Pablo Escobar, Drug LordIn 1989, Forbes magazine listed PabloEscobar as the seventh richest man in theworld. Escobar began his climb to wealthas a teenage car thief in the streets ofMedellin, Colombia, and eventually movedinto the cocaine-smuggling business. Atthe peak of his power in the mid-1980s, hewas shipping as much as eleven tons ofcocaine per flight in jetliners to the UnitedStates. Law enforcement officials estimatethat the Medellin cartel controlled 80percent of the world’s cocaine market andwas taking in about $25 billion annually.

Escobar ruthlessly ruled by the gun:murdering, assassinating, andkidnapping. He was responsible forkilling three presidential candidates inColombia, as well as the storming of theColombian Supreme Court, whichresulted in the murder of half the justices.All the while, Escobar curried favor withthe Colombian general public by

cultivating a Robin Hood image anddistributing money to the poor.

In 1991, hoping to avoid extradition tothe United States, Escobar turned himselfin to the Colombian government andagreed to be sent to prison. However, theprison compound could easily be mistakenfor a country club. There he continued hishigh-flying lifestyle, trafficking bytelephone and even murdering a fewassociates. When the Colombiangovernment attempted to move Escobar toanother jail, he escaped, again fearingextradition to the United States.

Pressured by the U.S. government,Colombia organized a task force dedicatedto apprehending Escobar. The manhuntfor Escobar ended on December 2, 1993,when he was cornered on the roof of oneof his hideouts. A shootout ensued andEscobar was fatally wounded by a bulletbehind his ear.

Key Terms

anabolic steroids

analgesic

chromatography

confirmation

depressant

fluoresce

hallucinogen

infrared

ion

microcrystalline test

monochromatic light

monochromator

narcotic

physical dependence

psychological dependence

screening test

spectrophotometry

stimulant

ultraviolet

150 CHAPTER 5

A drug can be defined as a natural or synthetic substance that is used toproduce physiological or psychological effects in humans or other animals.However, criminalists are concerned primarily with a small number ofdrugs—many of them illicit—that are commonly used for their intoxicatingeffects. These include marijuana, the most widely used illicit drug in theUnited States, and alcohol, which is consumed regularly by 90 millionAmericans. Drug abuse has grown from a problem generally associatedwith members of the lower end of the socioeconomic ladder to one thatcuts across all social and ethnic classes of society. Today, approximately23 million people in the United States use illicit drugs.

Because of the epidemic proportions of illegal drug use, more than75 percent of the evidence evaluated by crime laboratories in the UnitedStates is drug related (see Figure 5–1). The deluge of drug specimens hasforced the expansion of existing crime laboratories and the creation of newones. For many concerned forensic scientists,the crime laboratory’s pre-occupation with drug evidence represents a serious distraction from timethat could be devoted to evaluating evidence related to homicidesand other types of serious crimes. However, the increasing caseloadsassociated with drug evidence have justified the expansion of forensic lab-oratory services. This expansion has increased the overall analyticalcapabilities of crime laboratories.

Drug DependenceIn assessing the potential danger of drugs, society has become particu-larly conscious of their effects on human behavior. In fact, the firstdrugs to be regulated by law in the early years of the twentieth centurywere those deemed to have “habit-forming” properties. The early lawswere aimed primarily at controlling opium and its derivatives, cocaine,and later marijuana. The ability of a drug to induce dependence afterrepeated use is submerged in a complex array of physiological and socialfactors.

Dependence on drugs exists in numerous patterns and in all degreesof intensity, depending on the nature of the drug, the route of adminis-tration, the dose, the frequency of administration, and the individual’srate of metabolism. Furthermore, nondrug factors play an equally

■ Compare and contrast psychological and physicaldependence

■ Name and classify the commonly abused drugs

■ Describe the laboratory tests normally used to performa routine drug identification analysis

■ Describe and explain the process of chromatography

■ Explain the difference between thin-layerchromatography and gas chromatography

■ Describe the utility of ultraviolet and infraredspectroscopy for the identification of organiccompounds

■ Describe the concept and utility of mass spectrometryfor identification analysis

■ Understand the proper collection and preservation ofdrug evidence

Learning ObjectivesAfter studying this chapter you should be able to:

physical dependencePhysiological need for a drug

brought about by its regular

use and characterized by

withdrawal sickness when

administration of the drug is

abruptly stopped.

psychologicaldependenceThe conditioned use of a drug

caused by underlying

emotional needs.

Drugs 151

FIGURE 5–1 Drug bust.Courtesy SyracuseNewspapers/The Image Works

crucial role in determining the behavioral patterns associated with druguse. The personal characteristics of the user, his or her expectationsabout the drug experience, society’s attitudes and possible responses,and the setting in which the drug is used are all major determinants ofdrug dependence.

The question of how to define and measure a drug’s influence on the in-dividual and its danger to society is difficult to assess. The nature and sig-nificance of drug dependence must be considered from two overlappingpoints of view: the interaction of the drug with the individual, and the drug’simpact on society. It will be useful to approach the problem from two dis-tinctly different aspects of human behavior—psychological dependenceand physical dependence.

Psychological DependenceThe common denominator that characterizes all types of repeated drug useis the creation of a psychological dependence for continued use of thedrug. It is important to discard the unrealistic image that all drug users arehopeless “addicts” who are social dropouts. Most users present quite anormal appearance and remain both socially and economically integratedin the life of the community.

The reasons why some people abstain from drugs while othersbecome moderately or heavily involved are difficult if not impossible to

152 CHAPTER 5

FIGURE 5–2 Young peopledrinking. Courtesy DaytonaBeach News-Journal/Jim Tiller

delineate. Psychological needs arise from numerous personal and socialfactors that inevitably stem from the individual’s desire to create a senseof well-being and to escape from reality. In some cases, the individual mayseek relief from personal problems or stressful situations, or may be try-ing to sustain a physical and emotional state that permits an improvedlevel of performance. Whatever the reasons, the underlying psychologicalneeds and the desire to fulfill them create a conditioned pattern of drugabuse (see Figure 5–2).

The intensity of the psychological dependence associated with a drug’suse is difficult to define and largely, depends on the nature of the drugused. For drugs such as alcohol, heroin, amphetamines, barbiturates, andcocaine, continued use will likely result in a high degree of involvement.Other drugs, such as marijuana and codeine, appear to have a consider-ably lower potential for the development of psychological dependence.However, this does not imply that repeated abuse of drugs deemed to havea low potential for psychological dependence is safe or will always producelow psychological dependence. We have no precise way to measure or pre-dict the impact of drug abuse on the individual. Even if a system could bedevised for controlling the many possible variables affecting a user’sresponse, the unpredictability of the human personality would still have tobe considered.

Our general knowledge of alcohol consumption should warn us of thefallacy of generalizing when attempting to describe the danger of drugabuse. Obviously, not all alcohol drinkers are psychologically addicted tothe drug; most are “social” drinkers who drink in reasonable amountsand on an irregular basis. Many people have progressed beyond thisstage and consider alcohol a necessary crutch for dealing with life’sstresses and anxieties. However, a wide range of behavioral patterns exists

Drugs 153

among alcohol abusers, and to a large extent the determination of thedegree of psychological dependence must be made on an individual ba-sis. Likewise, it would be fallacious to generalize that all users of mari-juana can at worst develop a low degree of dependence on the drug. Awide range of factors also influence marijuana’s effect, and heavy usersof the drug expose themselves to the danger of developing a high degreeof psychological dependence.

Physical DependenceAlthough emotional well-being is the primary motive leading to repeatedand intensive use of a drug, certain drugs, taken in sufficient dose and fre-quency, can produce physiological changes that encourage their contin-ued use. Once the user abstains from such a drug, severe physical illnessfollows. The desire to avoid this withdrawal sickness, or abstinence syn-drome, ultimately causes physical dependence, or addiction. Hence, for theaddict who is accustomed to receiving large doses of heroin, the thoughtof abstaining and encountering body chills, vomiting, stomach cramps,convulsions, insomnia, pain, and hallucinations is a powerful inducementfor continued drug use.

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

Physical dependence develops only when the drug user adheres to aregular schedule of drug intake; that is, the interval between doses mustbe short enough so that the effects of the drug never wear off completely.For example, the interval between injections of heroin for the drugaddict probably does not exceed six to eight hours. Beyond this timethe addict begins to experience the uncomfortable symptoms of with-drawal. Many users of heroin avoid taking the drug on a regular basisfor fear of becoming physically addicted to its use. Similarly, the risk ofdeveloping physical dependence on alcohol becomes greatest when theconsumption is characterized by a continuing pattern of daily use inlarge quantities.

Table 5–1 categorizes some of the more commonly abused drugs ac-cording to their effect on the body and summarizes their tendency to pro-duce psychological dependence and to induce physical dependence withrepeated use.

Societal Aspects of Drug UseThe social impact of drug dependence is directly related to the extent towhich the user has become preoccupied with the drug. Here, the most im-portant element is the extent to which drug use has become interwoven inthe fabric of the user’s life. The more frequently the drug satisfies the per-son’s need, the greater the likelihood that he or she will become preoccu-pied with its use, with a consequent neglect of individual and socialresponsibilities. Personal health, economic relationships, and family oblig-ations may all suffer as the drug-seeking behavior increases in frequencyand intensity and dominates the individual’s life. The extreme of drug

154 CHAPTER 5

Table 5–1 The Potential of Some Commonly Abused Drugs to Produce Dependence with Regular Use

Psychological Physical

Drug Dependence Dependence

NarcoticsMorphine High Yes

Heroin High Yes

Methadone High Yes

Codeine Low Yes

DepressantsBarbiturates (short-acting) High Yes

Barbiturates (long-acting) Low Yes

Alcohol High Yes

Methaqualone (Quaalude) High Yes

Meprobamate (Miltown, Equanil) Moderate Yes

Diazepam (Valium) Moderate Yes

Chlordiazepoxide (Librium) Moderate Yes

StimulantsAmphetamines High ?

Cocaine High No

Caffeine Low No

Nicotine High Yes

HallucinogensMarijuana Low No

LSD Low No

Phencyclidine (PCP) High No

dependence may lead to behavior that has serious implications for thepublic’s safety, health, and welfare.

Drug dependence in its broadest sense involves much of the world’spopulation. As a result, a complex array of individual, social, cultural, legal,and medical factors ultimately influence society’s decision to prohibit orimpose strict controls on a drug’s distribution and use. Invariably, societymust weigh the beneficial aspects of the drug against the ultimateharm its abuse will do to the individual and to society as a whole. Obvi-ously, many forms of drug dependence do not carry sufficient adverse so-cial consequences to warrant their prohibition, as illustrated by thewidespread use of such drug-containing substances as tobacco andcoffee. Although the heavy and prolonged use of these drugs may even-tually damage body organs and injure an individual’s health, there is noevidence that they result in antisocial behavior, even with prolonged orexcessive use. Hence, society is willing to accept the widespread use ofthese substances.

We are certainly all aware of the disastrous failure in the United Statesto prohibit the use of alcohol during the 1920s and the current debate onwhether marijuana should be legalized. Each of these issues emphasizesthe delicate balance between individual desires and needs and society’sconcern with the consequences of drug abuse; moreover, this balance iscontinuously subject to change and reevaluation.

narcoticA drug that induces sleep and

depresses vital body functions

such as blood pressure, pulse

rate, and breathing rate.

Drugs 155

Key Points

• A drug is a natural or synthetic substance that is used to produce phys-iological or psychological effects in humans or other animals.

• Nondrug factors that play a part in drug dependence include the per-sonal characteristics of the user, his or her expectations about the drugexperience, society’s attitudes and possible responses, and the settingin which the drug is used.

• Physical dependence is defined as the physiological need for a drugthat has been brought about by its regular use. Psychological depen-dence is the conditioned use of a drug caused by underlying emotionalneeds.

