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11 Drugs

Jesus Abad-EI Colomiaano/AFP/Getty Images

LEARNING OBJECTIVES

After studying this chapter, you should be able to:

• Compare and contrast psychological and physical dependence. • Name and classify the commonly abused drugs. • Describe the laboratory tests normally used in a routine drug identification analysis. • Describe and explain the process of chromatography. • Explain the difference between thin-layer chromatography and gas chromatography. • Describe the utility of ultraviolet and infrared spectroscopy for the identification of organic compounds. • Describe the concept and utility of mass spectrometry for identification analysis. • Understand the proper collection and preservation of drug evidence.

PABLO ESCOBAR, DRUG LORD

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In 1989 Forbes magazine listed Pablo Escobar as the seventh richest man in the world. Escobar began his climb to wealth as a teenage car thief in the streets of Medellin, Colombia, and eventually moved into the cocaine-smuggling business. At the peak of his power in the mid-1980s, he was shipping as much as eleven tons of cocaine per flight in jetliners to the United States. Law enforcement officials estimate that the Medellin cartel controlled 80 percent of the world’s cocaine market and was taking in about $25 billion annually.

Escobar ruthlessly ruled by the gun: murdering, assassinating, and kidnapping. He was responsible for killing three presidential candidates in Colombia, as well as for the storming of the Colombian Supreme Court, which resulted in the murder of half the justices. All the while, Escobar curried favor with the Colombian general public by cultivating a Robin Hood image and distributing money to the poor.

In 1991, hoping to avoid extradition to the United States, Escobar turned himself in to the Colombian government and agreed to be sent to prison. However, the prison compound where he was sent could easily be mistaken for a country club. There he continued his high-flying lifestyle, trafficking by telephone and even murdering a few associates. When the Colombian government attempted to move Escobar to another jail, again fearing extradition to the United States, he escaped.

Pressured by the US government, Colombia organized a task force dedicated to apprehending Escobar. The manhunt for Escobar ended on December 2, 1993, when he was cornered on the roof of one of his hideouts. A shootout ensued, and Escobar was fatally wounded by a bullet behind the ear.

Adrug can be defined as a natural or synthetic substance that is used to produce physiological or psychological effects in humans or other animals. However, criminalists are concerned primarily with a small number of drugs—many of them illicit—that are commonly used for their intoxicating effects. These include marijuana, the most widely used illicit drug in the United States, and alcohol, which is consumed regularly by 90 million Americans. Drug abuse has grown from a problem generally associated with members of the lower end of the socioeconomic ladder to one that cuts across all social and ethnic classes of society. Today, approximately 23 million people in the United States use illicit drugs.

Because of the epidemic proportions of illegal drug use, more than 75 percent of the evidence evaluated by crime laboratories in the United States is drug related (see Figure 11-1). The deluge of drug specimens has necessitated the expansion of existing crime laboratories and the creation of new ones. For many concerned forensic scientists, the crime laboratory’s preoccupation with drug evidence represents a serious distraction that takes time away from evaluating evidence related to homicides and other types of serious crimes. However, the increasing caseloads associated with drug evidence have justified the expansion of forensic laboratory services. This expansion has increased the overall analytical capabilities of crime laboratories.

FIGURE 11-1 A drug bust.

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Syracuse Newspapers/The Image Works

Drug Dependence

In assessing the potential danger of drugs, society has become particularly conscious of their effects on human behavior. In fact, the first drugs to be regulated by law in the early years of the twentieth century were those deemed to have “habit-forming” properties. The early laws were aimed primarily at controlling opium and its derivatives;

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cocaine; and, later, marijuana. The ability of a drug to induce dependence after repeated use is submerged in a complex array of physiological and social factors.

Dependence on different drugs exists in numerous patterns and in all degrees of intensity, and depends on the nature of the drug, the route of administration, the dose, the frequency of administration, and the individual’s rate of metabolism. Furthermore, nondrug factors play an equally crucial role in determining the behavioral patterns associated with drug use. The personal characteristics of the user, his or her expectations about the drug experience, society’s attitudes toward and possible responses to the drug, and the setting in which the drug is used are all major determinants of drug dependence.

The questions of how to define and measure a given drug’s influence on the individual and its danger to society are difficult to assess. The nature and significance of drug dependence must be considered from two overlapping points of view: the interaction of the drug with the individual, and the drug’s impact on society. It will be useful to approach the problem from two distinctly different aspects of human behavior: psychological dependence and physical dependence.

psychological dependence The conditioned use of a drug caused by underlying emotional needs.

physical dependence The physiological need for a drug brought about by its regular use and characterized by withdrawal sickness when administration of the drug is abruptly stopped.

FIGURE 11-2 Young people drinking.

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Daytona Beach New-Journal/Jim Tiller\AP Wide World Photos

PSYCHOLOGICAL DEPENDENCE

The common denominator that characterizes all types of repeated drug use is psychological dependence on continued use of the drug. It is important to discard the unrealistic image that all drug users are hopeless “addicts” who are social dropouts. Most users present a quite normal appearance and remain both socially and economically integrated into the life of the community.

The reasons some people abstain from drugs while others become moderately or heavily involved are difficult if not

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impossible to delineate. Psychological needs arise from numerous personal and social factors that inevitably stem from the individual’s desire to create a sense of well-being and to escape from reality. In some cases, the individual may seek relief from personal problems or stressful situations or may be trying to sustain a physical and emotional state that permits an improved level of performance. Whatever the reasons, the underlying psychological needs and the desire to fulfill them create a conditioned pattern of drug abuse (see Figure 11-2).

The intensity of the psychological dependence associated with a drug’s use is difficult to define and largely depends on the nature of the drug. For drugs such as alcohol, heroin, amphetamines, barbiturates, and cocaine, continued use will probably result in a high degree of involvement. Other drugs, such as marijuana and codeine, appear to have a considerably lower potential for the development of psychological dependence. However, this does not imply that repeated abuse of drugs deemed to have a low potential for psychological dependence is safe or will always produce low psychological dependence. We have no precise way to measure or predict the impact of drug abuse on the individual. Even if a system could be devised for controlling the many possible variables affecting a user’s response, the unpredictability of the human personality would still come into play.

Our general knowledge of alcohol consumption should warn us of the fallacy of generalizing when attempting to describe the danger of drug abuse. Obviously, not all alcohol drinkers are psychologically addicted to the drug; most are “social” drinkers who drink in reasonable amounts and on an irregular basis. Many people have progressed beyond this stage and consider alcohol a necessary crutch for dealing with life’s stresses and anxieties. However, a wide range of behavioral patterns exists among alcohol abusers, and to a large extent, the determination of the degree of psychological dependence must be made on an individual basis. Likewise, it would be fallacious to generalize that all users of marijuana can develop only a low degree of dependence on the drug. A wide range of factors also influences marijuana’s effect, and heavy users of the drug expose themselves to the danger of developing a high degree of psychological dependence.

PHYSICAL DEPENDENCE

Although emotional well-being is the primary motive leading to repeated and intensive use of a drug, certain drugs, taken in sufficient dose and frequency, can produce physiological changes that encourage their continued use. Once the user abstains from such a drug, severe physical illness follows. The desire to avoid this withdrawal sickness, or abstinence syndrome, ultimately causes physical dependence, or addiction. Hence, for the addict who is accustomed to receiving large doses of heroin, the prospect of abstaining and encountering the resulting body chills, vomiting, stomach cramps, convulsions, insomnia, pain, and hallucinations is a powerful inducement for continuing to use.

Interestingly, some of the more widely abused drugs have little or no potential for creating physical dependence. Drugs such as marijuana, LSD, and cocaine create strong anxieties when their repeated use is discontinued; however, no medical evidence attributes these discomforts to physiological reactions that accompany withdrawal sickness. On the other hand, use of alcohol, heroin, and barbiturates can result in the development of physical dependence.

Physical dependence develops only when the drug user adheres to a regular schedule of drug intake; that is, the interval between doses must be short enough so that the effects of the drug never wear off completely. For example, the interval between injections of heroin for the drug addict probably does not exceed six to eight hours. Beyond this time the addict will begin to experience the uncomfortable symptoms of withdrawal. Many users of heroin avoid taking the drug on a regular basis for fear of becoming physically addicted to its use. Similarly, the risk of developing physical dependence on alcohol becomes greatest when the consumption is characterized by a continuing pattern of daily use in large quantities.

Table 11.1 categorizes some of the more commonly abused drugs according to their effects on the body and summarizes their tendency to produce psychological dependence and to induce physical dependence with repeated use.

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SOCIETAL ASPECTS OF DRUG USE

The social impact of drug dependence is directly related to the extent to which the user has become preoccupied with the drug. Here, the most important element is the extent to which drug use has become interwoven in the fabric of the user’s life. The more frequently the drug satisfies the person’s need, the greater the likelihood that he or she will become preoccupied with its use, with a consequent neglect of individual and social responsibilities. Personal health, economic relationships, and family obligations may all suffer as the drug-seeking behavior increases in frequency and intensity and dominates the individual’s life. The extreme of drug dependence may lead to behavior that has serious implications for the public’s safety, health, and welfare.

Drug dependence in its broadest sense involves much of the world’s population. As a result, a complex array of individual, social, cultural, legal, and medical factors ultimately influence society’s decision to prohibit or impose strict controls on a drug’s distribution and use. Invariably, society must weigh the beneficial aspects of the drug against the ultimate harm its abuse will do to the individual and to society as a whole. Obviously, many forms of drug dependence do not carry sufficient adverse social consequences to warrant their prohibition, as illustrated by the widespread use of such drug-containing substances as tobacco and coffee. Although the heavy and prolonged use of these drugs may eventually damage body organs and injure an individual’s health, there is no evidence that they result in antisocial behavior, even with prolonged or excessive use. Hence, society is willing to accept the widespread use of these substances.

We are certainly all aware of the disastrous failure of the United States’ prohibition of alcohol use during the 1920s and also of the current debate on whether marijuana should be legalized. Each of these issues emphasizes the delicate balance between individual desires and needs and society’s concern with the consequences of drug abuse; moreover, this balance is continuously subject to change and reevaluation.

TABLE 11.1 The Potential of Some Commonly Abused Drugs to Produce Dependence with Regular Use

DRUG PSYCHOLOGICAL DEPENDENCE PHYSICAL DEPENDENCE

Narcotics

Morphine High Yes

Heroin High Yes

Methadone High Yes

Codeine Low Yes

Depressants

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Quick Review

• A drug is a natural or synthetic substance that is used to produce physiological or psychological effects in humans or other animals. • Nondrug factors that play a part in drug dependence include the personal characteristics of the user, his or her expectations about the drug experience, society’s attitudes toward and possible responses to the drug, and the setting in which the drug is used. • Physical dependence is defined as a physiological need for a drug that has been brought about by its regular use. Psychological dependence is the conditioned use of a drug caused by underlying emotional needs.

