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Chapter 5 DRUGS FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-1 Introduction • A DON’T ASK / DON’T TELL POLICY IS IN EFFECT; UNLESS YOU WANT TREATMENT / HELP FROM COUNSELORS. • A drug can be defined as a natural or synthetic substance that is used to produce physiological or psychological effects in humans or other higher order animals. • Narcotic drugs are analgesics, meaning they relieve pain by a depressing action on the central nervous system. This effects functions such as blood pressure, pulse rate and breathing rate. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-2 Drug-Control Laws • The U.S. federal law known as the Controlled Substances Act will serve to illustrate a legal drug-classification system created to prevent and control drug abuse. • This federal law establishes five schedules of classification for controlled dangerous substances on the basis of a drug’s – potential for abuse – potential for physical and psychological dependence – medical value FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-3 Schedules of Classification • Schedule I drugs have a high potential for abuse and have no currently accepted medical use such as heroin, marijuana, methaqualone, crystal meth, K2 and LSD. • Schedule II drugs have a high potential for abuse and have medical use with severe restrictions such as cocaine, PCP, and most amphetamine and barbiturate prescriptions. This includes most ADHD medications, Oxycontin, Fentanyl, Morphine, FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-4 Schedules of Classification • Schedule III drugs have less potential for abuse and a currently accepted medical use such as all barbiturate prescriptions not covered under Schedule II, such as codeine and anabolic steroids. • Schedule IV drugs have a low potential for abuse and have a current medical use such as darvon, phenobarbital, and some tranquilizers such as diazepam (valium) and chlordiazepoxide (librium). FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-5 Schedules of Classification • Schedule V drugs must show low abuse potential and have medical use such as opiate drug mixtures that contain nonnarcotic medicinal ingredients. Codeine cough syrup is an example. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-6 Introduction • The regular use of a narcotic drug will invariably lead to physical dependence. • The most common source for these narcotic drugs is opium, extracted from poppies. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-7 Opiates • Morphine is readily extracted from opium and is used to synthesize heroin. • Addicts frequently dissolve heroin in water by heating it in a spoon, and then inject in the skin or veins. • Heroin produces a “high” that is accompanied by drowsiness and a sense of well-being that generally last for three to four hours. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-8 Opiates - Heroin FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-9 Opiates • Codeine is also present in opium, but it is usually prepared synthetically from morphine. • OxyContin, with the active ingredient oxycodone, is not derived from opium or morphine, but does have the same physiological effects on the body as do opium narcotics. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-10 Other Opiates • OxyContin is prescribed to a million patients for treatment of chronic pain. • Methadone is another well-known synthetic opiate. • Methadone, which is pharmacologically related to heroin, appears to eliminate the addict’s desire for heroin while producing minimal side effects. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-11 Krokadil - Heroin • The Texas DEA tells 1200 WOAI news that it has experienced the first case of a Texan being treated for using a new type of drug which leaves the user with flesh lesions and turns the skin a scaly green color. • It is for that reason that the drug, known as the 'poor man's heroin,' is known as 'krokadil,' or 'crocodile.' FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-12 Hallucinogens • Another class of drugs is hallucinogens; marijuana is the most well-known member of this class. • Hallucinogens cause marked changes in normal thought processes, perceptions, and moods. • Marijuana is the most controversial drug in this class because its long-term effects on health are still largely unknown. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-13 Marijuana • Marijuana refers to a preparation derived from the plant Cannabis. • The chemical substance largely responsible for the hallucinogenic properties of marijuana is known as tetrahydrocannabinol, or THC. • The THC content of Cannabis varies in different parts of the plant, generally decreasing in the following sequence: resin, flowers, leaves, with little THC in the stem, roots or seeds. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-14 Marijuana 101 • •Short term effects – –Problems with memory and learning, distorted perception, and difficulty in thinking and problem-solving – –Loss of coordination – •Impairs driving abilities • •High doses – –Mental confusion, panic reactions and hallucinations FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-15 Marijuana 101 • Short term physical effects – – – – – – – – •Sedation •Blood shot eyes •Increased heart rate •Coughing •Increased appetite •Decreased blood pressure •Bronchitis •Bronchial asthma FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-16 Marijuana • The THC-rich Marijuana does not cause physical dependency, but the risk of harm is in heavy, long-term use to lungs and memory. • Marijuana is a Federal Class I drug (Totally Illegal). Some individual states have legalized it for medical and recreational purposes. Question: Who wins? Feds or State? FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-17 Commercial Medical THC • THC: Available Medications: •Marinol® – –The only drug currently approved by the FDA that contains the synthetic form of THC. Available through prescription in pill form – –Used to: • •Relieve nausea and vomiting associated with chemotherapy for cancer patients • •Assist with loss of appetite in AIDS patients. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-18 THC Medications: Sativex • THC: Available Medications: •Sativex® – –Approved in June 2010 for use in ONLY Canada and UK (NOT USA) – –Oralmucosal spray for treatment of spasticity due to Multiple Sclerosis – •Contains THC and cannabidiol (CBD) – •Grown in a structured and scientific environment. Administers a set dosage • •Reduces the intoxicating effects FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-19 Medical Marijuana in USA • Nov 2, 2010: Arizona Became the 14th State to Legalize Medical Marijuana Alaska Arizona California Colorado Hawaii Maine Michigan Montana Nevada New Mexico Oregon Vermont Rhode Island Washington • FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-20 Medical Example: Arizona • Arizona Medical Marijuana Act: • •Requires registry identification cards • •Limits the number of dispensaries • Includes several requirements for physicians who may provide patients with written prescriptions. • •Requires dispensaries to appoint an individual who is a physician to function as a medical director • •Requires dispensaries to develop, document, and implement policies and procedures regarding inventory control FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-21 Medical Requirements for Pot • Must have one of the following qualifying conditions: – –Cancer, glaucoma, HIV, AIDS, Hepatitis C, Amyotrophic Lateral Sclerosis, Crohn’s disease, Agitation of Alzheimer’s disease, or – –A chronic or debilitating disease or medical condition (or the treatment for) that causes: – •severe and chronic pain, severe nausea, •seizures, severe or persistent muscle spasms or a debilitating medical condition. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-22 Qualifying Patients • •A qualified patient may possess up to 2.5 ounces of usable marijuana in 14 days. – •May not smoke it in public places, including dispensaries – •May eat it in foods or use infused products – •Cannot drive a motor vehicle under the influence – •If eligible to cultivate: may have up to 12 marijuana plants – – – – After the first 16 months since implementation in Arizona: •31,112 Qualifying Patients approved •27% female, 73% male •28 qualifying patients are under 18 yo FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-23 Legal Recreational Pot • Historically the USA has kept Pot illegal. • In 2012 Voters in Washington and Colorado passed ballot initiatives Tuesday to legalize marijuana for recreational use. The Federal Government has not changed its classification of pot yet. It is still • ILLEGAL. Job Drug Screening Money Magazine link FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-24 Synthetic Marijuana • Synthetic cannabis is a psychoactive designer drug created by spraying natural herbs with synthetic chemicals that, when consumed, allegedly mimic the effects of cannabis. It is often known by the brand names K2[1] and Spice. • The ingredients contained in these products are mimics or isomers, not copies of THC.[3] FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-25 Synthetic Marijuana • K2 may trigger a chronic (long-term) psychotic disorder among vulnerable individuals such as those with a family history of mental illness. • Safety of the drug has not been established by studies, but reports of reactions have occurred. • Link news • Video link FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-26 Other Hallucinogens • Other hallucinogens include LSD, mescaline, PCP, psilocybin, and MDMA (Ecstasy). • LSD is synthesized from lysergic acid, a fungus by-product, and can cause hallucinations that can last for 12 hours. You can have sudden “flashbacks” years after a single use. • Phencyclidine, or PCP, is often synthesized in clandestine laboratories and is often smoked, ingested, sniffed. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-27 Other Hallucinogens • Phencyclidine is often mixed with other drugs, such as LSD, or amphetamine, and is sold as a powder (“angel dust”), capsule, or tablet. • Oral intake of PCP first leads to feelings of strength and invulnerability, which may turn to depression, tendencies toward violence, and suicide. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-28 Depressants • Depressants are another class of drugs. • Depressants are substances used to depress the functions of the central nervous system. • Depressants calm irritability and anxiety and may induce sleep. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-29 Depressants • These include alcohol (ethanol), barbiturates, tranquilizers, and various substances that can be sniffed, such as airplane glue, model cement, or aerosol gas propellants such as freon. • Alcohol (ethyl alcohol) enters the body’s bloodstream and quickly travels to the brain, where it acts to suppress the brain’s control of thought processes and muscle coordination. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-30 Depressants • Barbiturates, or “downers,” are normally taken orally and create a feeling of well-being, relax the body, and produce sleep. • Tranquilizers, unlike barbiturates, produce a relaxing tranquility without impairment of highthinking faculties or inducing sleep. • Sniffing has immediate effects such as exhilaration, but impairs judgment and may cause liver, heart, and brain damage, or even death. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-31 Stimulants • The drug classification of stimulants includes amphetamines, sometimes known as “uppers” or “speed,” and cocaine, which in its free-base form is known as crack. • Stimulants are substances taken to increase alertness or activity, followed by a decrease in fatigue and a loss of appetite. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-32 Stimulants FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-33 Stimulants • Amphetamine and methamphetamine, often injected intravenously, cause an initial “rush,” followed by an intense feeling of pleasure. • This is followed by a period of exhaustion and a prolonged period of depression. • Cocaine, extracted from the leaves of Erythroxylin coca, causes increased alertness and vigor, accompanied by the suppression of hunger, fatigue, and boredom. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-34 Stimulants • Crack is cocaine mixed with baking soda and water, then heated. • Crack is often smoked in glass pipes, and like cocaine stimulates the brain’s pleasure center. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-35 Club Drugs • The term club drugs refers to synthetic drugs that are used at nightclubs, bars, and raves (allnight dance parties). • Substances that are often used as club drugs include, but are not limited to, MDMA (Ecstasy), GHB (gamma hydroxybutyrate), Rohypnol (“Roofies”), ketamine, and methamphetamine. • GHB and Rohypnol are central nervous system depressants that are often connected with drugfacilitated sexual assault, rape, and robbery. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-36 Club Drugs • Methylenedioxymethamphetamine, also known as MDMA or Ecstasy, is a synthetic mindaltering drug that exhibits many hallucinogenic and amphetamine-like effects. • Ecstasy enhances self-awareness and decreases inhibitions, however, seizures, muscle breakdown, stroke, kidney failure, and cardiovascular system failure often accompany chronic abuse. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-37 Club Drugs • Ketamine is primarily used as a veterinary animal anesthetic that in humans causes euphoria and hallucinations. • Ketamine can also cause impaired motor functions, high blood pressure, amnesia, and mild respiratory depression. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-38 Anabolic Steroids • Yet another category of drugs is the anabolic steroids. • These are synthetic compounds that are chemically related to the male sex hormone testosterone. • Anabolic steroids are often abused by individuals who are interested in accelerating muscle growth. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-39 Anabolic Steroids • Side effects include unpredictable effects on mood and personality, depression, diminished sex drive, halting bone growth, and liver cancer. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-40 Drug Identification • The challenge or difficulty of forensic drug identification comes in selecting analytical procedures that will ensure a specific identification of a drug. • This plan, or scheme of analysis, is divided into two phases. – Screening test that is nonspecific and preliminary in nature to reduce the possibilities to a manageable number. – Confirmation test that is a single test that specifically identifies a substance. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-41 Preliminary Analysis • Faced with the prospect that the unknown substance may be any one of a thousand or more commonly encountered drugs, the analyst must employ screening tests to reduce these possibilities to a small and manageable number. • This objective is often accomplished by subjecting the material to a series of color tests that will produce characteristic colors for the more commonly encountered illicit drugs. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-42 Preliminary Analysis • Microcrystalline tests can also be used to identify specific drug substances by studying the size and shape of crystals formed when the drug is mixed with specific reagents. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-43 Confirmational Determination • Once this preliminary analysis is completed, a confirmational determination is pursued. • Forensic chemists will employ a specific test to identify a drug substance to the exclusion of all other known chemical substances. • Typically infrared spectrophotometry or gas chromatography-mass spectrometry is used to specifically identify a drug substance. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-44 Mass Spectroscopy FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-45 Infrared Spectroscopy FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-46 Qualitative vs. Quantitative • Another consideration in selecting an analytical technique is the need for either a qualitative or a quantitative determination. • The former relates just to the identity of the material, whereas the latter requires the determination of the percent composition of the components of a mixture. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-47 Chromatography • Chromatography is a means of separating and tentatively identifying the components of a mixture. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-48 Chromatography • The theory of chromatography is based on the observation that chemical substances have a tendency to partially escape into the surrounding environment when dissolved in a liquid or when absorbed on a solid surface. • Those materials that have a preference for the moving phase will slowly pull ahead and separate from those substances that prefer to remain in the stationary phase. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-49 TLC • TLC uses a solid stationary phase usually coated onto a glass plate and a mobile liquid phase to separate the components of the mixture. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-50 TLC • The liquid will slowly rise up the plate by capillary action causing the sample to become distributed between the stationary phase and the moving liquid phase. • Because most compounds are colorless, the materials must be visualized by placing the plates under ultraviolet light or spraying the plate with a chemical reagent. • The distance a spot travels up a thin-layer plate can be assigned a numerical value known as the Rf value. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-51 Gas Chromatography • In GC, the moving phase is actually a gas called the carrier gas, which flows through a column. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-52 Gas Chromatography • The stationary phase is a thin film of liquid contained within the column. • After a mixture has traversed the length of the column, it will emerge separated into its components. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-53 Gas Chromatography • The written record of this separation is called a chromatogram. • The time required for a component to emerge from a GC column is known as retention time. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-54 Spectrohotometry • Just as a substance can absorb visible light to produce color, many of the invisible radiations of the electromagnetic spectrum are likewise absorbed. • Spectrophotometry, an important analytical tool, measures the quantity of radiation that a particular material absorbs as a function of wavelength and frequency. • The quantity of light absorbed at any frequency is directly proportional to the concentration of the absorbing species. This is known as Beer’s Law. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-55 UVand IR Spectrophotometry • Currently, most forensic laboratories use UV and IR spectrophotometers to characterize chemical compounds. • The simplicity of the UV spectrum facilitates its use as a tool for determining a material’s probable identity, although it may not provide a definitive result. • The IR spectrum provides a far more complex pattern. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-56 UVand IR Spectrophotometry • Different materials always have distinctively different infrared spectra; each IR spectrum is therefore equivalent to a “fingerprint” of that substance. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-57 The Spectrophotometer • The spectrophotometer is the instrument used to measure and record the absorption spectrum of a chemical substance. • The components of a spectrophotometer are: – – – – A radiation source A monochromator or frequency selector A sample holder A detector to convert electromagnetic radiation into an electrical signal – A recorder to produce a record of the signal • Absorption spectra can be done in the visible, ultraviolet (UV) or infrared (IR) regions. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-58 Mass Spectrometry • In the mass spectrometer, a beam of high-energy electrons collide with a material, producing positively charged ions. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-59 Mass Spectrometry • These positive ions almost instantaneously decompose into numerous fragments, which are separated according to their masses. • The unique feature of mass spectrometry is that under carefully controlled conditions, no two substances produce the same fragmentation pattern. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-60 GC and Mass • A direct connection between the GC column and the mass spectrometer allows each component to flow into the mass spectrometer as it emerges from the GC. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-61 GC and Mass • The separation of a mixture’s components is first accomplished by the GC. • Then, fragmentation of each component by high-energy electrons in the mass spectrometer, will produce a distinct pattern, somewhat like a “fingerprint”, of the substance being examined. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-62 GC and Mass FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-63 Collection and Preservation • The field investigator has the responsibility of ensuring that the evidence is properly packaged and labeled for the laboratory. • Generally common sense is the best guide, keeping in mind that the package must prevent the loss of the contents and/or crosscontamination. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-64 Collection and Preservation • Often the original container in which the drug was seized will suffice. • All packages must be marked with information that is sufficient to ensure identification by the officer in the future and establish the chain of custody. FORENSIC SCIENCE: An Introduction, 2nd ed. By Richard Saferstein ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 5-65