“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.”

Chapter 7 Drugs

• “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

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.

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.

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.

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.

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

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

Controlled Drugs

• Hallucinogens

• Stimulants

• Narcotics

• Depressants

LSD

Cocaine

Crack Cocaine

Marijuana

Meth Supplies

Meth Affects

Identification of Drugs

• PDR—Physicians’ Desk Reference

• Field Tests—presumptive tests

• Laboratory Tests—conclusive tests

Human Components Used for Drug Analysis

• Blood

• Urine

• Hair

• Gastric Contents

• Bile

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.

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

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

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.

Types of Chromatography

• Paper

• Thin Layer (TLC)

• Gas (GC)

• Pyrolysis Gas (PGC)

• Liquid (LC)

• High Pressure Liquid (HPLC)

• Column

Paper Chromatography

• Stationary phase—paper

• Mobile phase—a liquid solvent

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

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).

Gas Chromatography

• Phases

• Stationary—a solid or a viscous liquid that lines a tube or column

• Mobile—an inert gas like nitrogen or helium

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).

Spectroscopy

• Spectroscopy—the interaction of electromagnetic radiation with matter.

• Spectrophotometer—an instrument used to measure and record the absorption spectrum of a chemical substance.

Spectrophotometry

• Components

• 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

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

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.

Mass Spectrometry

• In a mass spectrometer, an electron beam is directed at sample molecules in a vacuum chamber. The electrons break apart the sample molecules into many positive charged fragments. These are sorted and collected according to their mass-to-charge ratio by an oscillating electric or a magnetic field.

Mass Spectra

• Each molecular species has its own unique mass spectrum.

IR Spectrophotometry and Mass Spectrometry

• Both work well in identifying pure substances.

• Mixtures are difficult to identify in both techniques

• Both are compared to a catalog of knowns

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.

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.