Download - Presumptive Drug Tests
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Presumptive Drug Tests
Screening for drugs or
What could that white
powder be?
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Presumptive Tests
Pros
Quick, inexpensive, on the scene
Can be used for elimination purposes
Cons
Cannot be used in court
Do not definitively identify a drug
Do not quantify amount
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Controlled Substance Analysis
Unknown
Substance
Plant?
Confirmation
TestsMicro Crystal
GC/MS
IR
Microscopic
Examination
MacroscopicExamination
Screening TestsChemical Color
Micro Crystal
TLC
GC/FID
UV/Vis
Chemical ExamDuquenois
TLC
GC/FID
GC/MS
NoYes
YesYes
Yes
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Marijuana
Cannabis sativa
Macroscopic Tests Palmate leaf with
serrated edges Fluted stems
Red thread in bud
Microscopic Tests Bear claw shaped
hairs on top surfaceof leaf
Small crystals atbase of leaf
http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/marij.shtml
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Hashish
Resin from marijuana
that has been isolated
Cake is smoked
Oil is added to other
substances and
smoked
Contains concentrated
cannabinoids
https://reader003.{domain}/reader003/html5/0228/5
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Duquesnois-Levine Test
Test for presence of cannabinols, the active agent inmarijuana
Duquenois agent is 2% vanillin, 1% acetaldehyde in ethanol
Purple color denotes a positive test
http://www.dea.gov/photo_library4.html
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Thin Layer Chromatography
Establishes the presence of specificcannabinoids
Provides a color test
Positive if patterns match those of a knownreference run at the same time
http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/add_tests.shtml
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Proving Its Pot
Three tests must be positive!
Microscopic botanical characteristics
present? Positive Duquenois Levine Test?
Positive TLC?
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Peyote
Macroscopic Buttons 1 in diameter
5-10 orange like
segments White tuft in each
segment
Chemical Test Chromatography to
identify characteristicpattern of alkaloids
Mescaline is activeingredient
http://www.chm.bris.ac.uk/motm/psilocybin/psilocybin.wrl -
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Magic Mushrooms
Psilocybe cubensis
Off white stems
with blue-graystaining
Off white to tan
caps
Active ingredients psilocin
psilocybin
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Magic Mushrooms
Characteristic UV spectra
Separate Using TLC then use UV light
to image spots
Color Tests
Purple with pDMBA (Van Urks)
Red with fast blue B that then turns blue
when HCl is added
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Magic Mushrooms
Possession of mushrooms is not illegal Proof of presence of psilocin or psilocybin is
necessary to convict
Psilocybin is fragile and easily converts topsilocin, so you have to prove the psilocinwas there initially
psilocybinpsilocin seratonin
(neurotransmitter)
http://www.chm.bris.ac.uk/motm/psilocybin/serotonin.wrlhttp://www.chm.bris.ac.uk/motm/psilocybin/psilocin.wrlhttp://www.chm.bris.ac.uk/motm/psilocybin/psilocybin.wrl -
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Magic Mushrooms
Psilocybin will break down during gaschromatography Pre-react molecule to stabilize it
Use Mass Spectroscopy to identify the reaction product
Chemical extraction with methanol prior to IR canbreak it down Cant separate psilocin from psilocybin
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Chemical Color Tests
Use reagents that produce specific colorswhen reacting with certain classesofcompounds Target the functional groups
Phenols
Aromatic rings
Primary, secondary and tertiary amines
Chemically adding an auxochrometo drugmolecule that shifts the optical absorptioninto the visible
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Chemical Color Tests
Detection limits of 1 to 50 g
Can be used as developers for TLC
plates
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Chemical Color Tests
Need positive and negative controls to
ensure reagents are reliable
Colors are influenced by Examiners subjectivity
Concentration
Diluents
Adulterants
Age of reagent
Length of time reaction is observed
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Color Tests
Methamphetamine/
Marquis Reagent
2% formaldehyde inSulfuric acid
Methamphetamine/
Sodium Nitroprusside
Heroin/
Marquis Reagent
Heroin/
Mecke Reagent
http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/cct.shtml#photo8
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Color Test Kits
Add suspected
substance to the
pouch. Seal
Break ampoules in
order
Check for color
change
http://www.crime-scene.com/ecpi/A-800-60XX.shtml
http://shop.armorforensics.com/mm5/merchant.mvc?Screen=PROD&Store_Code
=Redwop&Product_Code=7624&Category_Code=narcotest
http://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://shop.armorforensics.com/mm5/merchant.mvc?Screen=PROD&Store_Codehttp://shop.armorforensics.com/mm5/merchant.mvc?Screen=PROD&Store_Codehttp://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://www.crime-scene.com/ecpi/A-800-60XX.shtmlhttp://www.crime-scene.com/ecpi/A-800-60XX.shtml -
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Color Test Sequences
Mayers
Narcotics or
Amphetamines
White precip
Barbituates
No precip
MarquisDillye-
Koppanyi
Opiates
purple
AmphetaminesOrange to red to
brown
Demerol
brown
Mescaline
red
Ecstasy
black
Nitric Acid
Heroin
yellowMorphine
Red to orange
to yellow
Barbituates
blue
Mandelins
Amphetamines
Olive green confirms
Methadone
Dark blue
http://www.bvda.com/EN/prdctinf/pf_en_np.html
16 different tests are
available
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Microcrystal Tests
Sample is dissolved insolution
Reagent is addedgenerating a precipitate
Precipitate has uniquelyshaped crystals
Must have a referencestandard using samereagent
Potential problems
Impurities can distortcrystal shapes
High concentration leadsto small crystals
Reagent age effects
GHB date-rape drug
Crystals following additionOf silver nitrate
http://www.lincoln.ac.uk/fabs/Research/Date%20rape%20research.htm
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Microcrystalline Tests
http://www.dps.state.ia.us/DCI/Crime_Lab/images/blue42.jpg
Cocaine Methamphetamine
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Thin Layer Chromatography
The trick is getting the compounds out
of the solid sample and on the plate
Chemical Extractions Physical extraction
Dry wash and dry extraction
Liquid/liquid extractions
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Types of Drugs
Basic drugs have an acid (HCl, etc.) as
part of their salt form
Acidic drugs have a base (Na, K) aspart of their salt form
Neutral drugs dont have an
associated salt form
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Solubility Guidelines
Acidic Drugs Basic Drugs Neutral Drugs
Acidic Water
SolutionsInsoluble Soluble Soluble
Basic Water
SolutionsSoluble Insoluble Soluble
Neutral Water
SolutionsFree acid is
Insoluble
Free base is
Insoluble
Soluble
Organics Free acid is
Soluble
Free base is
Soluble
Soluble
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Liquid/Liquid Extraction
Dissolve in acidic aqueous solution Basic drugs dissolve
Add organic solvent and shake Acid and neutral drugs go into organic Remove organic solvent after separation
Make aqueous solution basic Basic drugs become insoluble
Add second organic and agitate Basic drugs dissolve in organic
Separate solvents
Use organic fraction for IR or GC/MS