Types of DrugsNarcotic DrugsThe term narcotic is derived from the Greek word narkotikos, meaningnumbness or deadening. Although pharmacologists classify narcoticdrugs as substances that relieve pain and produce sleep, the term narcotichas become popularly associated with any drug that is socially unaccept-able. As a consequence of this incorrect usage, many drugs are improperlycalled narcotics.

This confusion has produced legal definitions that differ from the phar-macological actions of many drugs. For example, until the early 1970s,most drug laws in the United States incorrectly designated marijuana as anarcotic. Even today, federal law classifies cocaine as a narcotic drug, al-though pharmacologically, cocaine is actually a powerful central nervoussystem stimulant, possessing properties opposite those normally associ-ated with the depressant effects of a narcotic.

Opiates Medical professionals apply the term opiate to most of thedrugs properly classified as narcotics. Opiates behave pharmacologi-cally like morphine, a painkiller derived from opium—a gummy, milkyjuice exuded through a cut made in the unripe pod of the Asian poppy(Papaver somniferium). Although morphine is readily extracted fromopium, the most commonly used opium-based drug is heroin, which isproduced by reacting morphine with acetic anhydride or acetyl chloride(see Figure 5–3). Heroin’s high solubility in water makes its street prepa-ration for intravenous administration rather simple, for only by injectionare heroin’s effects felt almost instantaneously and with maximumsensitivity. To prepare the drug for injection, the addict frequently dis-solves it in a small quantity of water in a spoon. The process can bespeeded up by heating the spoon over a candle or several matches. Thesolution is then drawn into a syringe or eyedropper for injection underthe skin (see Figure 5–4).

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

analgesicA substance that lessens or

eliminates pain.

156 CHAPTER 5

FIGURE 5–4 Heroinparaphernalia. Courtesy DrugEnforcement Administration,Washington, D.C.

FIGURE 5–3 The opiumpoppy and its derivatives.Shown are the poppy plant,crude and smoking opium,codeine, heroin, andmorphine. Courtesy DrugEnforcement Administration,Washington, D.C.

Codeine is also present in opium, but it is usually prepared syntheticallyfrom morphine. It is commonly used as a cough suppressant in prescrip-tion cough syrup. Codeine, only one-sixth as strong as morphine, is not anattractive street drug for addicts.

Synthetic Opiates A number of narcotic drugs are not naturally derivedfrom opium. However, because they have similar physiological effects on thebody as the opium narcotics, they are also commonly referred to as opiates.

Methadone is perhaps the best known synthetic opiate. In the 1960s, sci-entists discovered that a person who received periodic doses of methadonewould not get high if he or she then took heroin or morphine. Although

Drugs 157

The content of a typical heroin bag is anexcellent example of the uncertaintyattached to buying illicit drugs. For manyyears into the 1960s and early 1970s,the average bag contained 15 to 20percent heroin. Currently, the averagepurity of heroin obtained in the illicit U.S.market is approximately 35 percent. Theaddict rarely knows or cares whatcomprises the other 65 percent or so of

What’s in That Bag?

Closer Analysis

the material. Traditionally, quinine hasbeen the most common diluent of heroin.Like heroin, it has a bitter taste and wasprobably originally used to obscure theactual potency of a heroin preparationfrom those who wished to taste-test thematerial before buying it. Other diluentscommonly added to heroin are starch,lactose, procaine (Novocain), andmannitol.

methadone is pharmacologically related to heroin, its administration appearsto eliminate the addict’s desire for heroin, with minimal side effects. Thesediscoveries led to the establishment of controversial methadone maintenanceprograms in which heroin addicts receive methadone to reduce or preventfuture heroin use. Physicians increasingly prescribe methadone for pain re-lief. Unfortunately the wide availability of methadone for legitimate medicalpurposes has recently led to greater quantities of the drug being diverted intothe illicit market.

In 1995, the U.S. Food and Drug Administration (FDA) approved foruse the pain-killing drug OxyContin. The active ingredient in OxyContin isoxycodone, a synthetic closely related to morphine and heroin in its chem-ical structure. OxyContin is an analgesic narcotic that has effects similar tothose of heroin. It is prescribed to a million patients for treatment ofchronic pain with doctors writing close to seven million OxyContin pre-scriptions each year. The drug is compounded with a time-release formu-lation that the manufacturer initially believed would reduce the risk ofabuse and addiction. This has not turned out to be the case. It is estimatedthat close to a quarter of a million individuals abuse the drug.

Because it is a legal drug that is diverted from legitimate sources,OxyContin is obtained very differently from illegal drugs. Pharmacy rob-beries, forged prescriptions, and theft of the drug from patients with alegitimate prescription are ways in which abusers access OxyContin. Someabusers visit numerous doctors and receive prescriptions even thoughtheir medical condition may not warrant it.

HallucinogensHallucinogens are drugs that can cause marked alterations in normalthought processes, perceptions, and moods. Perhaps the most popular andcontroversial member of this class of drugs is marijuana.

Marijuana Marijuana is the popular name of the plant Cannabis sativa, aweed that grows wild under most climatic conditions. The Cannabis plantcontains a chemical known as tetrahydrocannabinol, or THC, which pro-duces the psychoactive effects experienced by users. The THC content ofCannabis varies in different parts of the plant. The greatest concentration isusually found in a sticky resin produced by the plant, known as hashish.

hallucinogenA substance that induces

changes in normal thought

processes, perceptions, and

moods.

158 CHAPTER 5

Declining concentrations are typically found in the flowers and leaves, re-spectively. Little THC is found in the stem, roots, or seeds of the plant. Thepotency and resulting effect of the drug fluctuate, depending on the relativeproportion of these plant parts in the marijuana mixture consumedby the user. The most common method of administration is by smokingeither the dried flowers and leaves, or various preparations of hashish (seeFigure 5–5). Marijuana is also occasionally taken orally, typically baked insweets such as brownies or cookies.

Any study of marijuana’s effect on humans must consider the potencyof the marijuana preparation. An interesting insight into the relationshipbetween dosage level and marijuana’s pharmacological effect was pre-sented in the first report of the National Commission on Marijuana andDrug Abuse:

At low, usual “social” doses the user may experience an increasedsense of well-being; initial restlessness and hilarity followed by adreamy, carefree state of relaxation; alteration of sensory percep-tions including expansion of space and time; a more vivid sense oftouch, sight, smell, taste and sound; a feeling of hunger, especiallya craving for sweets; and subtle changes in thought formation andexpression. To an unknowing observer, an individual in this stateof consciousness would not appear noticeably different from hisnormal state.

At higher, moderate doses these same reactions are intensifiedbut the changes in the individual would still be scarcely noticeableto an observer. At very high doses, psychotomimetic phenomenamay be experienced. These include distortion of body image, lossof personal identity, sensory and mental illusions, fantasies andhallucinations.1

FIGURE 5–5 Several rolled marijuana cigarettes lie on a pile of crushed dried marijuanaleaves next to a tobacco cigarette. Courtesy Drug Enforcement Administration, Washington, D.C.

Drugs 159

Marijuana is a weed that grows wild undermost climatic conditions. The plant growsto a height of 5 to 15 feet and ischaracterized by an odd number of leafletson each leaf. Normally each leaf containsfive to nine leaflets, all with serrated orsaw-tooth edges.

The potency of marijuana depends on itsform. Marijuana in the form of loosevegetation has an average THC content ofabout 3–4.5 percent (see Figure 1). Themore potent sinsemilla form averagesabout 6–12 percent in THC content.Sinsemilla is made from the unfertilizedflowering tops of the female Cannabisplants, acquired by removing all maleplants from the growing field at the firstsign of their appearance. Production ofsinsemilla requires a great deal ofattention and care, and the plant istherefore cultivated on small plots.

Marijuana and Hashish

Closer Analysis

Hashish preparations average about 2–8percent THC. On the illicit drug market,hashish usually appears in the form ofcompressed vegetation containing a highpercentage of resin (see Figure 2). Aparticularly potent form of hashish isknown as liquid hashish or hashish oil.Hashish in this form is normally aviscous substance, dark green with atarry consistency. Liquid hashish isproduced by efficiently extracting theTHC-rich resin from the marijuana plantwith an appropriate solvent, such asalcohol. Liquid hashish typically variesbetween 8 and 22 percent in THCcontent. Because of its extraordinarypotency, one drop of the material canproduce a “high.”

FIGURE 2 Blocks of hashish in front ofleaves and flowering tops of the marijuanaplant. Courtesy James King-Holmes, PhotoResearchers, Inc.

FIGURE 1 The marijuana leaf. Courtesy DrugEnforcement Administration, Washington, D.C.

160 CHAPTER 5

Marijuana and its related products havebeen in use legally and illegally for almostthree thousand years. The first referenceto medical use of marijuana is in apharmacy book written about 2737 B.C. bythe Chinese emperor Shen Nung, whorecommended it for “female weakness,gout, rheumatism, malaria, beriberi,constipation and absent-mindedness.” InChina, at that time and even today, themarijuana or hemp plant was also a majorsource of fiber for rope production.Marijuana’s mood-altering powers probablydid not receive wide attention until about1000 B.C., when it became an integral partof Hindu culture in India. After A.D. 500,marijuana began creeping westward, andreferences to it began to appear in Persianand Arabian literature.

The plant was probably brought to Europeby Napoleon’s soldiers when they returnedfrom Egypt in the early nineteenth century.In Europe, the drug excited the interest of

A Brief History of Marijuana

Closer Analysis

many physicians who foresaw itsapplication for treating a wide range ofailments. At this time, it also found someuse as a painkiller and mild sedative. Inlater years, these applications were eitherforgotten or ignored.

Marijuana was first introduced into theUnited States around 1920. The weed wassmuggled by Mexican laborers across theborder into Texas. American soldiers alsobrought the plant in from the ports ofHavana, Tampico, and Veracruz. Althoughits use was confined to a small segment ofthe population, its popularity quicklyspread from the border and Gulf statesinto most major U.S. cities. By 1937, fortysix states and the federal government hadlaws prohibiting the use or possession ofmarijuana. Under most of these laws,marijuana was subject to the samerigorous penalties applicable to morphine,heroin, and cocaine and was oftenerroneously designated a narcotic.

Marijuana easily qualifies as the most widely used illicit drug in theUnited States. For instance, more than 43 million Americans have triedmarijuana, according to the latest surveys, and almost half that numbermay be regular users. In addition to its widespread illegal use, accumulat-ing evidence suggests that marijuana has potential medical uses. Twopromising areas of research are marijuana’s reduction of excessive eyepressure in glaucoma and the lessening of nausea caused by powerful an-ticancer drugs. Marijuana may also be useful as a muscle relaxant.

No current evidence suggests that experimental or intermittent usecauses physical or psychological harm. Marijuana does not cause physicaldependence. However, the risk of harm lies instead in heavy, long-termuse, particularly of the more potent preparations. Heavy users can developa strong psychological dependence on the drug. Some effects of marijuanause include increased heart rate, dry mouth, reddened eyes, impairedmotor skills and concentration, and frequently hunger and an increaseddesire for sweets.

Other Hallucinogens A substantial number of other substances withwidely varying chemical compositions are also used recreationally becauseof their hallucinogenic properties. These include both naturally occurringsubstances such as mescaline and psilocybin and synthetically createddrugs including lysergic acid diethylamide (LSD) and phencyclidine (PCP).

