chapter 7 & 8 drugs and toxicology “having sniffed the dead man’s lips, i detected a...
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Chapter 7 & 8
Drugs and Toxicology
“Having sniffed the dead man’s lips, I detected a slightly sour smell, and I came to the conclusion that he had
poison forced upon him.”
—Sherlock Holmes, in Sir Arthur Conan Doyle’s
A Study in Scarlet
Chapter 7
Define
®Drug
®Controlled Substance
®Illicit Drug
®Prescription Drug
®Over the Counter Drug
®Poison
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Drug
®A natural or synthetic substance designed to affect humans or animals psychologically or physiologically.
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Controlled substance
®Identified under the Federal Schedules of the Controlled Substances Act
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Illicit Drug
®An illegal substance used for pleasure but not necessarily defined in the Federal Controlled Substance Act
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Prescription Drug
®A doctor must prescribe a drug for a specific reason.
®Misuse makes it an illicit drug.
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Over the Counter (OTC)
®No restrictions on purchase
®Misuse of these can and does occur
®Pseudoephedrine misuse leads to curtailed access
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Chapter 7
Poison
®Almost anything can be a poison if used inappropriately
®Poison Control Center frequent calls®Children’s Tylenol®Children’s Vitamins with iron
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Chapter 7 & 8
Drugs and Toxicology
“All substances are poisons. There is none which is not. The right dose differentiates a poison and remedy.”
—Paracelsus (1495-1541). Swiss physician and chemist
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Drugs
How to apply deductive reasoning to a series of analytical data.
The limitations of presumptive (screening) tests.
The relationship between the electromagnetic spectrum and spectroscopic analysis.
The dangers of using prescription drugs, controlled substances, over-the-counter medications, and illegal drugs.
Students will learn:
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Drugs
Chemically identify illicit drug types.
Classify the types of illicit drugs and their negative effects.
Discuss the federal penalties for possession and use of controlled substances.
Explain the need for confirmatory tests.
Students will be able to:
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Drugs
Describe IR, UV-VIS spectroscopy, and GC-MS
Present and interpret data with graphs.
Use the Physicians’ Desk Reference (PDR) to identify pills.
Use technology and mathematics to improve investigations and communications.
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Drugs and Crime
A drug is a natural or synthetic substance designed to affect the subject psychologically or physiologically.
“Controlled substances” are drugs that are restricted by law
Controlled Substances Act is a law that was enacted in 1970; it lists illegal drugs, their category and their penalty for possession, sale or use.
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Controlled Substances Act
Schedule I—high potential for abuse; no currently acceptable medical use in the US; a lack of accepted safety for use under medical supervision
Schedule II—high potential for abuse; a currently accepted medical use with severe restrictions; abuse may lead to severe psychological or physical dependence
Schedule III—lower potential for abuse than the drugs in I or II; a currently accepted medical use in the US; abuse may lead to moderate physical dependence or high psychological dependence
Schedule IV—low potential for abuse relative to drugs in III; a currently accepted medical use in the US; abuse may lead to limited physical or psychological dependence relative to drugs in III
Schedule V—low potential for abuse relative to drugs in IV; currently accepted medical use in the US; abuse may lead to limited physical or psychological dependence relative to drugs in IV
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Examples of Controlled Substances and Their Schedule Placement
Schedule I—heroin (diacetylmorphine), LSD, marijuana, ecstasy (MDMA)
Schedule II—cocaine, morphine, amphetamines (including methamphetamines), PCP, Ritalin
Schedule III—intermediate acting barbiturates, anabolic steroids, ketamine
Schedule IV—other stimulants and depressants including Valium, Xanan, Librium, phenobarbital, Darvon
Schedule V—codeine found in low doses in cough medicines
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Identification of Drugs
PDR—Physicians’ Desk Reference
Field Tests—presumptive tests
Laboratory Tests—conclusive tests
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Physicians’ Desk Reference
PDR—a physicians’ desk reference is used to identify manufactured pills, tablets and capsules. It is updated each year. This can sometimes be a quick and easy identifier of the legally made drugs that may be found at a scene. The reference book gives a picture of the drug, whether it is a prescription, over the counter, or a controlled substance; as well as more detailed information about the drug.
