Forensics CTE Test Chapter 11: Drugs
What is a controlled substance analog? Why are such substances considered schedule I drugs?
A controlled substance analog is a chemical substance substantially similar in chemical structure to a controlled substance. They are considered schedule I drugs to combat the proliferation of "designer drugs"--substances that are chemically related to some controlled drugs but are not listed under schedule I.
What is a precursor? How is possession of a precursor treated under the Controlled Substances Act?
A precursor is a chemical compound used by clandestine drug laboratories to synthesize drug of abuse. The Controlled Substances Act provides severe penalties for a person who possesses a listed precursor chemical with the intent to manufacture a controlled substance. Precursors to PCP, amphetamines, and methamphetamines are regulated in the same manner as Schedule II substances.
In what area does mass spectrometry currently have its greatest application for forensic scientists?
At present, mass spectrometry finds its wildest application in areas relating to the identification of drugs.
What major advantage does infrared spectrophotometry enjoy over ultraviolet spectrophotometry?
Because different materials always have distinctively different infrared spectra, the IR spectrum of each substance is unique. Thus, unlike UV spectrophotometry, IR spectrophotometry can reliably identify specific substances.
What is Beer's law and what analytical technique is based on it?
Beer's law states that the quantity of light absorbed at any frequency is directly proportional to the concentration of material absorbing it; the more material one has, the more radiation it will absorb. Beer's law permits spectrophotometry to be used as a technique for quantification.
Under what class of drugs is cocaine listed according to the U.S. federal drug laws? Explain why this classification is pharmacologically incorrect.
Cocaine is classified as a narcotic under current federal law. However, cocaine is actually a powerful central nervous system stimulant, whereas narcotics are analgesic or pain-killing substances that exert a depressant effect on the central nervous system.
What two goals must laboratory testing accomplish to positively identify a drug?
Confirmation tests must produce a combination of results that are characteristic of only one chemical substance--the drug under investigation. Furthermore, experimental evidence must confirm that the probability of any other substance responding in an identical manner to the scheme selected is so small as to be beyond any reasonable scientific certainty.
How can excessive use of depressants cause death?
Excessive use of depressants can decrease the activity of the central nervous system dramatically, causing the body to cease breathing or circulating blood, which can lead to death.
What two chromatographic processes are most applicable for solving analytical problems typically encountered in the crime laboratory? What is the main advantage of each?
Gas chromatography and thin-layer chromatography (TLC) are most applicable for solving analytical problems in the crime laboratory. Gas chromatography is widely used because of its ability to resolve a highly complex mixture into its components, usually within minutes. TLC is inexpensive and allows numerous samples to be analyzed simultaneously on one thin-layer plate.
What opium derivative is most widely used by addicts? How is it typically administered? Give two reasons why this route of administration is popular.
Heroin is the opium derivative most frequently used by addicts. It usually is injected intravenously because by injection its effects are felt almost instantaneously and with maximum sensitivity. In addition, heroin's high solubility in water makes its street preparation for intravenous administration rather simple.
How does a color test work? What is the main limitation of a color test for identifying drugs?
In a color test, a chemical reagent turns a specific color when brought into contact with a particular drug. The main limitation of color tests is that they are useful for screening purposes only and are never taken as conclusive identification of unknown drugs.
Describe how a microcrystalline test works. Name two advantages of microcrystalline tests.
In a microcrystalline test, a drop of a chemical reagent added to a small quantity of drug on a microscopic slide produces crystals that are highly characteristic of the drug. Two advantages of these tests are that they are rapid and they often do not require the isolation of a drug from its diluents.
Briefly describe the basic chromatographic process. Be sure to explain how motion is important to the process.
In one form of chromatography, a questioned mixture is dissolved in liquid so that some of its molecules enter the surrounding air as gas molecules, while others remain in the liquid. During the process, the air containing the gas molecules is forced to move continuously in one direction over the liquid. If one component of the mixture has a greater percentage of its molecules in the moving (gas) phase than other components, those molecules travel over the liquid at a faster pace. When the moving phase has advanced a reasonable distance, the molecules of the different components are completely separated from one another. This allows the scientist to identify the various components in the mixture.
Briefly describe the basic process of spectrophotometry.