Types of Drugs

NARCOTIC DRUGS

The term narcotic is derived from the Greek word narkotikos, meaning “numbness” or “deadening.” Although pharmacologists classify narcotic drugs as substances that relieve pain and produce sleep, the term narcotic has become popularly associated with any drug that is socially unacceptable. As a consequence of this incorrect perception, many drugs are improperly called narcotics.

narcotic A drug that induces sleep and depresses vital body functions such as blood pressure, pulse rate, and breathing rate.

This confusion has produced legal definitions that differ from the pharmacological actions of many drugs. For example, until the early 1970s, most drug laws in the United States incorrectly designated marijuana as a narcotic. Even today, federal law classifies cocaine as a narcotic drug; however, pharmacologically speaking, cocaine is actually a powerful central nervous system stimulant, possessing properties opposite those normally associated with the depressant effects of a narcotic.

OPIATES

Medical professionals apply the term opiate to most of the drugs properly classified as narcotics. Opiates behave pharmacologically like morphine, which is a painkiller derived from opium—the gummy, milky juice that exudes from cuts made on the unripe pods of the Asian poppy (Papaver somniferium). Although morphine is readily extracted from opium, the most commonly used opium-based drug is heroin, which is produced by reacting morphine with acetic anhydride or acetyl chloride (see Figure 11-3). Heroin’s high solubility in water makes its street preparation for intravenous administration rather simple, and only by injection are heroin’s effects felt almost instantaneously and with maximum sensitivity. To prepare the drug for injection, the addict frequently dissolves it in a small quantity of water in a spoon. The process can be speeded up by heating the spoon over a candle or several matches. The solution is then drawn into a syringe or eyedropper and injected under the skin (see Figure 11-4).

FIGURE 11-3 The opium poppy and its derivatives. Shown are the poppy plant, crude and smoking opium, codeine, heroin, and morphine.

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Pearson Education/PH College

FIGURE 11-4 Heroin paraphernalia.

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Drug Enforcement Administration

Heroin and other narcotic drugs are analgesics—that is, they relieve pain by depressing the central nervous system. Besides being a powerful analgesic, heroin produces a “high” that is accompanied by drowsiness and a deep sense of well-being. The effect is short, generally lasting only three to four hours. Regular use of heroin—or any other narcotic drug—invariably leads to physical dependence, with all its dire consequences.

analgesic A substance that lessens or eliminates pain.

Codeine is also present in opium, but it is usually prepared synthetically from morphine. It is commonly used as a cough suppressant in prescription cough syrup. Codeine, only one-sixth as strong as morphine, is not an attractive street drug for addicts.

SYNTHETIC OPIATES

A number of narcotic drugs are not naturally derived from opium. However, because they have similar physiological effects on the body as the opium narcotics, they are also commonly referred to as opiates.

Methadone is perhaps the best known synthetic opiate. In the 1960s, scientists discovered that a person who received periodic doses of methadone would not get high if he or she then took heroin or morphine. Although methadone is pharmacologically related to heroin, its administration appears to eliminate the addict’s desire for heroin, with minimal side effects. These discoveries led to the establishment of controversial methadone maintenance programs in which heroin addicts receive methadone to reduce or prevent future heroin use. Physicians increasingly prescribe methadone for pain relief. Unfortunately, the wide availability of methadone for legitimate medical purposes has recently led to

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greater quantities of the drug being diverted into the illicit market.

In 1995, the US Food and Drug Administration (FDA) approved the drug OxyContin for use as a painkiller. The active ingredient in OxyContin is oxycodone, a synthetic drug closely related to morphine and heroin in its chemical structure. OxyContin is an analgesic narcotic that has effects similar to those of heroin. It is prescribed for treatment of chronic pain, with doctors writing millions of OxyContin prescriptions each year. The drug has a time-release formula that the manufacturer initially believed would reduce the risk of abuse and addiction. This has not turned out to be the case. It is estimated that close to a quarter of a million individuals abuse the drug.

CLOSER ANALYSIS WHAT’S IN THAT BAG?

The contents of a typical bag of heroin is an excellent example of the uncertainty attached to buying illicit drugs. For many years in the 1960s and into the early 1970s, the average bag contained 15 to 20 percent heroin. Currently, the average purity of heroin obtained in the illicit US market is approximately 35 percent. The addict rarely knows or cares what composes the other 65 percent or so of the material. Traditionally, quinine has been the most common diluent of heroin. Like heroin, it has a bitter taste and was probably originally used to obscure the actual potency of a heroin preparation from those who wished to taste-test the material before buying it. Other diluents commonly added to heroin are starch, lactose, procaine (Novocain), and mannitol.

Because it is a legal drug that is diverted from legitimate sources, OxyContin is obtained very differently from illegal drugs. Pharmacy robberies, forged prescriptions, and theft of the drug from patients with a legitimate prescription are ways abusers access OxyContin. Some abusers visit numerous doctors and receive prescriptions even though their medical condition may not warrant it.

HALLUCINOGENS

Hallucinogens are drugs that can cause marked alterations in normal thought processes, perceptions, and moods. Perhaps the most popular and controversial member of this class of drugs is marijuana.

hallucinogen A substance that induces changes in normal thought processes, perceptions, and moods.

MARIJUANA

Marijuana is the popular name of the plant Cannabis sativa, a weed that will grow wild in most climates. The Cannabis plant contains a chemical known as tetrahydrocannabinol, or THC, which produces the psychoactive effects experienced by users. The THC content of Cannabis varies in different parts of the plant. The greatest concentration is usually found in a sticky resin produced by the plant, known as hashish. Declining concentrations are typically found in the flowers and leaves, respectively. Little THC is found in the stem, roots, or seeds of the plant. The potency and resulting effect of the drug fluctuate, depending on the relative proportion of these plant parts in the marijuana mixture consumed by the user. The most common method of administration is by smoking either the dried flowers and leaves or various preparations of hashish (see Figure 11-5). Marijuana is also occasionally taken orally, typically baked in sweets such as brownies or cookies.

Any study of marijuana’s effect on humans must consider the potency of the marijuana preparation. An interesting insight into the relationship between dosage level and marijuana’s pharmacological effect was presented in the first report of the National Commission on Marijuana and Drug Abuse:

At low, usual “social” doses the user may experience an increased sense of well-being; initial restlessness and

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hilarity followed by a dreamy, carefree state of relaxation; alteration of sensory perceptions including expansion of space and time; a more vivid sense of touch, sight, smell, taste and sound; a feeling of hunger, especially a craving for sweets; and subtle changes in thought formation and expression. To an unknowing observer, an individual in this state of consciousness would not appear noticeably different from his normal state. At higher, moderate doses these same reactions are intensified but the changes in the individual would still be scarcely noticeable to an observer. At very high doses, psychotomimetic phenomena may be experienced. These include

distortion of body image, loss of personal identity, sensory and mental illusions, fantasies and hallucinations.1

FIGURE 11-5 Several rolled marijuana cigarettes lie on a pile of crushed, dried marijuana leaves next to a tobacco cigarette.

Photo courtesy US Department of Justice, Drug Enforcement Administration

Marijuana easily qualifies as the most widely used illicit drug in the United States. For instance, more than 43 million Americans have tried marijuana, according to the latest surveys, and almost half that number may be regular users. In addition to its widespread illegal use, accumulating evidence suggests that marijuana has potential medical uses. Two promising areas of research are marijuana’s reduction of excessive eye pressure in sufferers of glaucoma and the lessening of nausea caused by powerful anticancer drugs. Marijuana may also be useful as a muscle relaxant.

No current evidence suggests that experimental or intermittent use of marijuana causes physical or psychological harm. Marijuana does not cause physical dependence. However, the risk of harm lies instead in heavy, long-term use,

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particularly of the more potent preparations. Heavy users can develop a strong psychological dependence on the drug. Some effects of marijuana use include increased heart rate, dry mouth, reddened eyes, impaired motor skills and concentration, and frequently hunger and an increased desire for sweets.

OTHER HALLUCINOGENS

A substantial number of other substances with widely varying chemical compositions are also used recreationally because of their hallucinogenic properties. These include both naturally occurring substances such as mescaline and psilocybin and synthetically created drugs including lysergic acid diethylamide (LSD) and phencyclidine (PCP).

LSD is synthesized from lysergic acid, a substance derived from ergot, which is a type of fungus that attacks certain grasses and grains. The drug appears in a variety of forms—as a pill, added to a cube of sugar, or absorbed onto a small piece of paper—and is taken orally. Its hallucinogenic effects were first described by the Swiss chemist Albert Hofmann after he accidentally ingested some of the material in his laboratory in 1943. LSD produces marked changes in mood, leading to laughing or crying at the slightest provocation. Feelings of anxiety and tension almost always accompany LSD use. LSD is very potent; as little as 25 micrograms is enough to induce vivid visual hallucinations that can last for about twelve hours. Although physical dependence does not develop with continued use, the individual user may be prone to flashbacks and psychotic reactions even after use is discontinued.

CLOSER ANALYSIS MARIJUANA AND HASHISH

Marijuana is a weed that will grow wild in most climates. The plant grows to a height of 5 to 15 feet and is characterized by an odd number of leaflets on each leaf. Normally each leaf contains five to nine leaflets, all with serrated or sawtooth edges.

The potency of marijuana depends on its form. Marijuana in the form of loose vegetation has an average THC content of about 3 to 4.5 percent. The more potent sinsemilla form averages about 6 to 12 percent in THC content. Sinsemilla is the unfertilized flowering tops of the female Cannabis plants, acquired by removing all male plants from the growing field at the first sign of their appearance. Production of sinsemilla requires a great deal of attention and care, and the plant is therefore cultivated on small plots.

Hashish preparations average about 2 to 8 percent THC. On the illicit drug market, hashish (see photo) usually appears in the form of compressed vegetation containing a high percentage of resin. A particularly potent form of hashish is known as liquid hashish or hashish oil. Hashish in this form is normally a viscous substance, dark green with a tarry consistency. Liquid hashish is produced by efficiently extracting the THC-rich resin from the marijuana plant with an appropriate solvent, such as alcohol. The THC content of liquid hashish typically varies from 8 to 22 percent. Because of its extraordinary potency, one drop of the material can produce a “high.”

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The marijuana leaf.

Courtesy Drug Enforcement Administration, Washington, DC

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Blocks of hashish in front of leaves and flowering tops of the marijuana plant.

Courtesy James King-Holmes, Photo Researchers, Inc.

Abuse of the hallucinogen phencyclidine, commonly called PCP, has recently grown to alarming proportions. Because this drug can be synthesized by simple chemical processes, it is manufactured surreptitiously for the illicit market in so-called clandestine laboratories (see Figure 11-6). These laboratories range from large, sophisticated operations to small labs located in garages or bathrooms. Small-time operators normally have little or no training in chemistry and employ “cookbook” methods to synthesize the drug. Some of the more knowledgeable and experienced operators have been able to achieve clandestine production levels that approach a commercial level of operation.