Chapter 7
Product Inserts: use the guide to help you interpret your example. Answer these questions on notebook paper.
® 1. Scan your product insert® A. List the generic name and indications® B. List contraindications (and describe what that
means)® C. List warnings and adverse reactions® D. Describe dosage
® 2. Describe “black box warnings” and give 7 examples…check the handout for these.
® Does your product have a black box warning?
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Drug Identification
Screening or presumptive tests Spot or color tests Microcrystalline test—
a reagent is added that produces a crystalline precipitate which is unique for a certain drug.
Chromatography
Confirmatory tests Spectrophotometry
Ultraviolet (UV) Visible Infrared (IR)
Mass spectrometry
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Presumptive Color Tests
Marquis—turns purple in the presence of most opium derivatives and orange-brown with amphetamines
Dillie-Koppanyi—turns violet-blue in the presence of barbiturates
Duquenois-Levine—turns a purple color in the presence of marijuana
Van Urk—turns a blue-purple in the presence of LSD
Scott test—color test for cocaine, blue
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Chromatography
A technique for separating mixtures into their components
Includes two phases—a mobile one that flows past a stationary one.
The mixture interacts with the stationary phase and separates.
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Types of Chromatography
Paper Thin Layer (TLC) Gas (GC) Pyrolysis Gas (PGC) Liquid (LC) High Pressure Liquid (HPLC) Column
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Paper Chromatography
Stationary phase—paper
Mobile phase—a liquid solvent
Capillary action moves the mobile phase through the stationary phase
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Thin Layer Chromatography
Stationary phase— a thin layer of coating (usually alumina or silica) on a sheet of plastic or glass
Mobile phase—a liquid solvent
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Retention Factor (Rf) This is a number that represents
how far a compound travels in a particular solvent
It is determined by measuring the distance the compound traveled and dividing it by the distance the solvent traveled.
If the Rf value for an unknown compound is close to or the same as that for the known compound, the two compounds are likely similar or identical (a match).
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Gas ChromatographyPhases Stationary—a solid or a
viscous liquid that lines a tube or column
Mobile—an inert gas like nitrogen or helium
Analysis Shows a peak that is
proportional to the quantity of the substance present
Uses retention time instead of Rf for the qualitative analysis
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Uses of Gas Chromatography
Not considered a confirmation of a controlled substance
Used as a separation tool for mass spectroscopy (MS) and infrared spectroscopy (IR)
Used to quantitatively measure the concentration of a sample. (In a courtroom, there is no real requirement to know the concentration of a substance. It does not affect guilt or innocence).
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Mass Spectrometry
Gas chromatography has one major drawback, it does not give a specific identification. Mass spectrometry cannot separate mixtures. By combining the two (GCMS), constituents of mixtures can be specifically identified.
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Mass Spectrometer
®A machine used to weigh molecules
®A molecular scale
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How is MS used?
®A mass spectrometer helps scientists®ID molecules®Determine how many molecules are
present®Determine what atoms are in a
molecule®Determine how the atoms are arranged
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Chapter 7
Pocket change sorted
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Chapter 7
Sorting and Counting
POCKET CHANGE
® Penny, nickel, dime, quarter, half dollar, dollar
® Sort change by value or size
® Stack them up to sort them visually
MIXTURE OF MOLECULE AND FRAGMENTS
® Mixture of different molecule fragments
® Sort fragments by mass
® Show amount of each fragment on bar graph
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Chapter 7
Molecular fragments sorted
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Chapter 7
HOW? Using ions
®An ion is an electrically charged atom or molecule
®Molecules must be charged to be measured by a mass spec
®A mass spec “weighs” molecules by electrically attracting and repelling ions with carefully controlled charges and force fields.
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Chapter 7
Let’s get charged up!
