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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