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CLOSER ANALYSIS SYNTHETIC CANNABIS

A drug that contains synthetic cannabinoids has taken on the street names of K2 and Spice. Spice is typically sprayed onto incense and is usually smoked by users. When synthetic cannabis first went on sale in 2004, it was thought to mimic the effect of cannabis through a mixture of legal herbs. However, laboratory analysis later proved that spice in fact contains synthetic cannabiniods that act on the body in a similar way to the cannabiniods found in marijuana, such as THC. Although its effects are not well documented, extremely large doses of spice may cause negative effects that exceed those from marijuana use, such as increased agitation and vomiting. In 2011, the US Drug Enforcement Agency categorized the synthetic cannabinoids typically found in spice as controlled substances. Spice does not cause a positive drug test for cannabis or other illegal drugs.

Phencyclidine is often mixed with other drugs, such as LSD or amphetamines, and is sold as a powder (known as “angel dust”), capsule, or tablet, or as a liquid sprayed on plant leaves. The drug is smoked, ingested, or sniffed. Following oral intake of moderate doses (1 to 6 milligrams), the user first experiences feelings of strength and invulnerability, along with a dreamy sense of detachment. However, the user soon becomes unresponsive, confused, and agitated. Depression, irritability, feelings of isolation, audio and visual hallucinations, and sometimes paranoia accompany PCP use. Severe depression, tendencies toward violence, and suicide accompany long-term daily use of the drug. In some cases, the PCP user experiences sudden schizophrenic behavior days after the drug has been taken.

DEPRESSANTS

Depressants are drugs that slow down, or depress, the central nervous system. Several types of drugs fall into this category, including the most widely used drug in the United States: alcohol.

FIGURE 11-6 A scene from a clandestine drug laboratory.

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Drug Enforcement Administration

ALCOHOL (ETHYL ALCOHOL)

Many people overlook the fact that alcohol is a drug; however, it exerts a powerful depressant action on the central nervous system. When alcohol enters the bloodstream, it quickly travels to the brain, where it suppresses the brain’s control of thought processes and muscle coordination. Low doses of alcohol tend to inhibit the mental processes of judgment, memory, and concentration. The drinker’s personality becomes expansive, and he or she exudes confidence. When taken in moderate doses, alcohol reduces coordination substantially, inhibits orderly thought processes and speech patterns, and slows reaction times. Under these conditions, the ability to walk or drive becomes noticeably impaired. Higher doses of alcohol may cause the user to become highly irritable and emotional; displays of anger and crying are not uncommon. Extremely high doses may cause an individual to lapse into unconsciousness or even a comatose state that can precede a fatal depression of circulatory and respiratory functions. The behavioral patterns of alcohol intoxication vary and depend partly on such factors as the social setting, the amount consumed, and the personal expectation of the individual with regard to alcohol.

depressant A substance that slows down, or depresses, the functions of the central nervous system.

In the United States, the alcohol industry annually produces more than one billion gallons of spirits, wine, and beer for which 90 million consumers pay nearly $40 billion. Unquestionably, these and other statistics support the fact that alcohol is the most widely used and abused drug (see Figure 11-7).

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BARBITURATES

Barbiturates are derivatives of barbituric acid, a substance first synthesized by a German chemist, Adolf Von Bayer, more than a hundred years ago. They are commonly referred to as “downers” because they relax the user, create a feeling of well-being, and produce sleep. Like alcohol, barbiturates suppress the vital functions of the central nervous system. Twenty-five barbiturate derivatives are currently used in medical practice in the United States; however, only five—amobarbital, secobarbital, phenobarbital, pentobarbital, and butabarbital—are used for most medical applications.

FIGURE 11-7 Rows of bottles of alcohol behind a bar.

Jeremy Liebman/Stone/Getty Images

Normally, barbiturate users take these drugs orally. The average sedative dose is about 10 to 70 milligrams. When taken in this fashion, the drug enters the blood through the walls of the small intestine. Some barbiturates, such as phenobarbital, are classified as long-acting barbiturates. They are absorbed into the bloodstream more slowly than others and therefore produce less pronounced effects than faster-acting barbiturates. The slow action of phenobarbital accounts for its low incidence of abuse. Apparently, barbiturate abusers prefer the faster-acting varieties: secobarbital, pentobarbital, and amobarbital.

In the early 1970s, a nonbarbiturate depressant, methaqualone (brand name Quaalude), appeared on the illicit-drug

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scene. Methaqualone is a powerful sedative and muscle relaxant that possesses many of the depressant properties of barbiturates. When taken in prescribed amounts, barbiturates are relatively safe, but in instances of extensive and prolonged use, physical dependence can develop.

ANTIPSYCHOTIC AND ANTIANXIETY DRUGS

Although antipsychotic and antianxiety drugs can be considered depressants, they differ from barbiturates in the extent of their effects on the central nervous system. Generally, these drugs produce a relaxing tranquility without impairing high-thinking faculties or inducing sleep. Antipsychotics, such as reserpine and chlorpromazine, have been used to reduce the anxieties and tension of mental patients. A group of antianxiety drugs are commonly prescribed to deal with the everyday tensions of many healthy people. These drugs include meprobamate (Miltown), chlordiazepoxide (Librium), diazepam (Valium), and Xanax.

In the past forty-five years, the use of these drugs—particularly antianxiety drugs—has grown dramatically. Medical evidence shows that these drugs produce psychological and physical dependence with repeated and high levels of usage. For this reason, the widespread prescribing of antianxiety drugs to overcome the pressures and tensions of life has worried many people who fear a legalized drug culture is being created.

“HUFFING”

Since the early 1960s, “huffing,” the practice of sniffing materials containing volatile solvents (airplane glue or model cement, for example), has grown in popularity. Another dimension has more recently been added to the problem with the increasing popularity of sniffing aerosol gas propellants such as freon. All materials abused by huffing contain volatile or gaseous substances that are primarily central nervous system depressants. Although toluene (a solvent used in airplane glue) seems to be the most popular solvent to sniff, others can produce comparable physiological effects. These chemicals include naphtha, methyl ethyl ketone (i.e., antifreeze), gasoline, and trichloroethylene (a dry-cleaning solvent).

The usual immediate effects of huffing are a feeling of exhilaration and euphoria combined with slurred speech, impaired judgment, and double vision. Finally, the user may experience drowsiness and stupor, with these depressant effects slowly wearing off as the user returns to a normal state. Although most experts believe that users become psychologically dependent on the effects achieved by huffing, little evidence suggests that solvent inhalation is addictive. However, huffers expose themselves to the danger of liver, heart, and brain damage from the chemicals they have inhaled. Even worse, sniffing of some solvents, particularly halogenated hydrocarbons such as freon and related gases, is accompanied by a significant risk of immediate death.

STIMULANTS

The term stimulants refers to a range of drugs that stimulate, or speed up, the central nervous system.

stimulant A substance that speeds up, or stimulates, the activity of the central nervous system.

AMPHETAMINES

Amphetamines are a group of synthetic stimulants that share a similar chemical structure and are commonly referred to in the terminology of the drug culture as “uppers” or “speed.” They are typically taken either orally or via intravenous injection and provide a feeling of well-being and increased alertness that is followed by a decrease in fatigue and a loss

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of appetite. However, these apparent benefits of the drug are accompanied by restlessness and instability or apprehensiveness, and once the stimulant effect wears off, depression may set in.

In the United States, the most serious form of amphetamine abuse stems from intravenous injection of amphetamine or its chemical derivative, methamphetamine (see Figure 11-8). The desire for a more intense amphetamine experience is the primary motive for this route of administration. The initial sensation of a “flash” or “rush,” followed by an intense feeling of pleasure, constitutes the principal appeal of the intravenous route for the user. During a “speed binge,” the individual may inject amphetamines every two to three hours. Users have reported experiencing a euphoria that produces hyperactivity, with a feeling of clarity of vision as well as hallucinations. As the effect of the amphetamines wears off, the individual lapses into a period of exhaustion and may sleep continuously for one or two days. Following this, the user often experiences a prolonged period of severe depression lasting from days to weeks.

A smokable form of methamphetamine, known as “ice,” is reportedly in heavy demand in some areas of the United States. Ice is prepared by slowly evaporating a methamphetamine solution to produce large, crystal-clear “rocks.” Like crack cocaine (discussed next), ice is smoked and produces effects similar to those of crack cocaine, but the effects last longer. Once the effects of ice wear off, users often become depressed and may sleep for days. Chronic users exhibit violent destructive behavior and acute psychosis similar to paranoid schizophrenia. Repeated use of amphetamines leads to a strong psychological dependence, which encourages their continued use.

FIGURE 11-8 Granular amphetamine beside a razor blade.

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COCAINE

Between 1884 and 1887, pioneering psychologist Sigmund Freud created something of a sensation in European medical circles by describing his experiments with a new drug. He reported a substance of seemingly limitless potential as a source of “exhilaration and lasting euphoria” that permitted “intensive mental or physical work [to be] performed without fatigue.” He wrote, “It is as though the need for food and sleep was completely banished.”

FIGURE 11-9 Coca leaves and illicit forms of cocaine.

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Drug Enforcement Administration

The object of Freud’s enthusiasm was cocaine, a stimulant extracted from the leaves of Erythroxylon coca, a plant grown in the Andes mountains of South America as well as in tropical Asia (see Figure 11-9). Most commonly, cocaine is sniffed or “snorted” and absorbed into the body through the mucous membranes of the nose, but it is sometimes injected. Cocaine is a powerful stimulant to the central nervous system, and its effects resemble those caused by amphetamines—namely, increased alertness and vigor accompanied by suppression of hunger, fatigue, and boredom. Cocaine produces a feeling of euphoria by stimulating a pleasure center in the base of the brain, in an area connected to nerves that are responsible for emotions. It stimulates this pleasure center to a far greater degree than it would ever normally be stimulated. Some regular users of cocaine report accompanying feelings of restlessness, irritability, and anxiety. Cocaine used chronically or at high doses can have toxic effects. Cocaine-related deaths result from cardiac arrest or seizures followed by respiratory arrest.

A particularly potent form of cocaine known as “crack” can be produced by mixing cocaine with baking soda and water and then heating the resulting solution. This material is then dried and broken into tiny chunks that dealers sell as

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crack “rocks” that are sufficiently volatile to be smoked. The faster the cocaine level rises in the brain, the greater the euphoria, and the fastest way to attain a rise in the brain’s cocaine level is to smoke crack. Inhaling the cocaine vapor delivers the drug to the brain in less than fifteen seconds—about as fast as injecting it and much faster than snorting it. The dark side of crack, however, is that the euphoria fades quickly as the cocaine levels rapidly drop, leaving the user feeling depressed, anxious, and pleasureless. The desire to return to the euphoric feeling is so intense that crack users quickly develop a habit for the drug that is almost impossible to overcome. Only a small percentage of crack abusers are ever cured of this drug habit. When a person uses large amounts of crack cocaine numerous times, he or she usually develops a sense of paranoia. Paronoid delusions cause the person to lose his or her sense of reality, leaving him or her trapped in a world full of voices, whispers, and suspicions. Sufferers come to believe that they are being followed and that their drug use is being watched.

In the United States, cocaine abuse is on the rise. Many people are using cocaine apparently to improve their ability to work and to keep going when tired. Although there is no evidence of physical dependency accompanying cocaine’s repeated use, abstention from cocaine after prolonged use brings on severe bouts of mental depression, which produce a very strong compulsion to resume using the drug. In fact, laboratory experiments with animals have demonstrated that, of all the commonly abused drugs, cocaine produces the strongest psychological compulsions for continued use.

