference run at the same time
http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/add_tests.shtml
Thin Layer Chromatography
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The trick is getting the compounds out
of the solid sample and on the plate
Chemical Extractions
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Physical extraction
Dry wash and dry extraction
Liquid/liquid extractions
Microcrystal Tests
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Sample is dissolved in solution
Reagent is added generating a
precipitate, which will have
uniquely shaped crystals
Must have a reference standard
using same reagent
Potential problems
 Impurities can distort crystal
shapes
 High concentration leads to
small crystals
 Reagent age effects
GHB “date-rape drug”
Crystals following addition
Of silver nitrate
Microcrystalline Tests
Cocaine
Methamphetamine
http://www.dps.state.ia.us/DCI/Crime_Lab/images/blue42.jpg
Mass Spectrometry
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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 positively
charged pieces that are sorted and
collected according to their mass to
charge ratio by a magnetic field
Pattern that results is used to identify
the sample
Field Tests
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Preliminary tests
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Used to determine the degree of
suspect’s physical impairment and
whether or not another test is justified
Psychophysical tests
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3 basic tests exist
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Horizontal gaze nystagmus (HGN)
Nine step walk and turn (WAT)
One leg stand (OLS)
Field Tests
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Horizontal gaze nystagmus (HGN
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Nine step walk and turn (WAT)
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Follow a pen or small flashlight, tracking left to
right with one’s eyes
Wavering at 45 degrees indicates BAC of 0.10
Comprehend and execute two or more simple
instructions at a time
One leg stand (OLS)
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Maintain balance, comprehend and execute two
or more simple instructions at one time
The Breathalyzer
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More practical in the field
Collects and measures alcohol content
of alveolar breath
Breath sample mixes with 3 ml of
0.025% potassium dichromate in
sulfuric acid and water
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Measures light absorption of potassium
dichromate before and after the reaction
with alcohol
Duquesnois-Levine Test
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Test for presence of cannabinols, the active agent in
marijuana
Duquenois agent is 2% vanillin, 1% acetaldehyde in ethanol
Purple color denotes a positive test
http://www.dea.gov/photo_library4.html
Heavy Metals and Fertilizers
Type of Poison
Symptom/Evidence
Caustic poison (lye)
Burns around the lips and mouth
Carbon monoxide
Red or pink patches on chest & thighs
Sulfuric acid
Black vomit
Hydrochloric acid
Greenish-brown vomit
Nitric acid
Yellow vomit
Phosphorus
Coffee brown vomit, onion or garlic odor
Cyanide
Burnt almond odor
Arsenic, mercury
Pronounced diarrhea
Methyl (wood) or
isopropyl alcohol
Nausea, vomiting, unconsciousness,
blindness