Presumptive Drug Tests

1. Presumptive Drug Tests Screening for drugs or “What could that white powder be?”

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

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 http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/marij.shtml

5. 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

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 http://www.dea.gov/photo_library4.html

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 http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/add_tests.shtml

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 psilocin seratonin (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 Heroin/ Marquis Reagent Methamphetamine/ Sodium Nitroprusside Heroin/ Mecke Reagent http://www.dps.state.ia.us/DCI/Crime_Lab/Controlled_Substance/cct.shtml#photo8

18. 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

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

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 http://www.lincoln.ac.uk/fabs/Research/Date%20rape%20research.htm

21. Microcrystalline Tests Cocaine Methamphetamine http://www.dps.state.ia.us/DCI/Crime_Lab/images/blue42.jpg

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

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