The United States spends millions of dollars annually in attempting to control cultivation of the coca leaf in various South American countries and to prevent the trafficking of cocaine into the United States. Three-quarters of the cocaine smuggled into the United States was refined in clandestine laboratories in Colombia. The profits are astronomical. Peruvian farmers may be paid $200 for enough coca leaves to make one pound of cocaine. The refined cocaine is worth $1,000 when it leaves Colombia and sells at retail in the United States for up to $20,000.

CLUB DRUGS

The term club drugs refers to synthetic drugs that are often used at nightclubs, bars, and raves (i.e., all-night dance parties). Substances that are used as club drugs include, but are not limited to, MDMA (or Ecstasy; see Figure 11-10), GHB (gamma hydroxybutyrate), Rohypnol (“roofies”), ketamine, and methamphetamine. These drugs have become popular on the dance scene as a way to induce the rave experience. A high incidence of use has been found among teens and young adults.

GHB and Rohypnol are central nervous system depressants that are often connected with drug-facilitated sexual assault, rape, and robbery. Effects accompanying the use of GHB include dizziness, sedation, headache, and nausea. Recreational users have reported euphoria, relaxation, disinhibition, and increased libido (i.e., sex drive). Rohypnol causes muscle relaxation, loss of consciousness, and an inability to remember what happened during the hours after ingesting the drug. Users of this drug are at particular risk of sexual assault because victims are physically unable to resist the attack. Effects are even stronger when the drug is combined with alcohol because the user experiences memory loss, blackouts, and disinhibition. Unsuspecting victims of intentional druggings become drowsy or dizzy. Drugs such as Rohypnol and GHB are odorless, colorless, and tasteless, and thus remain undetected when slipped into a drink.

FIGURE 11-10 Ecstasy, a popular club drug.

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Courtesy Rusty Kennedy, AP Wide World Photos

Methylenedioxymethamphetamine, also known as MDMA or Ecstasy, is a synthetic, mind-altering drug that exhibits many hallucinogenic and amphetamine-like effects. Ecstasy was originally patented as an appetite suppressant and was later discovered to induce feelings of happiness and relaxation. Recreational drug users find that Ecstasy enhances self- awareness and decreases inhibitions. However, seizures, muscle breakdown, stroke, kidney failure, and cardiovascular system failure often accompany chronic abuse of Ecstasy. In addition, chronic use of Ecstasy leads to serious damage to the areas of the brain responsible for thought and memory. Ecstasy increases heart rate and blood pressure; produces muscle tension, teeth grinding, and nausea; and causes psychological difficulties such as confusion, severe anxiety, and paranoia. The drug can cause significant increases in body temperature from the combination of the drug’s stimulant effect with the often hot, crowded atmosphere of a rave club.

Ketamine is primarily used in veterinary medicine as an animal anesthetic. When used by humans, the drug can cause euphoria and feelings of unreality accompanied by visual hallucinations. Ketamine can also cause impaired motor function, high blood pressure, amnesia, and mild respiratory depression.

ANABOLIC STEROIDS

Anabolic steroids are synthetic compounds that are chemically related to the male sex hormone testosterone. Testosterone has two effects on the body. It promotes the development of secondary male characteristics (i.e., androgenic effects), and it accelerates muscle growth (i.e., anabolic effects). Efforts to promote muscle growth and to

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minimize the hormone’s androgenic effects have led to the synthesis of numerous anabolic steroids. However, a steroid free of the accompanying harmful side effects of an androgen drug has not yet been developed.

anabolic steroids Synthetic compounds, chemically related to the male sex hormone testosterone, that are used to promote muscle growth.

Incidence of steroid abuse first received widespread public attention when both amateur and professional athletes were discovered using these substances to enhance their performance. Interestingly, current research on male athletes given anabolic steroids has generally found little or, at best, marginal evidence of enhanced strength or performance. Although the full extent of anabolic steroid abuse by the general public is not fully known, the US government is sufficiently concerned to regulate the availability of these drugs to the general population and to severely punish individuals for illegal possession and distribution of anabolic steroids. In 1991, anabolic steroids were classified as controlled dangerous substances, and the Drug Enforcement Administration was given enforcement power to prevent their illegal use and distribution (see Figure 11-11).

Anabolic steroids are usually taken by individuals who are unfamiliar with their harmful medical side effects. Liver cancer and other liver malfunctions have been linked to steroid use. These drugs also cause masculinizing effects in females, infertility, and diminished sex drive in males. For teenagers, anabolic steroids result in the premature halting of bone growth. Anabolic steroids can also cause unpredictable effects on mood and personality, leading to unprovoked acts of anger and destructive behavior. Depression is also a frequent side effect of anabolic steroid abuse.

FIGURE 11-11 Anabolic steroids: a vial of testosterone and a syringe. Testosterone, the male sex hormone, is sometimes abused by athletes for its protein-building (anabolic) effect.

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Quick Review

• Narcotic drugs are analgesics, meaning that they relieve pain by depressing the central nervous system. • The most common source for narcotic drugs is opium. Morphine is extracted from opium and used to synthesize heroin. • Opiates are not derived from opium or morphine, but they have the same physiological effects on the body. Examples of opiates are methadone and OxyContin (i.e., oxycodone). • Hallucinogens cause marked changes in normal thought processes, perceptions, and moods. Marijuana is the most well-known drug in this class. Other hallucinogens include LSD, mescaline, PCP, psilocybin, and MDMA (or Ecstasy). • Depressants decrease the activity of the central nervous system, calm irritability and excitability, and produce sleep. Depressants include alcohol (i.e., ethanol), barbiturates, tranquilizers, and various substances that can be sniffed such as airplane glue and model cement. • Stimulants increase the activity of the central nervous system and are taken to increase alertness and activity. Stimulants include amphetamines, sometimes known as “uppers” or “speed,” and cocaine, which in its free-base form is known as “crack.” • Club drugs are synthetic drugs that are used at nightclubs, bars, and raves (i.e., all-night dance parties). Some club drugs act as stimulants; others have depressant effects. • Anabolic steroids are synthetic compounds that are chemically related to the male sex hormone testosterone. Anabolic steroids are often abused by individuals who are interested in accelerating muscle growth.

Drug-Control Laws

The provisions of drug laws are of particular interest to the criminalist, for they may impose specific analytical requirements on drug analysis. For example, the severity of a penalty associated with the manufacture, distribution, possession, and use of a drug may depend on the weight of the drug or its concentration in a mixture. In such cases, the chemist’s report must contain all information that is needed to properly charge a suspect under the provisions of the existing law.

The provisions of any drug-control law are an outgrowth of national and local law enforcement requirements and customs, as well as the result of moral and political philosophies. These factors have produced a wide spectrum of national and local drug-control laws. Although their detailed discussion is beyond the intended scope of this book, a brief description of the US federal law known as the Controlled Substances Act will illustrate a legal drug classification system that has been created to prevent and control drug abuse. Many states have modeled their own drug-control laws after this act, an important step in establishing uniform drug-control laws throughout the United States.

Collection and Preservation of Drug Evidence

Preparation of drug evidence for submission to the crime laboratory is normally relatively simple and accomplished with minimal precautions in the field. The field investigator must ensure that the evidence is properly packaged and labeled for delivery to the laboratory. Considering the countless forms and varieties of drug evidence that are seized, it is not practical to prescribe any single packaging procedure for fulfilling these requirements. Generally, common sense is the best guide in such situations, keeping in mind that the package must prevent loss and/or cross-contamination of the contents. Often, the original container in which the drug was seized will meet these requirements. Specimens

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suspected of containing volatile solvents, such as those involved in glue-sniffing cases, must be packaged in an airtight container to prevent evaporation of the solvent. All packages must be marked with sufficient information to ensure identification by the officer in future legal proceedings and to establish the chain of custody.

To aid the drug analyst, the investigator should supply any background information that may relate to a drug’s identity. Analysis time can be markedly reduced when the chemist has this information. For the same reason, the results of drug-screening tests used in the field must also be transmitted to the laboratory. However, although these tests may indicate the presence of a drug and may help the officer establish probable cause to search and arrest a suspect, they do not offer conclusive evidence of a drug’s identity.

Quick Review

• Federal law establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s potential for abuse, potential for physical and psychological dependence, and medical value. • The packaging of drug evidence must prevent loss and/or cross-contamination of the contents, and often the original container in which the drug was seized is used. Specimens suspected of containing volatile solvents must be packaged in an airtight container to prevent evaporation. • The investigator may help in the identification of the drug by supplying to the drug analyst any background information that may relate to the drug’s identity.

CLOSER ANALYSIS CONTROLLED SUBSTANCES ACT

The federal Controlled Substances Act establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s potential for abuse, potential for physical and psychological dependence, and medical value. This classification system is extremely flexible in that the US attorney general has the authority to add, delete, or reschedule a drug as more information becomes available.

Schedule I. Schedule I drugs have a high potential for abuse, have no currently accepted medical use in the United States, and/or lack accepted safety for use in treatment under medical supervision. Drugs controlled under this schedule include heroin, marijuana, methaqualone, and LSD. Schedule II. Schedule II drugs have a high potential for abuse, a currently accepted medical use or a medical use with severe restrictions, and a potential for severe psychological or physical dependence. Schedule II drugs include opium and its derivatives not listed in schedule I, cocaine, methadone, phencyclidine (PCP), most amphetamine preparations, and most barbiturate preparations containing amobarbital, secobarbital, and pentobarbital. Dronabinol, the synthetic equivalent of the active ingredient in marijuana, has been placed in schedule II in recognition of its growing medical uses in treating glaucoma and chemotherapy patients. Schedule III. Schedule III drugs have less potential for abuse than those in schedules I and II, a currently accepted medical use in the United States, and a potential for low or moderate physical dependence or high psychological dependence. Schedule III controls, among other substances, all barbiturate preparations (except phenobarbital) not covered under schedule II and certain codeine preparations. Anabolic steroids were added to this schedule in 1991. Schedule IV. Schedule IV drugs have a low potential for abuse relative to schedule III drugs and have a current medical use in the United States; their abuse may lead to limited dependence relative to schedule III drugs. Drugs controlled in this schedule include propoxyphene (Darvon), phenobarbital, and tranquilizers such as meprobamate (Miltown), diazepam (Valium), and chlordiazepoxide (Librium). Schedule V. Schedule V drugs must show low abuse potential, have medical use in the United States, and have less potential for producing dependence than schedule IV drugs. Schedule V controls certain opiate drug mixtures that contain nonnarcotic medicinal ingredients.

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Controlled dangerous substances listed in schedules I and II are subject to manufacturing quotas set by the attorney general. For example, eight billion doses of amphetamines were manufactured in the United States in 1971. In 1972, production quotas were established reducing amphetamine production approximately 80 percent below 1971 levels.

