1. 5-1 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein DRUGS Chapter 5

2. 5-2 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

3. 5-3 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

4. 5-4 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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,

5. 5-5 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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).

6. 5-6 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

7. 5-7 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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. video symbolism

8. 5-8 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

9. 5-9 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Opiates - Heroin

10. 5-10 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

11. 5-11 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

12. 5-12 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Krokadil 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. Made of codeine and gasoline. It substitutes for heroin. It is for that reason that the drug, known as the 'poor man's heroin,' is known as 'krokadil,' or 'crocodile.'

13. 5-13 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

14. 5-14 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

15. 5-15 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

16. 5-16 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Marijuana 101 Short term physical effects –Sedation –Blood shot eyes –Increased heart rate –Coughing –Increased appetite –Decreased blood pressure –Bronchitis –Bronchial asthma

17. 5-17 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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?

18. 5-18 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

19. 5-19 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

20. 5-20 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

21. 5-21 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

22. 5-22 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

23. 5-23 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

24. 5-24 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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 ScreeningJob Drug Screening Money Magazine link

25. 5-25 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.psychoactive designer drugcannabis [1] The ingredients contained in these products are mimics or isomers, not copies of THC. [3]THC [3]

26. 5-26 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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

27. 5-27 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

28. 5-28 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

29. 5-29 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

30. 5-30 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

31. 5-31 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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 high- thinking faculties or inducing sleep. Examples: Xanax, Alprazolam, Klonopin, Clonazepam Xanax, Alprazolam Clonazepam Sniffing glues and gasoline has immediate effects such as exhilaration, but impairs judgment and may cause liver, heart, and brain damage, or even death.

32. 5-32 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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. VideoVideo Stimulants are substances taken to increase alertness or activity, followed by a decrease in fatigue and a loss of appetite.

33. 5-33 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Stimulants

34. 5-34 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Meth Users/Victims

35. 5-35 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Stimulants Amphetamine and methamphetamine, often injected intravenously, cause an initial “rush,” followed by an intense feeling of pleasure. Video Video 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.

36. 5-36 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

37. 5-37 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Club Drugs The term club drugs refers to synthetic drugs that are used at nightclubs, bars, and raves (all- night 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 drug- facilitated sexual assault, rape, and robbery.

38. 5-38 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Club Drugs Methylenedioxymethamphetamine, also known as MDMA or Ecstasy, is a synthetic mind- altering 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.

39. 5-39 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

40. 5-40 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

41. 5-41 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Anabolic Steroids Side effects include unpredictable effects on mood and personality, depression, diminished sex drive, halting bone growth, and liver cancer.

42. 5-42 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein DRUG TRAFFIKING The world wide distribution of drugs is a multi-billion dollar business. Link USALinkUSA Heroin mostly comes from Asia

43. 5-43 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Drug Trafficking - Cocaine Cocaine comes primarily from South America where the coca plant grows.

44. 5-44 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Penalties for Trafficking Drugs Schedule / DrugQuantityPenalties Schedule 1 & 2Any amountFirst Offense: < 20 years in jail; <$1M fine. If injury/death: 20 years to life Second Offense: <30 years; <$2M fine. Schedule 3Any amountFirst offense: <10 years in jail; <$500k fine Second offense: <20 years; < $1.5M fine Schedule 4Any amountFirst Offense: <5 years in jail; < $250k fine Second offense: <10 years; < $500k fine Schedule 5Any amountFirst offense: < 1 year in jail; < $100k fine Second offense: <4 years in jail: <$200k fine

45. 5-45 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

46. 5-46 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

47. 5-47 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

48. 5-48 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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 in the confirmational testing.

49. 5-49 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Qualitative vs. Quantitative Another consideration in selecting an analytical technique is the need for either a qualitative or a quantitative determination. Qualitative relates just to the identity of the material and if it is present or not. This is like the urine test you take to see if you are on drugs at all. Quantitative testing is a much more accurate test that requires the determination of the exact structure and amount of a drug.

50. 5-50 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

51. 5-51 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

52. 5-52 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Mass Spectroscopy

53. 5-53 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Infrared Spectroscopy

54. 5-54 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Chromatography Chromatography is a means of separating and tentatively identifying the components of a mixture.

55. 5-55 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

56. 5-56 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein TLC Thin Layer Chromotography uses a solid stationary phase usually coated onto a glass plate and a mobile liquid phase to separate the components of the mixture.

57. 5-57 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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 R f value.

58. 5-58 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

59. 5-59 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

60. 5-60 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein UVand IR Spectrophotometry Different materials always have distinctively different infrared spectra; each IR spectrum is therefore equivalent to a “fingerprint” of that substance.

61. 5-61 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.

62. 5-62 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein Collection and Preservation The field investigator has the responsibility of ensuring that the evidence is properly packaged and labeled for the laboratory. The Chain of Custody must be documented with signatures from the sample origin individual to the lab, to the police / lawyers. Generally common sense is the best guide, keeping in mind that the package must prevent the loss of the contents and/or cross- contamination. Ideally, the sample will be checked for adulteration or contamination to conceal the drug. Common checks will be temperature, pH, salinity, color/appearance.

63. 5-63 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ 07458 FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein 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.