Drugs 161

LSD is synthesized from lysergic acid, a substance derived from ergot,which is a type of fungus that attacks certain grasses and grains. The drugappears in a variety of forms—as a pill, added to a cube of sugar, or ab-sorbed onto a small piece of paper—and is taken orally. Its hallucinogeniceffects were first described by the Swiss chemist Albert Hofmann after heaccidentally ingested some of the material in his laboratory in 1943. LSDproduces marked changes in mood, leading to laughing or crying at theslightest provocation. Feelings of anxiety and tension almost alwaysaccompany LSD use. LSD is very potent; as little as 25 micrograms isenough to start vivid visual hallucinations that can last for about twelvehours. Although physical dependence does not develop with continueduse, the individual user may be prone to flashbacks and psychotic reactionseven after use is discontinued.

Abuse of the hallucinogen phencyclidine, commonly called PCP, has re-cently grown to alarming proportions. Because this drug can be synthe-sized by simple chemical processes, it is manufactured surreptitiously forthe illicit market in so-called clandestine laboratories (see Figure 5–6).These laboratories range from large, sophisticated operations to small labslocated in a garage or bathroom. Small-time operators normally have littleor no training in chemistry and employ “cookbook” methods to synthesizethe drug. Some of the more knowledgeable and experienced operatorshave been able to achieve clandestine production levels that approach acommercial level of operation.

Phencyclidine is often mixed with other drugs, such as LSD or am-phetamine, and is sold as a powder (“angel dust”), capsule, or tablet, or asa liquid sprayed on plant leaves. The drug is smoked, ingested, or sniffed.Following oral intake of moderate doses (1–6 milligrams), the user first ex-periences feelings of strength and invulnerability, along with a dreamysense of detachment. However, the user soon becomes unresponsive, con-fused, and agitated. Depression, irritability, feelings of isolation, audio and

FIGURE 5–6 Scene from a clandestine drug laboratory. Courtesy Drug EnforcementAdministration, Washington, D.C.

depressantA substance that slows down,

or depresses, the functions of

the central nervous system.

162 CHAPTER 5

visual hallucinations, and sometimes paranoia accompany PCP use. Severedepression, tendencies toward violence, and suicide accompany long-termdaily use of the drug. In some cases, the PCP user experiences suddenschizophrenic behavior days after the drug has been taken.

DepressantsDepressants are drugs that slow down, or depress, the central nervous sys-tem. Several types of drugs fall under this category, including the mostwidely used drug in the United States—alcohol.

Alcohol (Ethyl Alcohol) Many people overlook the fact that alcohol is a drug,however, it exerts a powerful depressant action on the central nervoussystem. When alcohol enters the bloodstream, it quickly travels to the brain,where it suppresses the brain’s control of thought processes and musclecoordination. Low doses of alcohol tend to inhibit the mental processesof judgment, memory, and concentration. The drinker’s personality be-comes expansive, and he or she exudes confidence. When taken in moder-ate doses, alcohol reduces coordination substantially, inhibits orderlythought processes and speech patterns, and slows reaction times. Underthese conditions, the ability to walk or drive becomes noticeably impaired.Higher doses of alcohol may cause the user to become highly irritable andemotional; displays of anger and crying are not uncommon. Extremely highdoses may cause an individual to lapse into unconsciousness or even acomatose state that may precede a fatal depression of circulatory and respi-ratory functions. The behavioral patterns of alcohol intoxication vary anddepend partly on such factors as social setting, amount consumed, and thepersonal expectation of the individual with regard to alcohol.

In the United States, the alcohol industry annually produces more thanone billion gallons of spirits, wine, and beer for which 90 million consumers

FIGURE 5–7 Rows of alcohol bottles behind a bar. Courtesy Jeremy Liebman/Stone/GettyImages

Drugs 163

pay nearly $40 billion. Unquestionably, these and other statistics support thefact that alcohol is the most widely used and abused drug (see Figure 5–7).

Barbiturates Barbiturates are derivatives of barbituric acid, a substancefirst synthesized by a German chemist, Adolf Von Bayer, more than a hun-dred years ago. They are commonly referred to as “downers” because theyrelax the user, create a feeling of well-being, and produce sleep. Like alco-hol, barbiturates suppress the vital functions of the central nervous system.Twenty-five barbiturate derivatives are currently used in medical practicein the United States; however, five—amobarbital, secobarbital, phenobar-bital, pentobarbital, and butabarbital—tend to be used for most medicalapplications.

Normally, barbiturate users take these drugs orally. The average seda-tive dose is about 10–70 milligrams. When taken in this fashion, the drugenters the blood through the walls of the small intestine. Some barbiturates,such as phenobarbital, are classified as long-acting barbiturates. They areabsorbed into the bloodstream more slowly than others and thereforeproduce less pronounced effects than faster-acting barbiturates. Theslow action of phenobarbital accounts for its low incidence of abuse. Appar-ently, barbiturate abusers prefer the faster-acting varieties—secobarbital,pentobarbital, and amobarbital.

Since the early 1970s, a nonbarbiturate depressant, methaqualone(Quaalude), has appeared on the illicit-drug scene. Methaqualone is a pow-erful sedative and muscle relaxant that possesses many of the depressantproperties of barbiturates. When taken in prescribed amounts, barbitu-rates are relatively safe, but in instances of extensive and prolonged use,physical dependence can develop.

Antipsychotics and Antianxiety Drugs Although these drugs can be consid-ered depressants, they differ from barbiturates in the extent of their actionson the central nervous system. Generally, these drugs produce a relaxingtranquility without impairing high-thinking faculties or inducing sleep.Antipsychotics such as reserpine and chlorpromazine have been used to re-duce the anxieties and tensions of mental patients. Antianxiety drugs arecommonly prescribed to deal with the everyday tensions of many healthypeople. These drugs include meprobamate (Miltown), chlordiazepoxide(Librium), and diazepam (Valium).

In the past thirty five years, the use of these drugs—particularlyantianxiety drugs—has grown dramatically. Medical evidence shows thatthese drugs produce psychological and physical dependence with re-peated and high levels of usage. For this reason, the widespread prescrib-ing of antianxiety drugs to overcome the pressures and tensions of life hasworried many who fear the creation of a legalized drug culture.

“Huffing” Since the early 1960s, “huffing,” the practice of sniffing materialscontaining volatile solvents (airplane glue or model cement, for example),has grown in popularity. Another dimension has recently been added tothe problem with the increasing number of incidents involving the sniffingof aerosol gas propellants such as freon. All materials abused by huffingcontain volatile or gaseous substances that are primarily central nervoussystem depressants. Although toluene (a solvent used in airplane glue)seems to be the most popular solvent to sniff, others can produce compara-ble physiological effects. These chemicals include naphtha, methyl ethylketone (antifreeze), gasoline, and trichloroethylene (dry-cleaning solvent).

stimulantA substance that speeds up, or

stimulates, the central nervous

system.

164 CHAPTER 5

The usual immediate effects of huffing are a feeling of exhilaration andeuphoria combined with slurred speech, impaired judgment, and double vi-sion. Finally, the user may experience drowsiness and stupor, with these de-pressant effects slowly wearing off as the user returns to a normal state.Most experts believe that users become physiologically dependent on theeffects achieved by huffing. However, little evidence suggests that solventinhalation is addictive. But 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 asfreon and related gases, is accompanied by a significant risk of death.

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

Amphetamines Amphetamines are a group of synthetic stimulants thatshare a similar chemical structure and are commonly referred to in the ter-minology of the drug culture as “uppers” or “speed.” They are typicallytaken either orally or via intravenous injection, and provide a feeling ofwell-being and increased alertness that is followed by a decrease in fatigueand a loss of appetite. However, these apparent benefits of the drug are ac-companied by restlessness and instability or apprehension, and once thestimulant effect wears off, depression may set in.

In the United States, the most serious form of amphetamine abuse stemsfrom intravenous injection of amphetamine or its chemical derivative,methamphetamine (see Figure 5–8). The desire for a more intense amphet-amine experience is the primary motive for this route of administration. Theinitial sensation of a “flash” or “rush,” followed by an intense feeling of plea-sure, constitutes the principal appeal of the intravenous route for the user.During a “speed binge,” the individual may inject amphetamines every twoto three hours. Users have reported experiencing a euphoria that produceshyperactivity, with a feeling of clarity of vision as well as hallucinations.

FIGURE 5–8 Granular amphetaminebeside a razor blade. Courtesy CordeliaMolloy, Photo Researchers, Inc.

Drugs 165

As the effect of the amphetamines wears off, the individual lapses into a pe-riod of exhaustion and may sleep continuously for one or two days. Fol-lowing this, the user often experiences a prolonged period of severedepression, lasting from days to weeks.

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

Cocaine Between 1884 and 1887, pioneering psychologist Sigmund Freudcreated something of a sensation in European medical circles by describinghis experiments with a new drug. He reported a substance of seeminglylimitless potential as a source of “exhilaration and lasting euphoria” thatpermitted “intensive mental or physical work [to be] performed without fa-tigue. . . . It is as though the need for food and sleep was completely banished.”

The object of Freud’s enthusiasm was cocaine, a stimulant extractedfrom the leaves of Erythroxylon coca, a plant grown in the Andes mountainsof South America as well as in tropical Asia (see Figure 5–9). Most com-monly, cocaine is sniffed or “snorted” and is absorbed into the body throughthe mucous membranes of the nose, although it is sometimes injected.Cocaine is a powerful stimulant to the central nervous system, and its effectsresemble those caused by amphetamines—namely, increased alertness andvigor, accompanied by suppression of hunger, fatigue, and boredom.Cocaine produces a feeling of euphoria by stimulating a pleasure center inthe base of the brain, in an area connected to nerves that are responsible foremotions. It stimulates this pleasure center to a far greater degree than it

FIGURE 5–9 Coca leaves and illicitforms of cocaine. Courtesy DrugEnforcement Administration,Washington, D.C.

166 CHAPTER 5

would ever normally be stimulated. Some regular users of cocaine reportaccompanying feelings of restlessness, irritability, and anxiety. Cocaine usedchronically or at high doses can have toxic effects. Cocaine-related deathsresult from cardiac arrest or seizures followed by respiratory arrest.

A particularly potent form of cocaine known as “crack” can be pro-duced by mixing cocaine with baking soda and water and then heating theresulting solution. This material is then dried and broken into tiny chunksthat dealers sell as crack “rocks” that are sufficiently volatile to be smoked.The faster the cocaine level rises in the brain, the greater the euphoria, andthe surest way to obtain a fast rise in the brain’s cocaine level is to smokecrack. Inhaling the cocaine vapor delivers the drug to the brain in less thanfifteen seconds—about as fast as injecting it and much faster than snortingit. The dark side of crack, however, is that the euphoria fades quickly as co-caine levels drop, leaving the user feeling depressed, anxious, and plea-sureless. The desire to return to a euphoric feeling is so intense that crackusers quickly develop a habit for the drug that is almost impossible to over-come. Only a small percentage of crack abusers will ever be cured of thisdrug habit.

In the United States, cocaine abuse is on the rise. Many people areapparently using cocaine to improve their ability to work and to keepgoing when tired. While there is no evidence of physical dependencyaccompanying cocaine’s repeated use, abstention from cocaine afterprolonged use brings on severe bouts of mental depression, which pro-duce a very strong compulsion to resume using the drug. In fact, labo-ratory experiments with animals have demonstrated that of all thecommonly abused drugs, cocaine produces the strongest psychologicalcompulsions for continued use.

The United States spends millions of dollars annually in attempting tocontrol cultivation of the coca leaf in various South American countriesand to prevent cocaine trafficking into the United States. Three-quarters ofthe cocaine smuggled into the United States is refined in clandestine labo-ratories in Colombia. The profits are astronomical. Peruvian farmers maybe paid $200 for enough coca leaves to make one pound of cocaine. The re-fined cocaine is worth $1,000 when it leaves Colombia and sells at retail inthe United States for up to $20,000.