CONTROL MECHANISMS OF THE CONTROLLED SUBSTANCES ACT

Schedule Registration Record Keeping

Manufacturing Quotas Distribution Restrictions

Dispensing Limits

I Required Separate Yes Order forms Research use only

II Required Separate Yes Order forms Rx: written; no refills

III Required Readily retrievables

No, but some drugs limited by schedule II quotas

Records required Rx: written or oral; with medical authorization refills up to 5 times in 6 months

IV Required Readily retrievable

No, but some drugs limited by schedule II quotas

Records required Rx: written or oral; with medical authorization refills up to 5 times in 6 months

V Required Readily retrievable

No, but some drugs limited by schedule II quotas

Records required Over-the-counter (Rx drugs limited to MD’s order) refills up to 5 times

The criminal penalties for the unauthorized manufacture, sale, or possession of controlled dangerous substances are related to the schedules as well. The most severe penalties are associated with drugs listed in schedules I and II. For example, for drugs included in schedules I and II, a first offense of individual trafficking is punishable by up to twenty years in prison and/or a fine of up to $1 million for an individual or up to $5 million for other than individuals. The table summarizes the control mechanisms and penalties for each schedule of the Controlled Substances Act.

The Controlled Substances Act also stipulates that an offense involving a controlled substance analog—a chemical substance substantially similar in chemical structure to a controlled substance—triggers penalties as if it were a controlled substance listed in schedule I. This section is designed to combat the proliferation of so-called designer drugs—substances that are chemically related to some controlled drugs and are pharmacologically very potent. These substances are manufactured by skilled individuals in clandestine laboratories with the knowledge that their products will not be covered by the schedules of the Controlled Substances Act. For instance, fentanyl is a powerful narcotic that is commercially marketed for medical use and is also listed as a controlled dangerous substance. This drug is about one hundred times as potent as morphine. A number of substances chemically related to fentanyl have been synthesized by underground chemists and sold on the street. The first such substance we know of was sold under the street name China White. These drugs have been responsible for more than a hundred overdose deaths in California

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and nearly twenty deaths in western Pennsylvania. As designer drugs such as China White become identified by drug officials and linked to drug abuse, they are placed in appropriate schedules.

The Controlled Substances Act also reflects an effort to decrease the prevalence of clandestine drug laboratories designed to manufacture controlled substances. The act regulates the manufacture and distribution of precursors, the chemical compounds used by clandestine drug laboratories to synthesize abused drugs. Targeted precursor chemicals are listed in the definition section of the Controlled Substances Act. Severe penalties are assigned to a person who possesses a listed precursor chemical with the intent to manufacture a controlled substance or who possesses or distributes a listed chemical knowing, or having reasonable cause to believe, that the listed chemical will be used to manufacture a controlled substance. In addition, precursors to PCP, amphetamines, and methamphetamines are enumerated specifically in schedule II, making them subject to regulation in the same manner as other schedule II substances.

IMPORT-EXPORT

Narcotic Nonnarcotic Security Manufacturer/Distributor Reports to

Drug Enforcement Administration

Criminal Penalties for Individual Trafficking

(First Offense)

Permit Permit Vault/safe Yes 0-20 years/$1 million

Permit Permit Vault/safe Yes 0-20 years/$1 million

Permit Declaration Secure storage area

Yes, narcotic; no, nonnarcotic 0-5 years/$250,000

Permit Declaration Secure storage area

Manufacturer only, narcotic; no, nonnarcotic

0-3 years/$250,000

Permit to import; declaration to export

Declaration Secure storage area

Manufacturer only, narcotic; no, nonnarcotic

0-1 year/$100,000

Source: Drug Enforcement Administration, Washington, DC

Forensic Drug Analysis

One only has to look into the evidence vaults of crime laboratories to appreciate the assortment of drug specimens that confront the criminalist. The presence of a huge array of powders, tablets, capsules, vegetable matter, liquids, pipes, cigarettes, cookers, and syringes is testimony to the vitality and sophistication of the illicit-drug market. If outward appearance is not evidence enough of the difficult analytical chore facing the forensic chemist, consider the complexity of the drug preparations themselves. Usually these contain active drug ingredients of unknown origin and identity, as

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well as additives—for example, sugar, starch, and quinine—that dilute their potency and stretch their value on the illicit-drug market. Do not forget that illicit-drug dealers are not hampered by government regulations that ensure the quality and consistency of their product.

When a forensic chemist picks up a drug specimen for analysis, he or she can expect to find just about anything, so all contingencies must be prepared for. The analysis must leave no room for error because its results will have a direct bearing on the process of determining the guilt or innocence of a defendant. There is no middle ground in drug identification—either the specimen is a specific drug or it is not—and once a positive conclusion is drawn, the chemist must be prepared to support and defend the validity of the results in a court of law.

SCREENING AND CONFIRMATION

The challenge or difficulty of forensic drug identification comes in selecting analytical procedures that will ensure a specific identification of a drug. Presented with a substance of unknown origin and composition, the forensic chemist must develop a plan of action that will ultimately yield the drug’s identity. This plan, or scheme of analysis, is divided into two phases.

First, faced with the prospect that the unknown substance may be any one of a thousand or more commonly encountered drugs, the analyst must employ screening tests to reduce these possibilities to a small and manageable number. This objective is often accomplished by subjecting the material to a series of color tests that produce characteristic colors for the more commonly encountered illicit drugs. Even if these tests produce negative results, their value lies in having excluded certain drugs from further consideration.

screening test A preliminary test used to reduce the number of possible identities of an unknown substance.

Once the number of possibilities has been reduced substantially, the second phase of the analysis must be devoted to pinpointing and confirming the drug’s identity. In an era in which crime laboratories receive voluminous quantities of drug evidence, it is impractical to subject a drug to all the chemical and instrumental tests available. Indeed, it is more realistic to look on these techniques as constituting a large analytical arsenal. The chemist, aided by training and experience, must choose tests that will most conveniently identify a particular drug.

Forensic chemists often use a specific test to identify a drug substance to the exclusion of all other known chemical substances. A single test that identifies a substance is known as a confirmation. The analytical scheme sometimes consists of a series of nonspecific or presumptive tests. Each test in itself is insufficient to prove the drug’s identity; however, the proper analytical scheme encompasses a combination of test results that characterize one and 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.

confirmation A single test that specifically identifies a substance.

Another consideration in selecting an analytical technique is the need for either a qualitative or a quantitative determination. The former relates just to the identity of the material, whereas the latter refers to the percentage of each component in the mixture. Hence, a qualitative identification of a powder may reveal the presence of heroin and quinine, whereas a quantitative analysis may conclude the presence of 10 percent heroin and 90 percent quinine.

Obviously, a qualitative identification must precede any attempt at quantitation; there is little value in attempting to quantitate a material without first determining its identity. Essentially, a qualitative analysis of a material requires the determination of numerous properties using a variety of analytical techniques. On the other hand, a quantitative

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measurement is usually accomplished by precise measurement of a single property of the material.

Forensic chemists normally rely on several tests for a routine drug-identification scheme: color tests, microcrystalline tests, chromatography, spectrophotometry, and mass spectrometry.

COLOR TESTS

Many drugs yield characteristic colors when brought into contact with specific chemical reagents. Not only do these tests provide a useful indicator of a drug’s presence, but they are also used by investigators in the field to examine materials suspected of containing a drug (see Figure 11-12). However, color tests are useful for screening purposes only and are never taken as conclusive identification of unknown drugs.

Five primary color-test reagents are as follows:

1. Marquis. The reagent turns purple in the presence of heroin and morphine and most opium derivatives. Marquis becomes orange-brown when mixed with amphetamines and methamphetamines. 2. Dillie-Koppanyi. This is a valuable screening test for barbiturates, in whose presence the reagent turns a violet-blue color. 3. Duquenois-Levine. This is a valuable color test for marijuana, performed by adding a series of chemical solutions to the suspect vegetation. A positive result is shown by a purple color when chloroform is added. 4. Van Urk. The reagent turns blue-purple in the presence of LSD. However, owing to the extremely small quantities of LSD in illicit preparations, this test is difficult to conduct under field conditions. 5. Scott Test. This is a color test for cocaine. A powder containing cocaine turns a cobalt thiocyanate solution blue. Upon the addition of hydrochloric acid, the blue color is transformed to a clear pink color. Upon the addition of chloroform, if cocaine is present, the blue color reappears in the chloroform layer.

FIGURE 11-12 A field color-test kit for cocaine. The suspect drug is placed in the plastic pouch. Tubes containing chemicals are broken open, and the color of the chemical reaction is observed.

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MICROCRYSTALLINE TESTS

A technique considerably more specific than color tests is the microcrystalline test. A drop of a chemical reagent is added to a small quantity of the drug on a microscopic slide. After a short time, a chemical reaction ensues, producing a crystalline precipitate. The size and shape of the crystals, examined under a compound microscope, reveal the identity of the drug. Crystal tests for cocaine and methamphetamine are illustrated in Figure 11-13.

microcrystalline test A test that identifies a specific substance based on the color and shape of crystals formed when the substance is mixed with specific reagents.

FIGURE 11-13 (a) A photomicrograph of a cocaine crystal formed in platinum chloride (400×). (b) A photomicrograph of a methamphetamine crystal formed in gold chloride (400×).

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San Bernardino County Sheriff

Over the years, analysts have developed hundreds of crystal tests to characterize the most commonly abused drugs. These tests can be rapidly executed and often do not require the isolation of a drug from its diluents; however, because diluents can sometimes alter or modify the shape of the crystal, the examiner must develop experience in interpreting the results of the test.

Most color and crystal tests are largely empirical—that is, scientists do not fully understand why they produce the results they do. From the forensic chemist’s point of view, this is not important. When the tests are properly chosen and used in proper combination, they reveal characteristics that identify the substance as a certain drug to the exclusion of all others.

Quick Review

• Analysts use screening tests to determine the identity of drugs present in a sample. These tests reduce the number of possible drugs to a small and manageable number. • A series of color tests produce characteristic colors for the more commonly encountered illicit drugs. In a microcrystalline test, a drop of a chemical reagent added to a small quantity of drug on a microscope slide produces crystals highly characteristic of a drug. • After preliminary testing, forensic chemists use more specific tests to identify a drug substance to the exclusion of all other known chemical substances.

CHROMATOGRAPHY

Chromatography is a means of separating and tentatively identifying the components of a mixture. It is particularly useful for analyzing drug specimens, which may be diluted with practically any material to increase the quantity of the product available to prospective customers. The task of identifying an illicit-drug preparation would be arduous without the aid of chromatographic methods to first separate the mixture into its components.

chromatography Any of several analytical techniques for separating organic mixtures into their components by attraction to a stationary phase while being propelled by a moving phase.

THIN-LAYER CHROMATOGRAPHY

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Thin-layer chromatography (TLC) uses a solid stationary phase and a moving liquid phase to separate the constituents of a mixture. Thin-layer chromatography is a powerful tool for solving many of the analytical problems presented to the forensic scientist. The method is both rapid and sensitive; moreover, less than 100 micrograms of suspect material is required for the analysis. In addition, the equipment necessary for TLC work has minimal cost and space requirements. Importantly, numerous samples can be analyzed simultaneously on one thin-layer plate. This technique is principally used to detect and identify components in complex mixtures.

