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Forensic Analysis of Drugs: Drug Categories. Drug = a natural or synthetic substance that is used to produce physiological or psychological effects Why important to forensics? 75+ % of evidence analyzed in crime labs is drug related - PowerPoint PPT Presentation
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Forensic Analysis of
Drugs:Drug Categories
• Drug = a natural or synthetic substance that is used to produce physiological or psychological effects
• Why important to forensics?– 75+ % of evidence analyzed in crime labs is drug
related– Huge expansion in analytic capabilities of drug
labs to process these samples
Drug Dependence
• Psychological– Emotional need (can be severe)– Craving
• Physical– Brought on by regular use– Experience withdrawl symptoms when abruptly
stopped (can result in death)
Narcotics
• Def: analgesic/pain killing substance that depresses vital body funtions (BP, pulse, breathing)
• Regular use results in physical dependence• “narcotic” often used incorrectly for any drug
that is socially unacceptable• Derivatives of opium
Narcotics• Morphine
– extracted from opium• Heroin – react morphine with acetyl anhydride– water soluble (IV use), 35% pure (lots of fillers!)
• Codeine– In morphine but usually synthesized in lab– 1/6 the strength of morphine
• Fentanyl– 100x more potent than morphine
Narcotics- not derived from opium but considered opiates
• Methadone– related to heroin and used to treat addiction
• Prescription pain killers– Percocet– often abused due to addictive nature
Hallucinogens
• Def: substance that induces changes in mood, attitude, though or perception
• Can cause psychological dependence
• Many derived from natural substances
Hallucinogens
• Marijuana– From Cannabis plant– Most widely used illicit drug– Active ingredient THC (2-20%)– Medical uses: glaucoma, muscle relaxant, nausea
Hallucinogens
• Peyote– From cactus– Used by American Indians to induce religious
experience
• Magic Mushrooms– Psilocybin = similar to serotonin– High doses can impair cognition
Hallucinogens• LSD = lysergic acid diethylamide– From ergot (fungus that attacks grasses)– Very potent– Flashbacks and psychotic episodes even after
discontinued use• PCP = phencylidine– Synthetic – made from toxic chemicals– Often mixed with other drugs– LT use can lead to suicide, schizophrenia
Hallucinogens
• MDMA/Ecstasy– Synthetic– Originally patented as appetite suppressant– Severe adverse reactions = severe anxiety,
paranoia, etc
Depressants
• Def: substance used to depress the functions of the CNS. Calms irritability and may induce sleep.
• Most can cause physical dependence
Depressants
• Alcohol– Most widely used legal drug– High levels can cause fatal depression of
circulatory and respiratory functions• Barbiturates– Powerful sedatives– Used in medical profession• Quaaludes have similar effect
Depressants
• Tranquilizers– Cause relaxation w/o inducing sleep– Valium and other anti-anxiety meds
• Glue sniffing, huffing, etc
Stimulants
• Def: substance taken to increase alertness. Increase BP, breathing, pulse
• Some cause psychological dependence
Stimulants
• Amphetamines– Meth, phen-phen– Increases alertness but over time causes
depression, anxiety and paranoia
• Cocaine/Crack– Extracted from leaves of coca plant
Anabolic Steroids
• Chemically related to testosterone• Promote muscle growth• Can cause “roid rage”, depression, infertility,
premature stop in bone growth
Drug Schedules
• 5 schedules based on potential for abuse/dependence and medical value
• Schedule I – high potential for abuse/dependence– low medical value
• Schedule V– low potential for abuse/dependence– high medical value
Forensic Analysis of
Drugs:Drug Testing
• Most drugs are composed of a mixture of the active ingredient and fillers/additives.
• This “cutting” is used to stretch the drug so that more money can be made.
• Common additives include sugar, starch, and quinine.
Scheme of Analysis for Determining the Identity of a Drug
– Screening Tests• Used to reduce the number of possibilities to a
manageable number• Quick tests but non-specific in nature. Must be
followed up with confirmation tests.
– Confirmation Tests• Tests used to specifically identify a substance.
Screening Tests
– Color Tests• Drug turns a characteristic color when brought into
contact with certain chemicals.
Screening Tests
– Microcrystalline Tests• Several crystals of the drug are examined under a
microscope and a preliminary identification is made based on the shape and color of the crystals.• Impurities can alter the crystals and throw off results.
Screening Tests
– Chromatography• Used to separate mixtures based on the preferential
affinity (attraction) to the stationary phase or the moving phase.• Used to purify the drug by separating it from the
additives/fillers• Compare Rf values to controls to make an ID
Formula: Rf = distance individual spot moves
distance solvent (moving phase) moves
Screening Tests
• Chromatography
Confirmation Tests
Drugs must be PURE
in order to perform these tests
Confirmation Tests
– Infrared (IR) Spectrophotometry• Electromagnetic radiation is absorbed differently by
chemical bonds in a substance• Provides a unique chemical fingerprint
Confirmation Tests
Mass Spectrophotometry• High energy electrons are shot at a substance breaking
the bonds and creating smaller fragments.• Provides a unique chemical fingerprint• Often used in combination with gas chromatography
(called GS-MS; gas chromatography-mass spectrophotometry)– GC- separates drug from impurities–MS- provides unique chemical ID based on patterns
of fragmentation
Mass Spectrophotometry
Analysis of Marijuana
– Different analysis due to botanical nature– Combination of 2 tests provides conclusive results
1) a specific color test2) microscopic analysis to look for cystolithic hairs (aka “bear claws”) on the leaf
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