Club DrugsThe term club drugs refers to synthetic drugs that are often used at night-clubs, bars, and raves (all-night dance parties). Substances that are used asclub drugs include, but are not limited to, MDMA (Ecstasy, see Figure 5–10),GHB (gamma hydroxybutyrate), Rohypnol (“Roofies”), ketamine, andmethamphetamine. These drugs have become popular at the dance scene asa way to stimulate the rave experience. A high incidence of use has beenfound among teens and young adults.

GHB and Rohypnol are central nervous system depressants that are of-ten connected with drug-facilitated sexual assault, rape, and robbery. Ef-fects accompanying the use of GHB include dizziness, sedation, headache,and nausea. Recreational users have reported euphoria, relaxation, disin-hibition, and increased libido (sex drive). Rohypnol causes muscle relax-ation, loss of consciousness, and an inability to remember what happenedduring the hours after ingesting the drug. This is particularly a concern ina sexual assault because victims are physically unable to resist the attack.Unsuspecting victims become drowsy or dizzy. Effects are even strongerwhen the drug is combined with alcohol because the user experiencesmemory loss, blackouts, and disinhibition. Drugs such as Rohypnol and

Drugs 167

GHB are odorless, colorless, and tasteless, and thus remain undetectedwhen slipped into a drink.

Methylenedioxymethamphetamine, also known as MDMA or Ecstasy,is a synthetic, mind-altering drug that exhibits many hallucinogenic andamphetamine-like effects. Ecstasy was originally patented as an appetitesuppressant and was later discovered to induce feelings of happinessand 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 accompanychronic abuse of Ecstasy. In addition, chronic use of Ecstasy leads to seriousdamage 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 asconfusion, severe anxiety, and paranoia. The drug can cause significant in-creases in body temperature from the combination of the drug’s stimulanteffect with the often hot, crowded atmosphere of a rave club.

Ketamine is primarily used in veterinary medicine as an animal anes-thetic. When used by humans, the drug can cause euphoria and feelings ofunreality accompanied by visual hallucinations. Ketamine can also causeimpaired motor function, high blood pressure, amnesia, and mild respira-tory depression.

Anabolic SteroidsAnabolic steroids are synthetic compounds that are chemically related tothe male sex hormone testosterone. Testosterone has two different effects onthe body. It promotes the development of secondary male characteristics(androgenic effects), and it accelerates muscle growth (anabolic effects). Ef-forts to promote muscle growth and to minimize the hormone’s androgeniceffects have led to the synthesis of numerous anabolic steroids. However, asteroid free of the accompanying harmful side effects of an androgen drughas not yet been developed.

FIGURE 5–10 Ecstasy, a popular club drug. Courtesy Rusty Kennedy, AP Wide World Photos

anabolic steroidsSynthetic compounds

chemically related to the male

sex hormone testosterone that

are used to promote muscle

growth.

168 CHAPTER 5

Incidence of steroid abuse first received widespread public attentionwhen both amateur and professional athletes were discovered using thesesubstances to enhance their performance. Interestingly, current researchon male athletes given anabolic steroids has generally found little or, atbest, marginal evidence of enhanced strength or performance. While thefull extent of anabolic steroid abuse by the general public is not fullyknown, the U.S. government is sufficiently concerned to regulate the avail-ability of these drugs to the general population and to severely punish in-dividuals for illegal possession and distribution of anabolic steroids. In1991, anabolic steroids were classified as controlled dangerous sub-stances, and the Drug Enforcement Administration was given enforce-ment power to prevent their illegal use and distribution.

Anabolic steroids are usually taken by individuals who are unfamiliarwith the harmful medical side effects. Liver cancer and other liver mal-functions have been linked to steroid use. These drugs also cause mas-culinizing effects in females, infertility, and diminished sex drive in males.For teenagers, anabolic steroids result in premature halting of bonegrowth. Anabolic steroids can also cause unpredictable effects on moodand personality, leading to unprovoked acts of anger and destructive be-havior. Depression is also a frequent side effect of anabolic steroid abuse.

Key Points

• Narcotic drugs are analgesics, meaning they relieve pain by depressingthe central nervous system.

• The most common source for narcotic drugs is opium. Morphine is ex-tracted from opium and used to synthesize heroin.

• Opiates are not derived from opium or morphine, but they have thesame physiological effects on the body. Examples of opiates includemethadone and OxyContin (oxycodone).

• Hallucinogens cause marked changes in normal thought processes,perceptions, and moods. Marijuana is the most well-known drug in thisclass. Other hallucinogens include LSD, mescaline, PCP, psilocybin,and MDMA (Ecstasy).

• Depressants decrease the activity of the central nervous system, calmirritability and excitability, and produce sleep. Depressants include al-cohol (ethanol), barbiturates, tranquilizers, and various substances thatcan be sniffed, such as airplane glue or model cement.

• Stimulants increase the activity of the central nervous system and aretaken to increase alertness and activity. Stimulants include ampheta-mines, sometimes known as “uppers” or “speed,” and cocaine, whichin its freebase form is known as crack.

• Club drugs are synthetic drugs that are used at nightclubs, bars, andraves (all-night dance parties). Some club drugs act as stimulants; oth-ers have depressant effects.

• Anabolic steroids are synthetic compounds that are chemically related tothe male sex hormone testosterone. Anabolic steroids are often abusedby individuals who are interested in accelerating muscle growth.

Drugs 169

Drug-Control LawsThe provisions of drug laws are of particular interest to the criminalist, forthey may impose specific analytical requirements on drug analysis. For ex-ample, the severity of a penalty associated with the manufacture, distribu-tion, possession, and use of a drug may depend on the weight of the drugor its concentration in a mixture. In such cases, the chemist’s report mustcontain all information that is needed to properly charge a suspect underthe provisions of the existing law.

The provisions of any drug-control law are an outgrowth of nationaland local law enforcement requirements and customs, as well as the resultof moral and political philosophies. These factors have produced a widespectrum of national and local drug-control laws. Although their detaileddiscussion is beyond the intended scope of this book, a brief description ofthe U.S. federal law known as the Controlled Substances Act will illustratea legal drug classification system that has been created to prevent and con-trol drug abuse. Many states have modeled their own drug-control laws af-ter this act, an important step in establishing uniform drug-control lawsthroughout the United States.

The federal law establishes five schedulesof classification for controlled dangeroussubstances on the basis of a drug’spotential for abuse, potential for physicaland psychological dependence, andmedical value. This classification system isextremely flexible in that the U.S. attorneygeneral has the authority to add, delete, orreschedule a drug as more informationbecomes available.

Schedule I. Schedule I drugs have a highpotential for abuse, have no currentlyaccepted medical use in the UnitedStates, and/or lack accepted safety foruse in treatment under medicalsupervision. Drugs controlled underthis schedule include heroin,marijuana, methaqualone, and LSD.

Schedule II. Schedule II drugs have a highpotential for abuse, a currentlyaccepted medical use or a medical usewith severe restrictions, and a potentialfor severe psychological or physicaldependence. Schedule II drugs includeopium and its derivatives not listed inschedule I, cocaine, methadone,

Controlled Substances Act

Closer Analysis

phencyclidine (PCP), mostamphetamine preparations, and mostbarbiturate preparations containingamobarbital, secobarbital, andpentobarbital. Dronabinol, the syntheticequivalent of the active ingredient inmarijuana, has been placed inschedule II in recognition of its growingmedical uses in treating glaucoma andchemotherapy patients.

Schedule III. Schedule III drugs have lesspotential for abuse than those inschedules I and II, a currently acceptedmedical use in the United States, anda potential for low or moderate physicaldependence or high psychologicaldependence. Schedule III controls,among other substances, allbarbiturate preparations (exceptphenobarbital) not covered underschedule II and certain codeinepreparations. Anabolic steroids wereadded to this schedule in 1991.

Schedule IV. Schedule IV drugs have a lowpotential for abuse relative to scheduleIII drugs and have a current medical

(continued )

170 CHAPTER 5

Table 5–2 Control Mechanisms of the Controlled Substances Act

Record Manufacturing Distribution Dispensing

Schedule Registration Keeping Quotas Restrictions Limits

I Required Separate Yes Order forms Research use onlyII Required Separate Yes Order forms Rx: written; no RefillsIII Required Readily No, but some Records Rx: written or oral;

retrievable drugs limited by required with medical schedule II quotas authorization refills up

to 5 times in 6 monthsIV Required Readily No, but some Records Rx: written or oral; with

retrievable drugs limited by required medical authorizationschedule II quotas refills up to 5 times

in 6 monthsV Required Readily No, but some Records Over-the-counter

retrievable drugs limited by required (Rx drugs limited toschedule II quotas MD’s order) refills up

to 5 times

Source: Drug Enforcement Administration, Washington, D.C.

use in the United States; their abusemay lead to limited dependencerelative to schedule III drugs. Drugscontrolled in this schedule includepropoxyphene (Darvon), phenobarbital,and tranquilizers such as meprobamate(Miltown), diazepam (Valium), andchlordiazepoxide (Librium).

Schedule V. Schedule V drugs must showlow abuse potential, have medical use inthe United States, and have lesspotential for producing dependence thanschedule IV drugs. Schedule V controlscertain opiate drug mixtures that containnonnarcotic medicinal ingredients.

Controlled dangerous substances listed inschedules I and II are subject tomanufacturing quotas set by the attorneygeneral. For example, eight billion dosesof amphetamines were manufactured in theUnited States in 1971. In 1972, productionquotas were established reducingamphetamine production approximately 80percent below 1971 levels.

The criminal penalties for unauthorizedmanufacture, sale, or possession ofcontrolled dangerous substances are

related to the schedules as well. The mostsevere penalties are associated with drugslisted in schedules I and II. For example, fordrugs included in schedules I and II, a firstoffense is punishable by up to twenty yearsin prison and/or a fine of up to $1 millionfor an individual or up to $5 million for otherthan individuals. Table 5–2 summarizes thecontrol mechanisms and penalties for eachschedule of the Controlled Substances Act.

The Controlled Substances Act alsostipulates that an offense involving acontrolled substance analog, a chemicalsubstance substantially similar inchemical structure to a controlledsubstance, triggers penalties as if it werea controlled substance listed inschedule I. This section is designed tocombat the proliferation of so-calleddesigner drugs—substances that arechemically related to some controlleddrugs and are pharmacologically verypotent. These substances aremanufactured by skilled individuals inclandestine laboratories, with theknowledge that their products will not becovered by the schedules of the Controlled

Closer AnalysisControlled Substances Act (continued )

Drugs 171

Import–Export Manufacturer/Distributor Reports Criminal Penalties for Individual

Narcotic Nonnarcotic Security to Drug Enforcement Administration 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 Yes, narcotic 0–5 years/$250,000

storage area No, nonnarcotic

Permit Declaration Secure Manufacturer only, 0–3 years/$250,000

storage area narcotic

No, nonnarcotic

Permit Declaration Secure Manufacturer only, 0–1 year/$100,000

to import; storage area narcotic

declaration No, nonnarcotic

to export

Substances Act. For instance, fentanyl is apowerful narcotic that is commerciallymarketed for medical use and is alsolisted as a controlled dangeroussubstance. This drug is about onehundred times as potent as morphine.A number of substances chemicallyrelated to fentanyl have been synthesizedby underground chemists and sold on thestreet. The first such substanceencountered was sold under the streetname China White. These drugs havebeen responsible for more than a hundredoverdose deaths in California and nearlytwenty deaths in western Pennsylvania. Asdesigner drugs, such as China White, areidentified and linked to drug abuse, theyare placed in appropriate schedules.

The Controlled Substances Act alsoreflects an effort to decrease theprevalence of clandestine drug laboratories

designed to manufacture controlledsubstances. The act regulates themanufacture and distribution of precursors,the chemical compounds used byclandestine drug laboratories to synthesizeabused drugs. Targeted precursorchemicals are listed in the definitionsection of the Controlled Substances Act.Severe penalties are provided for a personwho possesses a listed precursor chemicalwith the intent to manufacture a controlledsubstance or who possesses or distributesa listed chemical knowing, or havingreasonable cause to believe, that the listedchemical will be used to manufacture acontrolled substance. In addition,precursors to PCP, amphetamines, andmethamphetamines are enumeratedspecifically in schedule II, making themsubject to regulation in the same manneras other schedule II substances.