In spectrophotometry, a beam of radiation is passed through a tube containing an unknown sample dissolved in a solution. A detector then compares the intensity of radiation passing through the solution to the intensity of a similar beam of radiation that does not pass through the solution. A signal from the detector is then fed into a recorder that produces an absorption spectrum that characterizes the sample being tested.
What is the most widely used illicit drug in the United States? Under what class of drugs is it listed and what are its short-term physical and psychological effects at low moderate doses?
Marijuana is the most widely used illicit drug in the United States today. It is classified as a hallucinogen. At low doses the user may experience an increased sense of well-being; initial restlessness and hilarity followed by a state of relaxation; alteration of sensory perceptions; a more vivid sense of touch, sight, smell, taste, and sound; feelings of hunger; and subtle changes in thought formation and expression.
Name two physiological factors and two nondrug factors that influence drug dependence.
Physiological factors influencing drug dependence include the nature of the drug, the route of administration, the dose, the frequency of administration, and the individual's rate of metabolism. Nondrug factors that play a role in drug dependence include personal characteristics of the user, his or her expectations about the drug experience, society's attitudes and possible responses, and the setting in which the drug is used.
On what three criteria does the Controlled Substances Act classify dangerous substances?
The Controlled Substances Act classifies dangerous substances on the basis of their potential for abuse, their potential for physical and psychological dependence, and their medical value.
List and describe the two phases in a criminalist's scheme of action for identifying a drug.
The first phase is to run screening tests to reduce the number of possible drugs to a small and manageable number. The second phase of the analysis involves employing specific tests, or confirmations, to pinpoint and confirm the drug's identity.
What is the main strength and main weakness of ultraviolet spectrophotometry?
The main strength of UV spectrophotometry is that the spectra it produces are very simple, which makes determining a material's probable identity easier. The main drawback of UV spectrophotometry is that UV spectra of different substances can be similar, so the technique may not provide a definitive result.
What is the most important drawback to gas chromatography?
The most important drawback of gas chromatography is that a forensic chemist cannot identify an unknown substance based solely on the results of gas chromatography.
What is the most popular club drug? Name three negative health effects associated with chronic use of the drug.
The most popular club drug is Ecstasy. Health effects associated with chronic use include seizures, muscle breakdown, stroke, kidney failure, cardiovascular system failure, and damage to the areas of the brain responsible for thought and memory.
What is the source of most narcotic drugs? From what plant is the substance derived?
The source of most analgesic narcotics is opium, which is derived from the poppy.
How are ultraviolet spectrophotometry and infrared spectrophotometry used in drug analysis?
Ultraviolet spectrophotometry is a useful technique for establishing the probable identity of a drug. Infrared spectrophotometry is one of the few analytical techniques available to the chemist that can specifically identify a substance.
What is the most widely abused drug in the United States? Under what class of drugs is listed
and what are its short-term physical and psychological effects at low to moderate doses?,Alcohol is the most widely abused drug in the United States. It is classified as a depressant. Low doses of alcohol tend to inhibit the mental processes of judgment, memory, and concentration. At low to moderate doses alcohol causes the user to become expansive and exude confidence, reduces coordination substantially, inhibits orderly thought processes and speech patterns, and slows down reaction time.
Name the two most commonly abused illegal stimulants and the smokable forms of each. Why does smoking provide a more intense drug experience than inhaling
or "snorting," stimulants?,The two most commonly abused illegal stimulants are amphetamines and cocaine. Their smokable forms are ice and crack, respectively. Smoking causes a more intense drug experience than "snorting" because it causes the drug to enter the bloodstream more quickly and to reach the brain faster.
Name two club drugs that are associated with drug-facilitated sexual assault
rape, and robbery. Why are these drugs relatively easy to administer to an unsuspecting victim?,GHB and Rohypnol are central nervous system depressants that are often connected with drug-facilitated sexual assault, rape, and robbery. Both drugs are odorless, colorless, and tasteless and so will remain undetected when slipped into a drink.
According to the Controlled Substances Act
what is the legal difference between a schedule I drug and a schedule II drug?,Schedule I drugs have no accepted medical value in the United States; schedule II drugs may have medical use with severe restrictions.