Download - Presumptive Drug Tests Screening for drugs or “What could that white powder be?” Retrieved from:
Presumptive Drug Tests
Screening for drugs or
“What could that white powder be?”
Retrieved from: http://www.whrhs.org/site/handlers/filedownload.ashx?moduleinstanceid=1289&dataid=1245&FileName=Presumptive_Drug_Tests.ppt
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
Controlled Substance Analysis
Unknown Substance
Plant?
ConfirmationTests
Micro CrystalGC/MS
IR
Microscopic Examination
MacroscopicExamination
Screening TestsChemical ColorMicro Crystal
TLCGC/FIDUV/Vis
Chemical ExamDuquenois
TLCGC/FIDGC/MS
NoYes
Yes
Yes
Yes
Marijuana
Cannabis sativa Macroscopic Tests
Palmate leaf with serrated edges
Fluted stems Red “thread” in bud
Microscopic Tests Bear claw shaped
hairs on top surface of leaf
Small crystals at base of leaf
http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/marij.shtml
Hashish
Resin from marijuana that has been isolated
Cake is smoked Oil is added to other
substances and smoked
Contains concentrated cannabinoids
http://www.dea.gov/photos/hash/hash2.jpg
Duquesnois-Levine Test
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
Thin Layer Chromatography 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
Proving It’s Pot
Three tests must be positive! Microscopic botanical characteristics
present? Positive Duquenois Levine Test? Positive TLC?
Peyote
Macroscopic Buttons 1” in diameter 5-10 orange like
segments White tuft in each
segment Chemical Test
Chromatography to identify characteristic pattern of alkaloids
Mescaline is active ingredient
Magic Mushrooms
Psilocybe cubensis Off white stems
with blue-gray staining
Off white to tan caps
Active ingredients psilocin psilocybin
Magic Mushrooms
Characteristic UV spectra Separate Using TLC then use UV light
to image spots Color Tests
Purple with pDMBA (Van Urk’s) Red with fast blue B that then turns blue
when HCl is added
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 to
psilocin, so you have to prove the psilocin was there initially
psilocybin psilocin seratonin(neurotransmitter)
Magic Mushrooms
Psilocybin will break down during gas chromatography Pre-react molecule to stabilize it Use Mass Spectroscopy to identify the reaction product
Chemical extraction with methanol prior to IR can break it down Can’t separate psilocin from psilocybin
Chemical Color Tests
Use reagents that produce specific colors when reacting with certain classes of compounds Target the functional groups
Phenols Aromatic rings Primary, secondary and tertiary amines
Chemically adding an auxochrome to drug molecule that shifts the optical absorption into the visible
Chemical Color Tests
Detection limits of 1 to 50 µg Can be used as developers for TLC
plates
Chemical Color Tests
Need positive and negative controls to ensure reagents are reliable
Colors are influenced by Examiner’s subjectivity Concentration Diluents Adulterants Age of reagent Length of time reaction is observed
Color Tests
Methamphetamine/Marquis Reagent2% 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
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.shtmlhttp://shop.armorforensics.com/mm5/merchant.mvc?Screen=PROD&Store_Code=Redwop&Product_Code=7624&Category_Code=narcotest
Color Test Sequences
Mayer’s
Narcotics orAmphetaminesWhite precip
BarbituatesNo precip
MarquisDillye-
Koppanyi
Opiatespurple
AmphetaminesOrange to red tobrown
Demerolbrown
Mescalinered
Ecstasyblack
Nitric Acid
Heroinyellow
MorphineRed to orange to yellow
Barbituatesblue
Mandelin’s
AmphetaminesOlive green confirms
MethadoneDark blue
http://www.bvda.com/EN/prdctinf/pf_en_np.html
16 different tests areavailable
Microcrystal Tests
Sample is dissolved in solution
Reagent is added generating a precipitate
Precipitate has 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
http://www.lincoln.ac.uk/fabs/Research/Date%20rape%20research.htm
Microcrystalline Tests
http://www.dps.state.ia.us/DCI/Crime_Lab/images/blue42.jpg
Cocaine Methamphetamine
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
Types of Drugs
Basic drugs have an acid (HCl, etc.) as part of their salt form
Acidic drugs have a base (Na, K) as part of their salt form
Neutral drugs don’t have an associated salt form
Solubility Guidelines
Acidic Drugs Basic Drugs Neutral Drugs
Acidic Water Solutions
Insoluble Soluble Soluble
Basic Water Solutions
Soluble Insoluble Soluble
Neutral Water Solutions
Free acid is Insoluble
Free base is Insoluble
Soluble
Organics Free acid is Soluble
Free base is Soluble
Soluble
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