In TLC, the components of a suspect mixture are separated as they travel up a glass or plastic plate, eventually appearing as a series of dark or colored spots on the plate. This action is then compared to a standard sample separation of a specific drug, such as heroin. If both the standard and the suspect substances travel the same distance up the plate, they can tentatively be identified as being the same substance.

A thin-layer plate is prepared by coating a glass plate or plastic backing with a thin film of a granular material, usually silica gel or aluminum oxide. This granular material serves as the solid stationary phase and is usually held in place on the plate with a binding agent such as plaster of paris. If the sample to be analyzed is a solid, it must first be dissolved in a suitable solvent, then a few microliters of the solution is spotted with a capillary tube onto the granular surface near the lower edge of the plate. A liquid sample may be applied directly to the plate in the same manner. The plate is then placed upright in a closed chamber that contains a selected liquid, but the liquid must not touch the sample spot.

The liquid slowly rises up the plate by capillary action. This rising liquid is the moving phase in thin-layer chromatography. As the liquid moves past the sample spot, the components of the sample become distributed between the stationary solid phase and the moving liquid phase. The components with the greatest affinity for the moving phase travel up the plate faster than those that have greater affinity for the stationary phase. When the liquid front has moved a sufficient distance (usually 10 centimeters), the development is complete, and the plate is removed from the chamber and dried (see Figure 11-14). An example of the chromatographic separation of ink is shown in Figure 11-15.

Often the plate is sprayed with a chemical reagent that reacts with the separated substances and causes them to form colored spots. Figure 11-16 shows the chromatogram of a marijuana extract that has been separated into its components by TLC and visualized by having been sprayed with a chemical reagent.

Figure 11-17 shows a sample suspected of containing heroin and quinine that has been chromatographed alongside known heroin and quinine standards. The distance the unknown material migrated up the suspect plate is compared to the distances that heroin and quinine migrated up a standard sample plate. If the distances are the same, a tentative identification can be made. However, such an identification cannot be considered definitive because numerous other substances can migrate the same distance up the plate when chromatographed under similar conditions. Thus, thin- layer chromatography alone cannot provide an absolute identification; it must be used in conjunction with other testing procedures to prove absolute identity.

FIGURE 11-14 (a) In thin-layer chromatography, a liquid sample is spotted onto the granular surface of a gel-coated plate. (b) The plate is placed into a closed chamber that contains a liquid. As the liquid rises up the plate, the components of the sample distribute themselves between the coating and the moving liquid. The mixture is separated, with substances with a greater affinity for the moving liquid traveling up the plate at a faster speed.

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GAS CHROMATOGRAPHY (GC)

FIGURE 11-15 (a) In thin-layer chromatography, the liquid phase begins to move up the stationary phase. (b) Liquid moves past the ink spot carrying the ink components up the stationary phase. (c) The moving

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liquid has separated the ink into its several components.

Richard Megna\ Fundamental Photographs, NYC

Gas chromatography (GC) separates mixtures based on their distribution between a stationary liquid phase and a moving gas phase. In gas chromatography, the moving phase is called the carrier gas, which flows through a column constructed of glass. The stationary phase is a thin film of liquid within the column, which is known as a capillary column.

FIGURE 11-16 A thin-layer chromatogram of a marijuana extract.

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FIGURE 11-17 Chromatographs of known heroin (1) and quinine (2) standards alongside a suspect sample (3).

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Richard Saferstein

Capillary columns are composed of glass and are 15 to 60 meters in length. These types of columns are very narrow, ranging from 0.25 to 0.75 millimeter in diameter. Capillary columns can be made narrow because their stationary liquid phase is actually a very thin film coating the column’s inner wall.

As the carrier gas flows through the capillary column, it carries with it the components of a mixture that have been

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injected into the column. Components with a greater affinity for the moving gas phase travel through the column more quickly than those with a greater affinity for the stationary liquid phase. Eventually, after the mixture has traversed the length of the column, it emerges separated into its components.

The time required for a component to emerge from the column after its injection into the column is known as the retention time, which is a useful identifying characteristic. Figure 11-18(a) shows the chromatogram of two barbiturates; each barbiturate has tentatively been identified by comparing its retention time to those of known barbiturates, shown in Figure 11-18(b). However, because other substances may have comparable retention times under similar chromatographic conditions, gas chromatography cannot be considered an absolute means of identification. Conclusions derived from this technique must be confirmed with other testing procedures.

CLOSER ANALYSIS THE GAS CHROMATOGRAPH

A simplified scheme of the gas chromatograph is shown in the figure. The operation of the instrument can be summed up briefly as follows: The carrier gas is fed into the column at a constant rate. The carrier gas, generally nitrogen or helium, is chemically inert. The sample under investigation is injected as a liquid into a heated injection port with a syringe, where it is immediately vaporized and swept into the column by the carrier gas. The column itself is heated in an oven in order to keep the sample in a vapor state as it travels through the column. In the column, the components of the sample travel in the direction of the carrier gas flow at speeds that are determined by their distribution between the stationary and moving phases. If the analyst has selected the proper liquid phase and has made the column long enough, the components of the sample will be completely separated as they emerge from the column.

As each component emerges from the column, it enters a detector. One type of detector uses a flame to ionize the emerging chemical substance, thus generating an electrical signal. The signal is recorded on a strip-chart recorder as a function of time. This written record of the separation is called a chromatogram. A gas chromatogram is a plot of the recorder response (on the vertical axis) over time (on the horizontal axis). A typical chromatogram shows a series of peaks, each of which corresponds to one component of the mixture.

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Basic gas chromatography. Gas chromatography permits rapid separation of complex mixtures into individual compounds and allows identification and quantitative determination of each compound. As shown, a sample is introduced by a syringe (1) into a heated injection chamber (2). A constant stream of nitrogen gas (3) flows through the injector, carrying the sample into the column (4), which contains a thin film of liquid. The sample is separated in the column, and the carrier gas and separated components emerge from the column and enter the detector (5). Signals developed by the detector activate the recorder (7), which makes a permanent record of the separation by tracing a series of peaks on the chromatograph (8). The time it takes a component to emerge from the column identifies the component present, and the peak area identifies the concentration.

Courtesy Varian Inc., Palo Alto, CA

WebExtra 11.1

Watch Animated Depictions of Thin-Layer Chromatography and Gas Chromatography www.mycrimekit.com

Gas chromatography is widely used because of its ability to resolve a highly complex mixture into its components, usually within minutes. It has the added advantages of being extremely sensitive and yielding quantitative results. Gas chromatography has sufficient sensitivity to detect and quantitate materials down to the nanogram (i.e., 0.000000001 gram).

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FIGURE 11-18 (a) An unknown mixture of barbiturates is identified by comparing its retention times to (b), a known mixture of barbiturates.

Courtesy Varian Inc., Palo Alto, CA

WebExtra 11.2

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SPECTROPHOTOMETRY

The technique of chromatography is particularly suited for analyzing illicit drugs because it can separate a drug from other substances that may be present in the drug preparation. However, chromatography has the drawback of not being able to specifically identify the material under investigation. For this reason, other analytical tools are frequently used to identify drugs. These include the technique of spectrophotometry, which can identify a substance by exposing it to a specific type of electromagnetic radiation.

spectrophotometry An analytical method for identifying a substance by its selective absorption of different wavelengths of light.

FIGURE 11-19 The frequency of the lower light wave is twice that of the upper wave.

THEORY OF LIGHT

The knowledge of the nature and behavior of light is fundamental to understanding physical properties important to the examination of forensic evidence. One can think of light as a continuous wave. The wave concept depicts light as having the up-and-down motion of a continuous wave, as shown in Figure 11-19. Such a wave can be characterized by two distinct properties: wavelength and frequency. The distance between two consecutive crests (high points) or

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troughs (low points) of a wave is called the wavelength; it is designated by the Greek letter lambda (λ) and is typically measured in nanometers (nm), or millionths of a meter. The number of crests (or troughs) passing any one given point in a unit of time is defined as the frequency of the wave. Frequency is normally designated by the letter f and is expressed in cycles per second (cps). Frequency and wavelength are inversely proportional to one another, as shown by the relationship expressed in the following equation:

F = cλ

In this equation, c represents the speed of light.

wavelength The distance between crests of adjacent waves.

frequency The number of waves that pass a given point per unit of time.

Many of us have held a glass prism up toward the sunlight and watched it transform light into the colors of the rainbow. The process of separating light into its component colors is called dispersion. Visible light usually travels at a constant velocity of nearly 300 million meters per second. However, on passing through the glass of a prism, each color component of light is slowed to a speed slightly different from those of the others, causing each component to bend at a different angle as it emerges from the prism (see Figure 11-20). This bending of light waves results in a change in velocity called refraction.

dispersion The separation of light into its component wavelengths.

refraction The bending of a light wave caused by a change in its velocity.

The observation that a substance has a color is consistent with this description of white light. For example, when light passes through a red glass, the glass absorbs all the component colors of light except red, which passes through or is transmitted by the glass. Likewise, one can determine the color of an opaque object by observing its ability to absorb some of the component colors of light while reflecting others back to the eye. Color is thus a visual indication that objects absorb certain portions of visible light and transmit or reflect others. Scientists have long recognized this phenomenon and have learned to characterize chemical substances by the type and quantity of light they absorb. This has important implications for the identification and classification of forensic evidence.

visible light Colored light ranging from red to violet in the electromagnetic spectrum.

FIGURE 11-20 A representation of the dispersion of light by a glass prism.

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ELECTROMAGNETIC SPECTRUM

Visible light is only a small part of a large family of radiation waves known as the electromagnetic spectrum (see Figure 11-21). All electromagnetic waves travel at the speed of light (c) and are distinguishable from one another only by their different wavelengths or frequencies. Hence, the only property that distinguishes X-rays from radio waves is the different frequencies the two types of waves possess.

electromagnetic spectrum The entire range of radiation energy from the most energetic cosmic rays to the least energetic radio waves.

X-ray A high-energy, short-wavelength form of electromagnetic radiation.

Similarly, the range of colors that make up the visible spectrum can be correlated with frequency. For instance, the lowest frequencies of visible light are red; waves with a lower frequency fall into the invisible infrared (IR) region. The highest frequencies of visible light are violet; waves with a higher frequency extend into the invisible ultraviolet (UV) region. No definite boundaries exist between any colors or regions of the electromagnetic spectrum; instead, each region is composed of a continuous range of frequencies, each blending into the other.

FIGURE 11-21 The electromagnetic spectrum.

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Just as a substance can absorb visible light to produce color, many of the invisible radiations of the electromagnetic spectrum are likewise absorbed. This absorption phenomenon is the basis for spectrophotometry, an analytical technique that measures the quantity of radiation that a particular material absorbs as a function of wavelength or frequency.

FIGURE 11-22 The parts of a simple spectrophotometer.

THE SPECTROPHOTOMETER

An object does not absorb all the visible light it is exposed to; instead, it selectively absorbs some frequencies and reflects or transmits others. Similarly, the absorption of other types of electromagnetic radiation by chemical substances is also selective. Selective absorption of a substance is measured by an instrument called a

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spectrophotometer, which produces a graph or absorption spectrum that depicts the absorption of light as a function of wavelength or frequency.