Key Points

• Federal law establishes five schedules of classification for controlleddangerous substances on the basis of a drug’s potential for abuse, po-tential for physical and psychological dependence, and medical value.

confirmationA single test that specifically

identifies a substance.

screening testA preliminary test used to

reduce the number of possible

identities of an unknown

substance.

172 CHAPTER 5

Forensic Drug AnalysisOne only has to look into the evidence vaults of crime laboratories toappreciate the assortment of drug specimens that confront the criminalist.The presence of a huge array of powders, tablets, capsules, vegetablematter, liquids, pipes, cigarettes, cookers, and syringes is testimony to thevitality and sophistication of the illicit-drug market. If outward appearanceis not evidence enough of the difficult analytical chore facing the forensicchemist, consider the complexity of the drug preparations themselves.Usually these contain active drug ingredients of unknown origin and iden-tity, as well as additives—for example, sugar, starch, and quinine—that di-lute their potency and stretch their value on the illicit-drug market. Do notforget that illicit-drug dealers are not hampered by government regula-tions that ensure the quality and consistency of a product.

When a forensic chemist picks up a drug specimen for analysis, he orshe can expect to find just about anything, so all contingencies must beprepared for. The analysis must leave no room for error, because its resultswill have a direct bearing on the process of determining the guilt or inno-cence 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 positiveconclusion is drawn, the chemist must be prepared to support and defendthe validity of the results in a court of law.

Screening and ConfirmationThe challenge or difficulty of forensic drug identification comes in se-lecting analytical procedures that will ensure a specific identification of adrug. Presented with a substance of unknown origin and composition,the forensic chemist must develop a plan of action that will ultimatelyyield the drug’s identity. This plan, or scheme of analysis, is divided intotwo phases.

First, faced with the prospect that the unknown substance may be anyone of a thousand or more commonly encountered drugs, the analyst mustemploy screening tests to reduce these possibilities to a small and man-ageable number. This objective is often accomplished by subjecting the ma-terial to a series of color tests that produce characteristic colors for themore commonly encountered illicit drugs. Even if these tests produce neg-ative results, their value lies in having excluded certain drugs from furtherconsideration.

Once the number of possibilities has been reduced substantially, thesecond phase of the analysis must be devoted to pinpointing and confirm-ing the drug’s identity. In an era in which crime laboratories receive volu-minous quantities of drug evidence, it is impractical to subject a drug to allthe chemical and instrumental tests available. Indeed, it is more realistic tolook on these techniques as constituting a large analytical arsenal. Thechemist, aided by training and experience, must choose tests that will mostconveniently identify a particular drug.

Forensic chemists often use a specific test to identify a drug substanceto the exclusion of all other known chemical substances. A single test thatidentifies a substance is known as a confirmation. The analytical schemesometimes consists of a series of nonspecific or presumptive tests. Eachtest in itself is insufficient to prove the drug’s identity; however, theproper analytical scheme encompasses a combination of test results thatcharacterize one and only one chemical substance—the drug under in-vestigation. Furthermore, experimental evidence must confirm that the

Drugs 173

FIGURE 5–11 A field colortest kit for cocaine. Thesuspect drug is placed inthe plastic pouch. Tubescontaining chemicals arebroken open and the colorof the chemical reaction isoberved. Courtesy Tri-Tech,Inc., Southport, N.C.,www.tritechusa.com

probability of any other substance responding in an identical manner tothe scheme selected is so small as to be beyond any reasonable scientificcertainty.

Another consideration in selecting an analytical technique is the needfor either a qualitative or a quantitative determination. The former relatesjust to the identity of the material, whereas the latter refers to the percent-age combination of the components of a mixture. Hence, a qualitative iden-tification of a powder may reveal the presence of heroin and quinine,whereas a quantitative analysis may conclude the presence of 10 percentheroin and 90 percent quinine.

Obviously, a qualitative identification must precede any attempt atquantitation, for little value is served by attempting to quantitate a mater-ial without first determining its identity. Essentially, a qualitative analysisof a material requires the determination of numerous properties using avariety of analytical techniques. On the other hand, a quantitative mea-surement is usually accomplished by precise measurement of a singleproperty 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 TestsMany drugs yield characteristic colors when brought into contact withspecific chemical reagents. Not only do these tests provide a useful indica-tor of a drug’s presence, but they are also used by investigators in the fieldto examine materials suspected of containing a drug (see Figure 5–11).2

However, color tests are useful for screening purposes only and are nevertaken 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 mor-phine and most opium derivatives. Marquis also becomes orange-brown when mixed with amphetamines and methamphetamines.

2. Dillie-Koppanyi. This is a valuable screening test for barbiturates, inwhose presence the reagent turns violet-blue in color.

microcrystalline testA test that identifies a specific

substance based on the color

and shape of crystals formed

when the substance is mixed

with specific reagents.

174 CHAPTER 5

3. Duquenois-Levine. This is a valuable color test for marijuana, performedby adding a series of chemical solutions, to the suspect vegetation. A pos-itive result is shown by a purple color when chloroform is added.

4. Van Urk. The reagent turns blue-purple in the presence of LSD. How-ever, owing to the extremely small quantities of LSD in illicit prepara-tions, this test is difficult to conduct under field conditions.

5. Scott Test. This is a color test for cocaine. A powder containing cocaineturns a cobalt thiocyanate solution blue. Upon addition of hydrochloricacid, the blue color is transformed to a clear pink color. Upon additionof chloroform, if cocaine is present, the blue color reappears in thechloroform layer.

Key Points

• Analysts use screening tests to determine the identity of drugs presentin a sample. These tests reduce the number of possible drugs to a smalland manageable number.

• A series of color tests produce characteristic colors for the more com-monly encountered illicit drugs. In a microcrystalline test, a drop of achemical reagent added to a small quantity of drug on a microscopeslide produces crystals highly characteristic of a drug.

• After preliminary testing, forensic chemists use more specific tests toidentify a drug substance to the exclusion of all other known chemicalsubstances.

Microcrystalline TestsA technique considerably more specific than color tests is the microcrys-talline test. A drop of a chemical reagent is added to a small quantity ofthe drug on a microscopic slide. After a short time, a chemical reactionensues, producing a crystalline precipitate. The size and shape of thecrystals, under microscope examination, are highly characteristic of thedrug. Crystal tests for cocaine and methamphetamine are illustrated inFigure 5–12.

FIGURE 5–12 (a) A photomicrograph of a cocaine crystal formed in platinum chloride(400×). (b) A photomicrograph of a methamphetamine crystal formed in gold chloride(400×). Courtesy David P. Blackburn, San Bernardino County Sheriff’s Department,San Bernardino, Calif.

(a) (b)

Drugs 175

FIGURE 5–13 Evaporation of a liquid.

Over the years, analysts have developed hundreds of crystal tests tocharacterize the most commonly abused drugs. These tests are rapid andoften do not require the isolation of a drug from its diluents; however, be-cause diluents can sometimes alter or modify the shape of the crystal, theexaminer must develop experience in interpreting the results of the test.

Most color and crystal tests are largely empirical—that is, scientists donot fully understand why they produce the results that they do. From theforensic chemist’s point of view, this is not important. When the tests areproperly chosen and used in proper combination, their results constitutean analytical scheme that is characteristic for one and only one drug.

ChromatographyChromatography is a means of separating and tentatively identifying thecomponents of a mixture. It is particularly useful for analyzing drug speci-mens, which may be diluted with practically any material in order to increasethe quantity of the product available to prospective customers. The task ofidentifying an illicit-drug preparation would be arduous without the aid ofchromatographic methods to first separate the mixture into its components.

Theory of Chromatography The theory of chromatography is based on thefact that chemical substances tend to partially escape into the surroundingenvironment when dissolved in a liquid or when absorbed on a solid sur-face. For example, if a beaker of water is covered with a bell jar, as shownin Figure 5–13, gas molecules (represented by green balls) escape from thewater into the surrounding enclosed air. The molecules that remain aresaid to be in the liquid phase; the molecules that have escaped into the airare said to be in the gas phase.

As the gas molecules escape into the surrounding air, they accumulateabove the water; random motion carries some of them back into the water.Eventually, a point is reached at which the number of molecules leaving thewater equals the number returning. At this time, the liquid and gas phasesare in equilibrium.

If the temperature of the water is increased, the equilibrium state read-justs itself to a point at which more gas molecules move into the gas phase.

This behavior was first observed in 1803 by British chemist WilliamHenry. His explanation of this phenomenon, known appropriately asHenry’s law, may be stated as follows: When a volatile chemical com-pound is dissolved in a liquid and is brought to equilibrium with air,

chromatographyAny of several analytical

techniques for separating

organic mixtures into their

components by attraction to a

stationary phase while being

propelled by a moving phase.

176 CHAPTER 5

there is a fixed ratio between the concentration of the volatile com-pound in air and its concentration in the liquid, and this ratio re-mains constant for a given temperature.

The distribution of a gas between the liquid and gas phases is determinedby the solubility of the gas; that is, how easily the gas dissolves in the liquid.The higher its solubility, the greater the tendency of the gas molecules to re-main in the liquid phase. If two different gases are simultaneously dissolvedin the same liquid, each reaches a state of equilibrium with the surroundingair independently of the other. For example, as shown in Figure 5–14, gasA (green balls) and gas B (blue balls) are both dissolved in water. At equilib-rium, gas A has a greater number of molecules dissolved in the water thandoes gas B. This is so because gas A is more soluble in water than gas B.

Thin-Layer Chromatography Thin-layer chromatography (TLC) uses a solidstationary phase and a moving liquid phase to separate the constituents ofa mixture. Thin-layer chromatography is a powerful tool for solving manyof the analytical problems presented to the forensic scientist. The method

FIGURE 5–14 At equilibrium, there are moregas A molecules (green balls) than gas Bmolecules (blue balls) in the liquid phase.

In Figures 5–13 and 5–14, both phases—liquid and gas—were kept stationary; thatis, they were not moving. During achromatographic process, however, this isnot the case. Instead, one phase is alwaysmade to move continuously in onedirection over a stationary or fixed phase.For example, in Figure 5–14,chromatography will occur only when theair is forced to move continuously in onedirection over the water. Because gas B(blue balls) has a greater percentage of itsmolecules in the moving phase than doesgas A (green balls), the molecules of gas Bwill travel over the liquid at a faster pacethan those of gas A. Eventually, when themoving phase has advanced a reasonable

The Chromatographic Process

Closer Analysis

distance, the molecules of gas B willbecome entirely separated from those ofgas A, and the chromatographic processwill be complete. This process isillustrated in Figure 1.

Simply, we can think of chromatography asbeing analogous to a race betweenchemical compounds. At the starting line,all the participating substances are mixedtogether; however, as the race progresses,materials that prefer the moving phaseslowly pull ahead of those substances thatprefer to remain in the stationary phase.Finally, at the end of the race, all theparticipants are separated, each crossingthe finish line at different times.

Drugs 177

The different types of chromatographicsystems are as varied as the number ofstationary and moving-phasecombinations that can be devised.However, two chromatographic

processes—gas chromatography andthin-layer chromatography—are mostapplicable for solving many analyticalproblems in the crime laboratory.

FIGURE 1 In this illustration of chromatography, the molecules represented by the blueballs have a greater affinity for the upper phase and hence will be pushed along at a fasterrate by the moving air. Eventually, the two sets of molecules will seperate from each other,completing the chromatograohic process.

