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Presumptive Drug Tests Screening for drugs or “What could that white powder be?” Retrieved from:

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1 Presumptive Drug Tests Screening for drugs or “What could that white powder be?” Retrieved from: id=1289&dataid=1245&FileName=Presumptive_Drug_Tests.ppt id=1289&dataid=1245&FileName=Presumptive_Drug_Tests.ppt

2 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

3 Controlled Substance Analysis Unknown Substance Plant? Confirmation Tests Micro Crystal GC/MS IR Microscopic Examination Macroscopic Examination Screening Tests Chemical Color Micro Crystal TLC GC/FID UV/Vis Chemical Exam Duquenois TLC GC/FID GC/MS No Yes

4 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

5 Hashish Resin from marijuana that has been isolated Cake is smoked Oil is added to other substances and smoked Contains concentrated cannabinoids

6 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

7 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

8 Proving It’s Pot Three tests must be positive!  Microscopic botanical characteristics present?  Positive Duquenois Levine Test?  Positive TLC?

9 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

10 Magic Mushrooms Psilocybe cubensis  Off white stems with blue-gray staining  Off white to tan caps Active ingredients  psilocin  psilocybin

11 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

12 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 psilocinseratonin (neurotransmitter)

13 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

14 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

15 Chemical Color Tests Detection limits of 1 to 50 µg Can be used as developers for TLC plates

16 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

17 Color Tests Methamphetamine/ Marquis Reagent 2% formaldehyde in Sulfuric acid Methamphetamine/ Sodium Nitroprusside Heroin/ Marquis Reagent Heroin/ Mecke Reagent

18 Color Test Kits Add suspected substance to the pouch. Seal Break ampoules in order Check for color change =Redwop&Product_Code=7624&Category_Code=narcotest

19 Color Test Sequences Mayer’s Narcotics or Amphetamines White precip Barbituates No precip Marquis Dillye- Koppanyi Opiates purple Amphetamines Orange to red to brown Demerol brown Mescaline red Ecstasy black Nitric Acid Heroin yellow Morphine Red to orange to yellow Barbituates blue Mandelin’s Amphetamines Olive green confirms Methadone Dark blue 16 different tests are available

20 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

21 Microcrystalline Tests Cocaine Methamphetamine

22 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

23 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

24 Solubility Guidelines Acidic DrugsBasic DrugsNeutral Drugs Acidic Water Solutions InsolubleSoluble Basic Water Solutions SolubleInsolubleSoluble Neutral Water Solutions Free acid is Insoluble Free base is Insoluble Soluble Organics Free acid is Soluble Free base is Soluble Soluble

25 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


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