®First, the mass spec ionizes (or charges) the molecules
®It also breaks apart the big molecule into pieces…like tearing apart a jigsaw puzzle
®This is called ionization
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Chapter 7
Sort it out!
®It sorts all of these charged particles out by size
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Chapter 7
®Like a pinball machine…a certain amount of force sends the ball where you want it
®A different size ball requires different force
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What do the patterns tell us?MOLECULAR
FINGERPRINTS
MS Fragments...pieces of a puzzle
Scientists recognize the pieces and assemble them to identify the compound.
Each compound produces a unique spectrum.
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Mass Spectra
Each molecular species has its own unique mass spectrum.
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Spectroscopy Spectroscopy—the interaction of
electromagnetic radiation with matter. Spectrophotometer—an instrument used to
measure and record the absorption spectrum of a chemical substance.
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SpectrophotometryComponents
A radiation source A frequency selector A sample holder A detector to convert electromagnetic
radiation into an electrical signal A recorder to produce a record of the signal
Types Ultraviolet Visible Infrared
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Infrared Spectometry
Material absorbs energy in the near-IR region of the electromagnetic spectrum.
Compares the IR light beam before and after passing through a transparent sample.
Result—an absorption or transmittance spectrum Gives a unique view of the substance; like a fingerprint
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IR Spectrophotometry andMass Spectrometry
Both work well in identifying pure substances.
Mixtures are difficult to identify in both techniques
Both are compared to a catalog of knowns
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Human ComponentsUsed for Drug Analysis Blood
Urine
Hair
Gastric Contents
Bile
Liver tissue
Brain tissue
Kidney tissue
Spleen tissue
Vitreous Humor of the Eye
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Challenges of Tox
®Drugs must be isolated from body components, such as urine, blood, brain vitreous humor, stomach contents, liver, bile, brain
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Challenges of Tox
®Drugs in the body are changed chemically as the body metabolizes the drug. Scientists must understand the process and look for the metabolites.
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Challenges of Tox
®If the patient is alive, testing must be fast to provide medical care.
®The quantity of drug present is often important. Remember, the difference between medicine and poison is often the dose.
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Challenges of Tox
®The time involved is important.
®For example, in DUI cases, the body is breaking down alcohol at a predictable rate…people “sober up”
®If the blood sample is taken hours after an accident, scientists will try to calculate what the level was at the time of the accident.
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Chapter 7
ID MJEasy, right?
®It’s a plant
®It’s easy to ID, but difficult for a chemist to defend in court because chemists are not botanists!
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Chapter 7
The DUCK TEST
® Does it look like MJ?® Does it smell like MJ?® Pretty good chance it is MJ.
®The Duck Test
won’t fly in court!
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Chapter 7
QUICK TESTS
®Look for cystolithic hairs
®Do a chemical test for cystolithic hairs® Add HCl® HCl reacts with
CaCO3 in hairs to form bubbles
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Chapter 7
GOOD
®First another presumptive test:®Quick, easy, and sensitive®NOT specific
®Add Duquenois-Levine chemical ®MJ will turn purplish in color®The problem is, so will other things
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Chapter 7
BETTER®Chromatography, a confirmatory test,
but still only screening®Components of MJ are separated using
chromatography®We see them using D-L, but this test offers
more info due to separation
®Dip strip of paper in D-L solution ®Allow colored components to separate
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BEST: prove it with MS
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People of Historical Significance
Arthur Jeffrey Dempster was born in Canada, but studied and received his PhD from the University of Chicago. He began teaching physics there in 1916. In 1918, Dempster developed the first modern mass spectrometer. His version was over 100 times more accurate than previous ones developed, and established the basic theory and design of mass spectrometers that is still used to this day.
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People of Historical Significance
Francis William Aston was a British physicist who won the 1922 Nobel Prize in Chemistry for his work in the invention of the mass spectrograph. He used a method of electromagnetic focusing to separate substances. This enabled him to identify no fewer than 212 of the 287 naturally occurring elemental isotopes.