Liquid

phase

Liquid phase

Direction

of moving

air

Stationary

liquid

phase

Direction

of moving

air

Stationary

liquid

phase

Direction

of moving

air

Stationary

liquid

phase

(a)

(b)

(c)

is both rapid and sensitive; moreover, less than 100 micrograms of suspectmaterial are required for the analysis. In addition, the equipment necessaryfor TLC work has minimal cost and space requirements. Importantly, nu-merous samples can be analyzed simultaneously on one thin-layer plate.This technique is principally used to detect and identify components incomplex mixtures.

Theory of thin-layer chromatography In TLC, the components of asuspect mixture are separated as they travel up a glass plate, eventually ap-pearing as a series of dark or colored spots on the plate. This action is thencompared to a standard sample separation of a specific drug, such asheroin. If both the standard and the suspect substance travel the same

178 CHAPTER 5

FIGURE 5–15 Chromatograms of known heroin(1) and quinine (2) standards alongside suspectsample (3).

distance up the plate, they can tentatively be identified as being producedby the same substance.

Figure 5–15 shows a sample suspected of containing heroin and quininethat has been chromatographed alongside known heroin and quinine stan-dards. The distance the unknown material migrated up the suspect plate iscompared to the distances that heroin and quinine migrated up a standardsample plate. If the distances are the same, a tentative identification can bemade. However, such an identification cannot be considered definitive, fornumerous other substances can migrate the same distance up the platewhen chromatographed under similar conditions. Thus, thin-layer chro-matography alone cannot provide an absolute identification; it must be usedin conjunction with other testing procedures to prove absolute identity.

TLC in practice. A thin-layer plate is prepared by coating a glass plateor plastic backing with a thin film of a granular material, usually silica gelor aluminum oxide. This granular material serves as the solid stationaryphase and is usually held in place on the plate with a binding agent such asplaster of Paris. If the sample to be analyzed is a solid, it must first be dis-solved in a suitable solvent and a few microliters of the solution spottedwith a capillary tube onto the granular surface near the lower edge of theplate. A liquid sample may be applied directly to the plate in the same man-ner. The plate is then placed upright into a closed chamber that contains aselected liquid, with care that the liquid does not touch the sample spot.

Drugs 179

The liquid slowly rises up the plate by capillary action. This rising liq-uid is the moving phase in thin-layer chromatography. As the liquid movespast the sample spot, the components of the sample become distributedbetween the stationary solid phase and the moving liquid phase. The com-ponents with the greatest affinity for the moving phase travel up the platefaster than those that have greater affinity for the stationary phase. Whenthe liquid front has moved a sufficient distance (usually 10 cm), the devel-opment is complete, and the plate is removed from the chamber and dried(see Figure 5–16). An example of the chromatographic separation of ink isshown in Figure 5–17.

Because most compounds are colorless, no separation will be noticedafter development unless the materials are visualized. To accomplishthis, the plates are placed under ultraviolet light, revealing fluorescent ma-terials (those that emit visible light when exposed to light of a shorterwavelength) as bright spots on a dark background. When a fluorescent dyehas been incorporated into the solid phase, nonfluorescent substances

Sample

spot

Very thin coating of

silica gel or

aluminum oxide

(a)

(b)

Rising solvent; original

spot has separated

into several spots

FIGURE 5–16 (a) In thin-layer chromatography, a liquid sample is spotted onto thegranular surface of a gel-coated plate. (b) The plate is placed into a closed chamber thatcontains a liquid. As the liquid rises up the plate, the components of the sample distributethemselves between the coating and the moving liquid. The mixture is separated, withsubstances with a greater affinity for the moving liquid traveling up the plate at a fasterspeed.

fluoresceTo emit visible light when

exposed to light of a shorter

wavelength—that is, ultraviolet

light.

180 CHAPTER 5

appear as dark spots against a fluorescent background when exposed tothe ultraviolet light. In a second method of visualization, the plate is sprayedwith a chemical reagent that reacts with the separated substances andcauses them to form colored spots. Figure 5–18 shows the chromatogramof a marijuana extract that has been separated into its components by TLCand visualized by having been sprayed with a chemical reagent.

The distance a spot has traveled up a thin-layer plate can be assigned anumerical value known as the Rf value. This value is defined as the distancetraveled by the component divided by the distance traveled by the moving

FIGURE 5–17 (a) The liquid phase begins to move up the stationary phase. (b) Liquidmoves past the ink spot carrying the ink components up the stationary phase. (c) Themoving liquid has separated the ink into its several components.

(a) (b) (c)

FIGURE 5–18 Thin-layer chromatogram of amarijuana extract. Courtesy Sirchie Finger PrintLaboratories, Inc., Youngsville, N.C., www.sirchie.com

Drugs 181

liquid phase. For example, in Figure 5–15 the moving phase traveled10 centimeters up the plate before the plate was removed from the tank.After visualization, the heroin spot moved 8 centimeters, for an Rf value of0.8; the quinine migrated 4 centimeters, for an Rf value of 0.4.

Gas Chromatography (GC) Gas chromatography (GC) separates mixturesbased on their distribution between a stationary liquid phase and a mov-ing gas phase. In gas chromatography, the moving phase is called thecarrier gas, which flows through a column constructed of stainless steel orglass. The stationary phase is a thin film of liquid within the column.

Two types of columns used: the packed column and the capillary col-umn. With the packed column, the stationary phase is a thin film of liquidfixed onto small granular particles packed into the column. This column,usually constructed of stainless steel or glass, is 2 to 6 meters long andabout 3 millimeters in diameter. Capillary columns are composed of glassand are much longer than packed columns—15 to 60 meters in length.These types of columns are very narrow, ranging from 0.25 to 0.75 mil-limeter in diameter. Capillary columns can be made narrower than packedcolumns because their stationary liquid phase is actually coated as a verythin film directly onto the column’s inner wall.

As the carrier gas flows through the packed or capillary column,it carries with it the components of a mixture that have been injectedinto the column. Components with a greater affinity for the movinggas phase travel through the column more quickly than those with agreater affinity for the stationary liquid phase. Eventually, after the mix-ture has traversed the length of the column, it emerges separated intoits components.

The time required for a component to emerge from the column fromthe time of its injection into the column is known as the retention time,which is a useful identifying characteristic of a material. Figure 5–20(a)shows the chromatogram of two barbiturates; each barbiturate has tenta-tively been identified by comparing its retention time to those of knownbarbiturates, shown in Figure 5–20(b). However, because other substancesmay have comparable retention times under similar chromatographic con-ditions, gas chromatography cannot be considered an absolute means ofidentification. Conclusions derived from this technique must be confirmedby other testing procedures.

Gas chromatography is widely used because of its ability to resolve ahighly complex mixture into its components, usually within minutes. It hasan added advantage in that it is extremely sensitive and can yield quanti-tative results. Gas chromatography has sufficient sensitivity to detect andquantitate materials at the nanogram (0.000000001 gram or 1 � 10�9 gram)level.3

SpectrophotometryThe technique of chromatography is particularly suited for analyzing il-licit drugs, because it can separate a drug from other substances thatmay be present in the drug preparation. However, chromatography hasthe drawback of not being able to specifically identify the material underinvestigation. For this reason, other analytical tools are frequently usedto identify drugs. These include the technique of spectrophotometry,which can identify a substance by exposing it to a specific type of elec-tromagnetic radiation.

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182 CHAPTER 5

A simplified scheme of the gaschromatograph is shown in Figure 5–19.The operation of the instrument can besummed up briefly as follows: The carriergas is fed into the column at a constantrate. The carrier gas is chemically inertand is generally nitrogen or helium. Thesample under investigation is injected as aliquid into a heated injection port with asyringe, where it is immediately vaporizedand swept into the column by the carriergas. The column itself is heated in an ovenin order to keep the sample in a vaporstate as it travels through the column. Inthe column, the components of the sampletravel in the direction of the carrier gasflow at speeds that are determined by theirdistribution between the stationary andmoving phases. If the analyst has selected

The Gas Chromatograph

Closer Analysis

the proper liquid phase and has made thecolumn long enough, the components ofthe sample will be completely separatedas they emerge from the column.

As each component emerges from thecolumn, it enters a detector. One type ofdetector uses a flame to ionize theemerging chemical substance, thusgenerating an electrical signal. The signalis recorded on a strip-chart recorder as afunction of time. This written record of theseparation is called a chromatogram. Agas chromatogram is a plot of the recorderresponse (vertical axis) versus time(horizontal axis). A typical chromatogramshows a series of peaks, each peakcorresponding to one component of themixture.

1

3

2

4

56

7

8

1. Sample

2. Injector

3. Carrier gas

4. Column

5. Detector

6. Power supply

7. Recorder

8. Chromatogram

FIGURE 5–19 Basic gas chromatography. Gas chromatography permits rapid separation ofcomplex mixtures into individual compounds and allows identification and quantitativedetermination of each compound. As shown, a sample is introduced by a syringe (1) into aheated injection chamber (2). A constant stream of nitrogen gas (3) flows through theinjector, carrying the sample into the column (4), which contains a thin film of liquid. Thesample is separated in the column, and the carrier gas and separated components emergefrom the column and enter the detector (5). Signals developed by the detector activate therecorder (7), which makes a permanent record of the separation by tracing a series ofpeaks on the chromatograph (8). The time of elution identifies the component present, andthe peak area identifies the concentration. Courtesy Varian Inc., Palo Alto, Calif.

Drugs 183

0 1 2 3 4 5 6 7 8 9 10 11 12

0 1 2 3 4 5 6 7 8 9 10 11 12

Pentobarbital

Secobarbital

TIME (MINUTES)(a)

Butabarbital

Amobarbital

Pentobarbital

Secobarbital

Phenobarbital

TIME (MINUTES)(b)

FIGURE 5–20 (a) An unknown mixture of barbiturates is identified by comparing itsretention times to (b), a known mixture of barbiturates. Courtesy Varian Inc., Palo Alto, Calif.

Theory of Spectrophotometry We have already observed in the descriptionof color that an object does not absorb all the visible light it is exposed to;instead, it selectively absorbs some frequencies and reflects or transmitsothers. Simlarly, the absorption of other types of electromagnetic radiationby chemical substances is also selective. Selective absorption of a

spectrophotometryAn analytical method for

identifying a substance by its

selective absorption of

different wavelengths of light.

184 CHAPTER 5

substance is measured by an instrument called a spectrophotometer, whichproduces a graph or absorption spectrum that depicts the absorption oflight as a function of wavelength or frequency. The absorption of ultravio-let (UV), visible, and infrared (IR) radiation is particularly applicable forobtaining qualitative data pertaining to the identification of drugs.

Absorption at a single wavelength or frequency of light is not 100 per-cent complete—some radiation is transmitted or reflected by the material.Just how much radiation a substance absorbs is defined by a fundamentalrelationship known as Beer’s law, shown in Equation (5–1):

A � kc (5–1)

Here, A symbolizes the absorption or the quantity of light taken up at a sin-gle frequency, c is the concentration of the absorbing material, and k is aproportionality constant. This relationship shows that the quantity of lightabsorbed at any frequency is directly proportional to the concentration ofthe absorbing species; the more material you have, the more radiation itwill absorb. By defining the relationship between absorbance and concen-tration, Beer’s law permits spectrophotometry to be used as a techniquefor quantification.

Ultraviolet and Visible Spectrophotometry Ultraviolet (UV) and visible spec-trophotometry measure the absorbance of UV and visible light as a functionof wavelength or frequency. For example, the UV absorption spectrum ofheroin shows a maximum absorption band at a wavelength of 278 nanome-ters (see Figure 5–21). This shows that the simplicity of a UV spectrum fa-cilitates its use as a tool for determining a material’s probable identity. Forinstance, a white powder may have a UV spectrum comparable to heroin

ultravioletInvisible long frequencies of

light beyond violet in the

visible spectrum.