The spectrophotometer measures and records the absorption spectrum of a chemical. The basic components of a simple spectrophotometer are the same regardless of whether it is designed to measure the absorption of UV, visible, or IR radiation. These components are illustrated diagrammatically in Figure 11-22. They include (1) a radiation source, (2) a monochromator or frequency selector, (3) a sample holder, (4) a detector to convert electromagnetic radiation into an electrical signal, and (5) a recorder to produce a record of the signal.

The measuring absorption of UV, visible, and IR radiation is particularly applicable to obtaining qualitative data pertaining to the identification of drugs.

ULTRAVIOLET AND VISIBLE SPECTROPHOTOMETRY

Ultraviolet (UV) and visible spectrophotometry measure the absorption of UV and visible light as a function of wavelength or frequency. For example, the UV absorption spectrum of heroin shows a maximum absorption band at a wavelength of 278 nanometers (see Figure 11-23). This shows that the simplicity of a UV spectrum facilitates its use as a tool for determining a material’s probable identity. For instance, a white powder may have a UV spectrum comparable to heroin and therefore may be tentatively identified as such. (Fortunately, sugar and starch, common diluents of heroin, do not absorb UV light.)

ultraviolet Invisible long frequencies of light beyond violet in the visible spectrum.

This technique, however, does not provide a definitive result; other drugs or materials may have a UV absorption spectrum similar to that of heroin. Nevertheless, UV spectrophotometry is often useful in establishing the probable identity of a drug. For example, if an unknown substance yields a UV spectrum that resembles that of amphetamine (see Figure 11-24), thousands of substances are immediately eliminated from consideration, and the analyst can begin to identify the material from a relatively small number of possibilities. A comprehensive collection of UV drug spectra provides an index that can rapidly be searched in order to tentatively identify a drug or, failing that, at least to exclude certain drugs from consideration.

FIGURE 11-23 The ultraviolet spectrum of heroin.

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FIGURE 11-24 The ultraviolet spectrum of an amphetamine.

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INFRARED SPECTROPHOTOMETRY

In contrast to the simplicity of a UV spectrum, absorption in the infrared (IR) region provides a far more complex pattern. Figure 11-25 depicts the IR spectra of heroin and secobarbital. Here, the absorption bands are so numerous that each spectrum can provide enough characteristics to identify a substance specifically. Different materials always have distinctively different infrared spectra; each IR spectrum is therefore equivalent to a “fingerprint” of that substance and no other. This technique is one of the few tests available to the forensic scientist that can be considered specific in itself for identification. The IR spectra of thousands of organic compounds have been collected, indexed, and cataloged as invaluable references for identifying organic substances. The selective absorption of light by drugs in the UV and IR regions of the electromagnetic spectrum provides a valuable technique for characterizing drugs.

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infrared Invisible short frequencies of light before red in the visible spectrum.

MASS SPECTROMETRY

The Gas Chromatography section discussed the operation of the gas chromatograph. This instrument is one of the most important tools in a crime laboratory. Its ability to separate the components of a complex mixture is unsurpassed. However, gas chromatography has one important drawback: its inability to produce specific identification. A forensic chemist cannot unequivocally state the identity of a substance based solely on its retention time as determined by the gas chromatograph. Fortunately, by coupling the gas chromatograph to a mass spectrometer, forensic chemists have largely overcome this problem.

A mixture’s components are first separated on the gas chromatograph. A direct connection between the gas chromatograph column and the mass spectrometer then allows each component to flow into the spectrometer as it emerges from the gas chromatograph. In the mass spectrometer, the material enters a high-vacuum chamber where a beam of high-energy electrons is aimed at the sample molecules. The electrons collide with the molecules, causing them to lose electrons and to acquire a positive charge. These positively charged molecules, or ions, are very unstable or are formed with excess energy and almost instantaneously decompose into numerous smaller fragments. The fragments then pass through an electric or magnetic field, where they are separated according to their masses. The unique feature of mass spectrometry is that, under carefully controlled conditions, no two substances produce the same fragmentation pattern. In essence, one can think of this pattern as a “fingerprint” of the substance being examined (see Figure 11-26).

ion An atom or molecule bearing a positive or negative charge.

FIGURE 11-25 (a) The infrared spectrum of heroin. (b) The infrared spectrum of secobarbital.

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Mass spectrometry thus provides a specific means for identifying a chemical structure. It is also sensitive to minute concentrations. Mass spectrometry is widely used to identify drugs; however, further research is expected to yield significant applications for identifying other types of physical evidence. Figure 11-27 illustrates the mass spectra of heroin and cocaine; here, each line represents a fragment of a different mass (actually the ratio of mass to charge), and the line height reflects the relative abundance of each fragment. Note how different the fragmentation patterns of heroin and cocaine are. Each mass spectrum is unique to each drug and therefore provides a specific test for identifying that substance.

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FIGURE 11-26 How GC/MS works. Left to right, the sample is separated into its components by the gas chromatograph, and then the components are ionized and identified by characteristic fragmentation patterns of the spectra produced by the mass spectrometer.

Courtesy Agilent Technologies, Inc., Palo Alto, CA

FIGURE 11-27 (a) The mass spectrum of heroin. (b) The mass spectrum of cocaine.

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The combination of the gas chromatograph and mass spectrometer (GC/MS) is further enhanced when a computer is added to the system. The integrated gas chromatograph/mass spectrometer/computer system provides the ultimate in speed, accuracy, and sensitivity. With the ability to record and store in its memory several hundred mass spectra, such a system can detect and identify substances present in quantities of only one millionth of a gram. Furthermore, the computer can be programmed to compare an unknown spectrum against a comprehensive library of mass spectra stored in its memory. The advent of personal computers and microcircuitry has enabled the design of mass spectrometer systems that can fit on small tables. Such a unit is pictured in Figure 11-28. With data obtained from a GC/MS determination, a forensic analyst can, with one instrument, separate the components of a complex drug mixture and then unequivocally identify each substance present in the mixture.

FIGURE 11-28 A tabletop mass spectrometer. (1) The sample is injected into a heated inlet port, and carrier gas sweeps it into the column. (2) The GC column separates the mixture into its components. (3) In the ion

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source, a filament wire emits electrons that strike the sample molecules, causing them to fragment as they leave the GC column. (4) The quadrupole, consisting of four rods, separates the fragments according to their mass. (5) The detector counts the fragments passing though the quadrupole. The signal is small and must be amplified. (6) The data system is responsible for total control of the entire GC/MS system. It detects and measures the abundance of each fragment and displays the mass spectrum.

Courtesy Agilent Technologies, Inc., Palo Alto, CA

FIGURE 11-29 A scientist injecting a sample into a research-grade mass spectrometer.

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Geoff/Tompkinson/Science Photo Library\Photo Researchers, Inc.

Research-grade mass spectrometers are found in laboratories as larger, floor-model units (see Figure 11-29).

Quick Review

• Chromatography is a means of separating and tentatively identifying the components of a mixture. • Thin-layer chromatography (TLC) uses a solid stationary phase, usually coated onto a glass plate, and a mobile liquid phase to separate the components of the mixture. • Gas chromatography (GC) separates mixtures on the basis of their distribution between a stationary liquid phase and a mobile gas phase. • Spectrophotometry is the measurement of the absorption of light by chemical substances. • Dispersion is the process of separating light into its component colors. Each component bends, or refracts, at a different angle as it emerges from the prism. The large family of radiation waves is known as the electromagnetic spectrum. • Most forensic laboratories use ultraviolet (UV) and infrared (IR) spectrophotometers to characterize chemical compounds. • IR spectrophotometry provides a far more complex pattern than UV spectrophotometry. Because different materials have distinctively different infrared spectra, each IR spectrum is equivalent to a “fingerprint” of that substance. • Mass spectrometry characterizes organic molecules by observing their fragmentation pattern after their

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collision with a beam of high-energy electrons. • Infrared spectrophotometry and mass spectrophotometry typically are used to identify a specific drug substance.

WebExtra 11.3

Watch an Animation of a Mass Spectrometer www.mycrimekit.com

Virtual Lab Drug Identification Analysis

To perform a virtual drug identification analysis, go to www.pearsoncustom.com/us/vlm/

Virtual Lab Thin-Layer Chromatography of Ink

To perform a virtual thin-layer analysis, go to www.pearsoncustom.com/us/vlm/

CHAPTER REVIEW

• A drug is a natural or synthetic substance that is used to produce physiological or psychological effects in humans or other animals. • Nondrug factors that play a part in drug dependence include the personal characteristics of the user, his or her expectations about the drug experience, society’s attitudes toward and possible responses to the drug, and the setting in which the drug is used. • Physical dependence is defined as a physiological need for a drug that has been brought about by its regular use. Psychological dependence is the conditioned use of a drug caused by underlying emotional needs. • Narcotic drugs are analgesics, meaning that they relieve pain by depressing the central nervous system. • The most common source for narcotic drugs is opium. Morphine is extracted from opium and used to synthesize heroin. • Opiates are not derived from opium or morphine, but they have the same physiological effects on the body. Examples of opiates are methadone and OxyContin (i.e., oxycodone). • Hallucinogens cause marked changes in normal thought processes, perceptions, and moods. Marijuana is the most well-known drug in this class. Other hallucinogens include LSD, mescaline, PCP, psilocybin, and MDMA (or Ecstasy). • Depressants decrease the activity of the central nervous system, calm irritability and excitability, and produce sleep. Depressants include alcohol (i.e., ethanol), barbiturates, tranquilizers, and various substances that can be sniffed such as airplane glue and model cement. • Stimulants increase the activity of the central nervous system and are taken to increase alertness and activity. Stimulants include amphetamines, sometimes known as “uppers” or “speed,” and cocaine, which in its freebase form is known as “crack.” • Club drugs are synthetic drugs that are used at nightclubs, bars, and raves (i.e., all-night dance parties). Some club drugs act as stimulants; others have depressant effects. • Anabolic steroids are synthetic compounds that are chemically related to the male sex hormone testosterone. Anabolic steroids are often abused by individuals who are interested in accelerating muscle growth. • Federal law establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s potential for abuse, potential for physical and psychological dependence, and medical value. • The packaging of drug evidence must prevent loss and/or cross-contamination of the contents, and often the

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original container in which the drug was seized is used. Specimens suspected of containing volatile solvents must be packaged in an airtight container to prevent evaporation. • The investigator may help in the identification of the drug by supplying to the drug analyst any background information that may relate to the drug’s identity. • Analysts use screening tests to determine the identity of drugs present in a sample. These tests reduce the number of possible drugs to a small and manageable number. • A series of color tests produce characteristic colors for the more commonly encountered illicit drugs. In a microcrystal-line test, a drop of a chemical reagent added to a small quantity of drug on a microscope slide produces crystals highly characteristic of a drug. • After preliminary testing, forensic chemists use more specific tests to identify a drug substance to the exclusion of all other known chemical substances. • Chromatography is a means of separating and tentatively identifying the components of a mixture. • Thin-layer chromatography (TLC) uses a solid stationary phase, usually coated onto a glass plate, and a mobile liquid phase to separate the components of the mixture. • Gas chromatography (GC) separates mixtures on the basis of their distribution between a stationary liquid phase and a mobile gas phase. • Spectrophotometry is the measurement of the absorption of light by chemical substances. • Dispersion is the process of separating light into its component colors. Each component bends, or refracts, at a different angle as it emerges from the prism. The large family of radiation waves is known as the electromagnetic spectrum. • Most forensic laboratories use ultraviolet (UV) and infrared (IR) spectrophotometers to characterize chemical compounds. • IR spectrophotometry provides a far more complex pattern than UV spectrophotometry. Because different materials have distinctively different infrared spectra, each IR spectrum is equivalent to a “fingerprint” of that substance. • Mass spectrometry characterizes organic molecules by observing their fragmentation pattern after their collision with a beam of high-energy electrons. • Infrared spectrophotometry and mass spectrophotometry typically are used to identify a specific drug substance.