Heroin

Abs

orba

nce

250 300 350

Wavelength in nanometers

FIGURE 5–21 Ultraviolet spectrum of heroin.

Drugs 185

Amphetamine

Abs

orba

nce

250 300 350

Wavelength (nanometers)

FIGURE 5–22 Ultraviolet spectrum of amphetamine.

and therefore may be tentatively identified as such. (Fortunately, sugar andstarch, common diluents of heroin, do not absorb UV light.)

This technique, however, does not provide a definitive result; otherdrugs or materials may have a UV absorption spectrum similar to that ofheroin. Nevertheless, UV spectrophotometry is often useful in establishingthe probable identity of a drug. For example, if an unknown substance yieldsa UV spectrum that resembles that of amphetamine (see Figure 5–22), thou-sands of substances are immediately eliminated from consideration, and theanalyst can begin to identify the material from a relatively small number ofpossibilities. A comprehensive collection of UV drug spectra provides anindex that can rapidly be searched in order to tentatively identify a drug or,failing that, at least to exclude certain drugs from consideration.

Infrared Spectrophotometry In contrast to the simplicity of a UV spectrum,absorption in the infrared region provides a far more complex pattern.Figure 5–23 depicts the IR spectra of heroin and secobarbital. Here, the ab-sorption bands are so numerous that each spectrum can provide enoughcharacteristics to identify a substance specifically. Different materials al-ways have distinctively different infrared spectra; each IR spectrum istherefore equivalent to a “fingerprint” of that substance and no other.This technique is one of the few tests available to the forensic scientist thatcan be considered specific in itself for identification. The IR spectra of thou-sands of organic compounds have been collected, indexed, and catalogedas invaluable references for identifying organic substances. The selectiveabsorption of light by drugs in the UV and IR regions of the electromagneticspectrum provides a valuable technique for characterizing drugs.

infraredInvisible short frequencies of

light before red in the visible

spectrum.

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186 CHAPTER 5

0.00

100.00

%T

4000 3500 3000 2500 2000 1500 1000 500Wavenumber cm–1

FIGURE 5–23 (a) Infrared spectrum of heroin. (b) Infrared spectrum of secobarbital.

(a)

(b)

0.00

100.00

%T

4000 3500 3000 2500 2000 1500 1000 500Wavenumber cm–1

Drugs 187

The spectrophotometer measures andrecords the absorption spectrum of achemical. The basic components of asimple spectrophotometer are the sameregardless of whether it is designed tomeasure the absorption of UV, visible, orIR radiation. These components areillustrated diagrammatically in the figure.They include (1) a radiation source, (2) amonochromator or frequency selector,(3) a sample holder, (4) a detector toconvert electromagnetic radiation into anelectrical signal, and (5) a recorder toproduce a record of the signal.

The choice of source varies with the typeof radiation desired. For visible radiation,an ordinary tungsten bulb provides aconvenient source of radiation. In the UVregion, a hydrogen or deuterium dischargelamp is normally used, and a heatedmolded rod containing a mixture of rare-earth oxides is a good source of IR light.

The function of the monochromator is toselect a single wavelength or frequency oflight from the source—monochromaticlight. Some inexpensivespectrophotometers pass the lightthrough colored glass filters to remove allradiation from the beam except for adesired range of wavelengths.

More precise spectrophotometers may usea prism or diffraction grating to disperseradiation into its component wavelengthsor frequencies. A diffraction grating is

The Spectrophotometer

Closer Analysis

made by scratching thousands of parallellines on a transparent surface such asglass. As light passes through the narrowspacings between the lines, it spreads outand produces a spectrum similar to thatformed by a prism. The desired wavelengthis obtained when the dispersed radiation isfocused onto a narrow slit that permitsonly selected wavelengths to pass through.

Most laboratory infrared spectrophotometersuse Fourier transform analysis to measurethe wavelengths of light at which a materialabsorbs in the infrared spectrum. Thisapproach does not use any dispersiveelements that select single wavelengths orfrequencies of light emitted from a source;instead, the heart of a Fourier transforminfrared (FT-IR) spectrometer is theMichelson interferometer. Theinterferometer uses a beam-splitting prismand two mirrors, one movable and onestationary, to direct light toward a sample.As the wavelengths pass through thesample and reach a detector, they are allmeasured simultaneously. A mathematicaloperation, the Fourier transform method, isused to decode the measured signals andrecord the wavelength data. These Fouriercalculations are rapidly carried out by acomputer. In a matter of seconds, acomputer-operated FT-IR instrument canproduce an infrared absorption patterncompatible to one generated by a prisminstrument.

Detector RecorderRadiation source

(a)

Monochromator

Prism disperses radiationinto component wavelengths

Prism

Sample cell

Slit

monochromatorA device for isolating individual

wavelengths or frequencies of

light.

monochromatic lightLight having a single

wavelength or frequency.

(continued)

188 CHAPTER 5

DetectorRadiation source

(b)

Monochromator

Prism

Sample cell

Slit

Recorder

Slit allows only selected wavelengths or frequencies of radiation to pass through

DetectorRadiation source

(c)

Monochromator Sample cell Recorder

Prism Slit

Radiation passes through sample, which absorbs certain frequencies

Detector measuresabsorption of radiationby the sample andconverts the radiationinto an electrical signal

Radiation source

(d)

Monochromator Samplecell

Recorder

Prism Slit

DetectorRadiation source

(e)

Monochromator

Prism

Sample cell

Slit

Recorder

Recorder translates electrical signal into recording of the absorption spectrum

The absorption spectrum of a chemical substance allows spectrophotometry to be used for identification.

Spectrophotometry.

Closer AnalysisThe Spectrophotometer (continued)

Drugs 189

Sample preparation varies with the type ofradiation being studied. Absorption spectrain the UV and visible regions are usuallyobtained from samples that have beendissolved in an appropriate solvent.Because the cells holding the solutionmust be transparent to the light beingmeasured, glass cells are used in thevisible region and quartz cells in theultraviolet region. Practically all substancesabsorb in some region of the IR spectrum,so sampling techniques must be modifiedto measure absorption in this spectralregion; special cells made out of sodiumchloride or potassium bromide arecommonly used because they do notabsorb light over a wide range of the IRportion of the electromagnetic spectrum.

The detector measures the quantity ofradiation that passes through the sample

by converting it to an electrical signal. UVand visible spectrophotometers usephotoelectric tube detectors. A signal isgenerated when the photons strike thetube surface to produce a current that isdirectly proportional to the intensity of thelight transmitted through the sample.When this signal is compared to theintensity of light that is transmitted to thedetector in the absence of an absorbingmaterial, the absorbance of a substancecan be determined at each wavelength orfrequency of light selected. The signal fromthe detection system is then fed into arecorder, which plots absorbance as afunction of wavelength or frequency.Modern spectrophotometers are designedto trace an entire absorption spectrumautomatically.

Mass SpectrometryA previous section discussed the operation of the gas chromatograph. Thisinstrument is one of the most important tools in a crime laboratory. Its abil-ity to separate the components of a complex mixture is unsurpassed. How-ever, gas chromatography has one important drawback— its inability toproduce specific identification. A forensic chemist cannot unequivocally statethe identification of a substance based solely on a retention time as deter-mined by the gas chromatograph. Fortunately, by coupling the gas chro-matograph to a mass spectrometer this problem has largely been overcome.

A mixture’s components are first separated on the gas chromatograph.A direct connection between the gas chromatograph column and the massspectrometer then allows each component to flow into the spectrometer asit emerges from the gas chromatograph. In the mass spectrometer, thematerial enters a high-vacuum chamber where a beam of high-energyelectrons is aimed at the sample molecules. The electrons collide with themolecules, causing them to lose electrons and to acquire a positive charge.These positively charged molecules, or ions, are very unstable or areformed with excess energy and almost instantaneously decompose intonumerous smaller fragments. The fragments then pass through an electricor magnetic field, where they are separated according to their masses. Theunique feature of mass spectrometry is that under carefully controlledconditions, no two substances produce the same fragmentation pattern. Inessence, one can think of this pattern as a “fingerprint” of the substancebeing examined (see Figure 5–24).

ionAn atom or molecule bearing a

positive or negative charge.

The technique thus provides a specific means for identifying a chemicalstructure. It is also sensitive to minute concentrations. Mass spectrometry ismostly widely used to identify drugs; however, further research is expectedto yield significant applications to identifying other types of physical evi-dence. Figure 5–25 illustrates the mass spectra of heroin and cocaine; here,each line represents a fragment of a different mass (actually the ratio of massto charge), and the line height reflects the relative abundance of each frag-ment. Note how different the fragmentation patterns of heroin and cocaineare. Each mass spectrum is unique to each drug and therefore provides aspecific test for identifying that substance.

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 sys-tem provides the ultimate in speed, accuracy, and sensitivity. With theability to record and store in its memory several hundred mass spectra,such a system can detect and identify substances present in only one-millionth-of-a-gram quantities. Furthermore, the computer can be pro-grammed to compare an unknown spectrum against a comprehensivelibrary of mass spectra stored in its memory. The advent of personalcomputers and microcircuitry has made it possible to design mass spec-trometer systems that can fit on a small table. Such a unit is pictured inFigure 5–26. With data obtained from a GC/MS determination, a foren-sic analyst can, with one instrument, separate the components of a com-plex drug mixture and then unequivocally identify each substancepresent in the mixture.

190 CHAPTER 5

D

C

B

A

A

B

C

D

Chromatogram Spectra

Separation Identification

GCMS

FIGURE 5–24 How GC/MS works. Left to right, the sample is separated into itscomponents by the gas chromatograph, and then the components are ionized and identifiedby characteristic fragmentation patterns of the spectra produced by the massspectrometer. Courtesy Agilent Technologies, Inc., Palo Alto, Calif.

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Drugs 191

43

94 146

204215

268

327

369

100 200 300

Mass/charge

(a)

Abu

ndan

ce

42

122 150

182

272

82

303

100 150 300

Mass/charge

(b)

Abu

ndan

ce

25020050

FIGURE 5–25 (a) Mass spectrum of heroin. (b) Mass spectrum of cocaine.

1. Injection port 3. Ion source

4. Quadrupole 6. Data system

5. Detector2. GC column

FIGURE 5–26 A tabletop mass spectrometer. (1) The sample is injected into a heatedinlet port, and a carrier gas sweeps it into the column. (2) The GC column separates themixture into its components. (3) In the ion source, a filament wire emits electrons thatstrike 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 theirmass. (5) The detector counts the fragments passing through the quadrupole. The signal issmall and must be amplified. (6) The data system is responsible for total control of theentire GC/MS system. It detects and measures the abundance of each fragment anddisplays the mass spectrum. Courtesy Agilent Technologies, Inc., Palo Alto, Calif.

192 CHAPTER 5

Research-grade mass spectrometers are found in laboratories as largerfloor-model units (see Figure 5–27).

Key Points

• Chromatography is a means of separating and tentatively identifyingthe components of a mixture.

• TLC uses a solid stationary phase, usually coated onto a glass plate, anda mobile liquid phase to separate the components of the mixture.

• Gas chromatography (GC) separates mixtures on the basis of their dis-tribution between a stationary liquid phase and a mobile gas phase.

• Spectrophotometry is the study of the absorption of light by chemicalsubstances.

• Most forensic laboratories use ultraviolet (UV) and infrared (IR) spec-trophotometers to characterize chemical compounds.

• IR spectrophotometry provides a far more complex pattern than UVspectrophotometry. Because different materials have distinctively dif-ferent infrared spectra, each IR spectrum is equivalent to a “finger-print” of that substance.

• Mass spectrometry characterizes organic molecules by observing theirfragmentation pattern after their collision with a beam of high-energyelectrons.

• Infrared spectrophotometry and mass spectrophotometry typically areused to specifically identify a drug substance.

FIGURE 5–27 A scientistinjecting a sample into aresearch-grade massspectrometer. CourtesyGeoff Tompkinson/SciencePhoto Library

Drugs 193

Collection and Preservation of Drug EvidencePreparation of drug evidence for submission to the crime laboratory isnormally relatively simple, accomplished with minimal precautions in thefield. The field investigator must ensure that the evidence is properly pack-aged and labeled for delivery to the laboratory. Considering the countlessforms and varieties of drug evidence seized, it is not practical to prescribeany single packaging procedure for fulfilling these requirements. Gener-ally, common sense is the best guide in such situations, keeping in mindthat the package must prevent loss and/or cross-contamination of the con-tents. Often, the original container in which the drug was seized will suf-fice to meet these requirements. Specimens suspected of containingvolatile solvents, such as those involved in glue-sniffing cases, must bepackaged in an airtight container to prevent evaporation of the solvent. Allpackages must be marked with sufficient information to ensure identifica-tion by the officer in future legal proceedings and to establish the chain ofcustody.

To aid the drug analyst, the investigator should supply any backgroundinformation that may relate to a drug’s identity. Analysis time can bemarkedly reduced when the chemist has this information. For the samereason, the results of drug-screening tests used in the field must also betransmitted to the laboratory. However, although these tests may indicatethe presence of a drug and may help the officer establish probable causeto search and arrest a suspect, they do not offer conclusive evidence of adrug’s identity.

Chapter SummaryA drug can be defined as a natural or synthetic substance that is used toproduce physiological or psychological effects in humans or other animals.Narcotic drugs are analgesics, meaning they relieve pain by depressing thecentral nervous system. Regular use of a narcotic drug leads to physical de-pendence. The most common source of narcotic drugs is opium. Morphineis readily extracted from opium and is used to synthesize heroin. Opiates,which include methadone and OxyContin (oxycodone), are not derivedfrom opium or morphine, but they have the same physiological effects onthe body as opium narcotics.

Another class of drugs is hallucinogens; marijuana is the most well-known member of this class. Hallucinogens cause marked changes inthought processes, perceptions, and moods. Marijuana is the most contro-versial drug in this class because its long-term effects on health are still

194 CHAPTER 5

largely unknown. Other hallucinogens include LSD, mescaline, PCP, psilo-cybin, and MDMA (Ecstasy).

Depressants are drugs that slow the central nervous system. Theseinclude alcohol (ethanol), barbiturates, tranquilizers, and various substancesthat can be sniffed, such as airplane glue and model cement. Stimulants havethe opposite effect; they increase the activity of the central nervous system.Stimulants include amphetamines, sometimes known as “uppers” or“speed,” and cocaine, which in its freebase form is known as crack.

The term club drugs refers to synthetic drugs that are used at night-clubs, bars, and raves (all-night dance parties). Substances that are of-ten used as club drugs include, but are not limited to, MDMA (Ecstasy),GHB (gamma hydroxybutyrate), Rohypnol (“Roofies”), ketamine, andmethamphetamine.

Anabolic steroids are synthetic compounds that are chemically relatedto the male sex hormone testosterone. Anabolic steroids are often abusedby individuals who want to accelerate muscle growth.

Federal law establishes five schedules of classification for controlleddangerous substances on the basis of a drug’s potential for abuse, poten-tial for physical and psychological dependence, and medical value.

Analysts use screening tests to determine whether a sample containsone or more commonly encountered illicit drugs. These tests include colortests that produce characteristic colors for certain drugs. Once this pre-liminary analysis is completed, a forensic scientist performs a confirmationtest to identify a drug substance to the exclusion of all other known chem-ical substances.

Chromatography, spectrophotometry, and mass spectrometry are allreadily used by forensic scientists to identify illicit drugs. Chromatographyis a means of separating and tentatively identifying the components of amixture. Gas chromatography (GC) separates mixtures based on theirdistribution between a stationary liquid phase and a mobile gas phase.Thin-layer chromatography (TLC) uses a solid stationary phase, usuallycoated onto a glass plate, and a mobile liquid phase to separate the compo-nents of the mixture. Spectrophotometry is the study of the absorption oflight by chemical substances. Mass spectrometry characterizes organicmolecules by observing their fragmentation pattern after their collisionwith a beam of high-energy electrons. By connecting a GC to a mass spec-trometer, the forensic scientist can capture a unique “fingerprint” of thesubstance being examined.

Most forensic laboratories use ultraviolet (UV) or infrared (IR) spec-trophotometers to characterize chemical compounds. Absorption in theinfrared region provides a far more complex pattern than absorption in theUV spectrum. Different materials always have distinctively different in-frared spectra; each IR spectrum is therefore equivalent to a “fingerprint”of that substance.

Drugs 195

Review QuestionsFacts and Concepts

1. What is a drug? How has drug use affected the growth of crime laboratoriesin the United States?

2. Name three nondrug factors that play a part in drug dependence.

3. Define physical dependence and psychological dependence.

4. Physical dependence develops only when the drug user

a. takes large doses of a drug.b. takes one drug to the exclusion of all others.c. uses a drug on a regular schedule.d. has used a drug for at least six months.

5. What is the most important factor to consider when evaluating the social im-pact of drug dependence on an individual?

6. What is the pharmacological definition of a narcotic?

7. What is the source of most narcotic analgesics? Name two popular drugs pre-pared from this substance.

8. Name two synthetic opiates and describe the purpose for which each typicallyis used.

9. What is a hallucinogen? Name three commonly used hallucinogens.

10. What is the most widely used illicit drug in the United States? What is the ac-tive ingredient in this drug?

11. Arrange the following parts or products of the Cannabis plant in order of THCcontent, from highest to lowest concentration of THC: flowers, leaves, resin,seeds, stem.

12. List three potential medical uses of marijuana.

13. What is angel dust and what are the negative consequences of long-term use?

14. What is the most widely abused drug in the United States?

15. In what class of drugs do alcohol and barbiturates belong? What is the mainphysiological effect of such drugs?

16. What is huffing?

17. What is a stimulant? Name two widely used stimulants.

18. Name two potent forms of methamphetamine. How is each of these drugstypically taken into the body?

196 CHAPTER 5

19. What popular stimulant is derived from a plant that grows in the Andesmountains of South America?

20. What is crack and how is it produced?

21. Name club drugs belonging to three different classes of drugs, and indicatethe class to which each belongs.

22. What are anabolic steroids and why were they developed?

23. What are the two phases in a forensic scientist’s analytical scheme?

24. What is the difference between a screening test and a confirmation test?

25. Name two types of empirical tests used to identify drugs. Why are these testsreferred to as empirical?

26. What is the difference between a qualitative evaluation and a quantitativeevaluation?

27. Why is chromatography particularly well suited to the needs of a drug analyst?

28. In chromatography, the distribution of a gas between the liquid and gasphases is determined by

a. the density of the gas relative to the liquid.b. the volume of the gas in the container.c. the solubility of the gas in the liquid.d. the mass of the gas relative to the liquid.

29. Explain how chromatography is like a race between chemical compounds.

30. Name three distinct advantages of gas chromatography in the identificationof drugs.

31. What is the main drawback of gas chromatography in the identification ofdrugs?

32. What phenomenon forms the basis of spectrophotometry?

33. What is the main advantage of infrared spectrophotometry over ultraviolet orvisible-light spectrophotometry?

34. With what analytical device is a gas chromatograph often connected to ana-lyze drug mixtures, and why?

Drugs 197

Application and Critical Thinking1. An individual who has been using a drug for an extended period of time sud-

denly finds himself unable to secure more of the drug. He acts nervous andirritable and is hyperactive. He seems almost desperate to find more of thedrug, but experiences no sickness, pain, or other outward physical discom-fort. 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 ofcertain classes of drugs. For each description, indicate the class of drug (nar-cotics, stimulants, and so on) for which the behavior is most characteristic.For each description, also name at least one drug that produces the describedeffects.

a. slurred speech, slow reaction time, impaired judgment, reduced coordinationb. intense emotional responses, anxiety, altered sensory perceptionsc. alertness, feelings of strength and confidence, rapid speech and move-

ment, decreased appetited. drowsiness, intense feeling of well-being, relief from pain

3. Following are descriptions of four hypothetical drugs. According to the Con-trolled Substances Act, under which drug schedule would each substance beclassified?

a. This drug has a high potential for psychological dependence, it currentlyhas accepted medical uses in the United States, and the distributor is notrequired to report to the U.S. Drug Enforcement Administration.

b. This drug has medical use in the United States, is not limited by manufac-turing quotas, and may be exported without a permit.

c. This drug must be stored in a vault or safe, requires separate record keep-ing, and may be distributed with a prescription.

d. This drug may not be imported or exported without a permit, is subjectto manufacturing quotas, and currently has no medical use in the UnitedStates.

4. A police officer stops a motorist who is driving erratically and notices a bagof white powder on the front seat of the car that he suspects contains heroin.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 presenceof heroin. Assuming the powder tests positive for heroin, what should youdo next?

5. The figure on page 198 shows a chromatogram of a known mixture of barbi-turates. Based on this figure, answer the following questions:

a. What barbiturate detected by the chromatogram had the longest retentiontime?

b. Which barbiturate had the shortest retention time?c. What is the approximate retention time of amobarbital?

198 CHAPTER 5

Web ResourcesDrugs.com (Extensive database of information about the use and effects of 24,000different drugs)www.drugs.com

National Institute on Drug Abuse (Division of the National Institute of Health withlinks to information about effects of and studies about legal and illicit drugs)www.nida.nih.gov

General Alcohol Information (Fact sheet on impact of alcohol use on accidents,injuries, violence, unwanted pregnancy, and other areas of public health and welfare)www.cdc.gov/alcohol/factsheets/general_information.htm

Impaired Driving Facts (Statistics compiled by the National Center for InjuryPrevention and Control)www.cdc.gov/ncipc/factsheets/drving.htm

Neuroscience for Kids (Information about the history, production, use, effects, anddetection of the drugs discussed in the text)faculty.washington.edu/chudler/introb.html#drug

Drugs of Abuse (A publication of the Drug Enforcement Administration decribingillicit drugs)www.dea.gov/pubs/abuse/index.htm

StreetDrugs.org (Extensive information about the history and effects of hundreds ofdifferent legal and illicit drugs)www.streetdrugs.org

Drug Schedules (List of substances classified under each section of the U.S. federalnarcotics laws)www.mspta.com/dre/pdf/Drug_Schedules.pdf

Chromatography (Simple description of chromatographic processes with diagrams)antoine.frostburg.edu/chem/senese/101/matter/chromatography.shtml

0 1 2 3 4 5 6 7 8 9 10 11 12

Butabarbital

Amobarbital

Pentobarbital

Secobarbital

Phenobarbital

TIME (MINUTES)(b)

Drugs 199

Basic Principles of Spectrophotometry (Online simulation of a spectrophotometer)www.chm.davidson.edu/ChemistryApplets/spectrophotometry/Spectrophotometry.html

Beer’s Law (Online experiment applying Beer’s law using spectrophotometersimulation)www.chm.davidson.edu/ChemistryApplets/spectrophotometry/BeersLaw.html

Endnotes1. Marijuana—A Signal of Misunderstanding (Washington, D.C.: U.S. Government

Printing Office, 1972), p. 56.

2. Field-test color kits for drugs can be purchased from various commercialmanufacturers.

3. Powers of 10 are quite useful and simple for handling large or small numbers.The exponent expresses the number of places the decimal point must be moved. Ifit is positive, the decimal point is moved to the right; if it is negative, the decimalpoint is moved to the left. Thus, to express 1 � 10�9 as a number, the decimal pointis simply moved nine places to the left of 1.