KEY TERMS

anabolic steroids 265

analgesic 256

chromatography 272

confirmation 270

depressant 261

dispersion 277

electromagnetic spectrum 277

frequency 275

hallucinogen 257

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infrared 280

ion 282

microcrystalline test 271

narcotic 255

physical dependence 251

psychological dependence 251

refraction 277

screening test 270

spectrophotometry 275

stimulant 262

ultraviolet 279

visible light 277

wavelength 275

X-ray 278

REVIEW QUESTIONS

1.

A(n) ______ can be defined as a natural or synthetic substance that is used to produce physiological or psychological effects in humans or other animals.

2.

True or False: Underlying emotional factors are the primary motives leading to the repeated use of a drug. ___________

3.

True or False: Drugs such as alcohol, heroin, amphetamines, barbiturates, and cocaine can lead to a low degree of psychological dependence with repeated use._______

4.

The development of _______ dependence on a drug is shown by withdrawal symptoms such as convulsions when the user stops taking the drug.

5.

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True or False: Abuse of barbiturates can lead to physical dependency._______

6.

True or False: Repeated use of LSD leads to physical dependency._______

7.

Physical dependency develops only when the drug user adheres to a(n)_______ schedule of drug intake.

8.

Narcotic drugs are _______ that have _______ effects on the central nervous system.

9.

_______ is a gummy, milky juice exuded from cuts made on the unripe pods of the Asian poppy.

10.

_______ is a chemical derivative of morphine made by reacting morphine with acetic anhydride.

11.

A legally available drug that is chemically related to heroin and heavily used is_______.

12.

True or False: Methadone is classified as a narcotic drug, even though it is not derived from opium or morphine. _________

13.

Drugs that cause marked alterations in mood, attitude, thought processes, and perceptions are called ____________.

14.

_______ is the sticky resin extracted from the marijuana plant.

15.

The active ingredient of marijuana largely responsible for its hallucinogenic properties is_______.

16.

True or False: The potency of a marijuana preparation depends on the proportion of the various plant parts in the mixture._______

17.

The marijuana preparation with the highest THC content is ____________.

18.

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LSD is a chemical derivative of _______, a chemical obtained from the ergot fungus that grows on certain grasses and grains.

19.

The drug phencyclidine is often manufactured for the illicit-drug market in _______ laboratories.

20.

True or False: Alcohol depresses the central nervous system. _________

21.

_______ are called “downers” because they depress the central nervous system.

22.

True or False: Phenobarbital is an example of a long-acting barbiturate._______

23.

_______ is a powerful sedative and muscle relaxant that possesses many of the depressant properties of barbiturates.

24.

_______ and _______ drugs are used to relieve anxiety and tension without inducing sleep.

25.

True or False: Huffing volatile solvents stimulates the central nervous system._______

26.

_______ are a group of synthetic drugs that stimulate the central nervous system.

27.

_______ is extracted from the leaf of the coca plant.

28.

Traditionally, cocaine is _______ into the nostrils.

29.

True or False: Cocaine is a powerful central nervous system depressant._______

30.

The two drugs usually associated with drug-facilitated sexual assaults are _______ and_______.

31.

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_______ steroids are designed to promote muscle growth but have harmful side effects.

32.

Federal law establishes _______ schedules of classification for the control of dangerous drugs.

33.

Drugs that have no accepted medical use are placed in schedule _______.

34.

Librium and Valium are listed in schedule _______.

35.

True or False: Color tests are used to identify drugs conclusively._______

36.

The _______ color-test reagent turns purple in the presence of heroin.

37.

The Duquenois-Levine test is a valuable color test for ____________.

38.

The _______ test is a widely used color test for cocaine.

39.

_______ tests tentatively identify drugs by the size and shape of crystals formed when the drug is mixed with specific reagents.

40.

A technique that uses a moving liquid phase and a stationary solid phase to separate mixtures is _______.

41.

True or False: Thin-layer chromatography yields the positive identification of a material._______

42.

The distance between two successive identical points on a wave is known as _______.

43.

The process of separating light into its component colors is called _______.

44.

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True or False: Color is an indication that substances selectively absorb light._______

45.

Visible light and X-rays are only part of the family of known radiation waves known as the _______.

46.

Red light is (higher, lower) in frequency than violet light.

47.

The selective absorption of electromagnetic radiation by materials (can, cannot) be used as an aid for identification.

48.

The pattern of a(n) _______ and _______ absorption spectrum suggest a probable identity of a drug.

49.

An (infrared, ultraviolet) absorption spectrum provides a unique “fingerprint” of a chemical substance.

50.

The study of the absorption of light by chemical substances is known as _______, and the instrument used to measure and record this absorption spectrum is the _________.

51.

A mixture’s components can be separated by the technique of _______, which separates mixtures on the basis of their distribution between a stationary liquid phase and a moving gas phase.

52.

The gas chromatograph, in combination with the _______, can separate the components of a drug mixture and then unequivocally identify each substance present in the mixture.

53.

The technique of_______ exposes molecules to a beam of high-energy electrons in order to fragment them.

54.

True or False: A mass spectrum is normally considered a specific means for identifying a chemical substance. _________

APPLICATION AND CRITICAL THINKING

1.

An individual who has been using a drug for an extended period of time suddenly finds himself unable to secure more of the drug. He acts nervous and irritable and is hyperactive. He seems almost desperate to find more of the drug but

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experiences no sickness, pain, or other outward physical discomfort. Based on his behavior, what drugs might he possibly have been using? Explain your answer.

2.

Following are descriptions of behavior that are characteristic among users of certain classes of drugs. For each description, indicate the class of drug (narcotics, stimulants, and so on) for which the behavior is most characteristic. For each description, also name at least one drug that produces the described effects.

a) Slurred speech, slow reaction time, impaired judgment, reduced coordination b) Intense emotional responses, anxiety, altered sensory perceptions c) Alertness, feelings of strength and confidence, rapid speech and movement, decreased appetite d) Drowsiness, intense feeling of well-being, relief from pain

3.

Following are descriptions of four hypothetical drugs. According to the Controlled Substances Act, under which drug schedule would each substance be classified?

a) This drug has a high potential for psychological dependence, it currently has accepted medical uses in the United States, and the distributor is not required to report to the US Drug Enforcement Administration. b) This drug has medical use in the United States, is not limited by manufacturing quotas, and may be exported without a permit. c) This drug must be stored in a vault or safe, requires separate record keeping, and may be distributed with a prescription. d) This drug may not be imported or exported without a permit, is subject to manufacturing quotas, and currently has no medical use in the United States.

4.

A police officer stops a motorist who is driving erratically and notices a bag of white powder that he suspects is heroin on the front seat of the car. The officer brings the bag to you, a forensic scientist in the local crime lab. Name one screening test that you might perform to determine the presence of heroin. Assuming the powder tests positive for heroin, what should you do next?

5.

The figure below shows a chromatogram of a known mixture of barbiturates. Based on this figure, answer the following questions:

a) What barbiturate detected by the chromatogram had the longest retention time? b) Which barbiturate had the shortest retention time? c) What is the approximate retention time of amobarbital?

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6.

When investigating a warehouse for potentially storing illegal drugs, the police collected a variety of drugs. The drugs were tested with presumptive color tests for determining their possible identity. The test tubes shown in the following figure display the positive color tests. Match the drugs on the right with the color tests on the left and name the test.

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ENDNOTES

1.

Marijuana-A Signal of Misunderstanding. (Washington, DC: US Government Printing Office, 1972), p. 56.

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12 Forensic Toxicology

© Archive Images / Alamy

LEARNING OBJECTIVES

After studying this chapter, you should be able to:

• Explain how alcohol is absorbed into the bloodstream, transported throughout the body, and eliminated by oxidation and excretion. • Understand the process by which alcohol is excreted in the breath via the lungs. • Understand the concepts of infrared and fuel cell breath-testing devices for alcohol testing. • Describe commonly employed field sobriety tests to assess alcohol impairment. • List and contrast laboratory procedures for measuring the concentration of alcohol in the blood. • Relate the precautions necessary to properly preserve blood in order to analyze its alcohol content. • Understand the significance of implied-consent laws and the Schmerber v. California case to traffic enforcement. • Describe techniques that forensic toxicologists use to isolate and identify drugs and poisons. • Appreciate the significance of finding a drug in human tissues and organs as it relates to assessing impairment. • Describe how to coordinate the drug recognition expert (DRE) program with a forensic toxicology

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finding.

WHAT KILLED NAPOLEON?

Napoleon I, emperor of France, was sent into exile on the remote island of St. Helena by the British after his defeat at the Battle of Waterloo in 1815. St. Helena was hot, unsanitary, and rampant with disease. There, Napoleon was confined to a large reconstructed agricultural building known as Longwood House. Boredom and unhealthy living conditions gradually took their toll on Napoleon’s mental and physical state. He began suffering from severe abdominal pains and experienced swelling of the ankles and general weakness of his limbs. From the fall of 1820, Napoleon’s health began to deteriorate rapidly until he died on May 5, 1821. An autopsy concluded the cause of death was stomach cancer.

Because Napoleon died in British captivity, it was inevitable that numerous conspiratorial theories would develop to account for his death. One of the most fascinating inquiries was conducted by a Swedish dentist, Sven Forshufvud, who systematically correlated the clinical symptoms of Napoleon’s last days to those of arsenic poisoning. He published a book in Swedish about this case in 1961 For Forshufvud, the key to unlocking the cause of Napoleon’s death rested with Napoleon’s hair. Forshufvud arranged to have Napoleon’s hair measured for arsenic content by neutron activation analysis and found it consistent with arsenic poisoning. Nevertheless, the cause of Napoleon’s demise is still a matter for debate and speculation. Other Napoleon hairs collected in 1805 and 1814 have also shown high concentrations of arsenic, giving rise to the speculation that Napoleon was innocently exposed to arsenic over a long period of time. Even hair collected from Napoleon’s three sisters show significant levels of arsenic. Some scientists question whether Napoleon even had the clinical symptoms associated with arsenic poisoning. In truth, forensic science may never be able to answer the question, What killed Napoleon?

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