Toxicology

1
Toxicology

• Drugs and how they are detected
• By Moisey Rafailov
• Instructor Ms. Villani

2
Drugs in the US

• Each year enough drugs are made so that each
  person can have 40 pills.
• Ethyl Alcohol is the most abused drug in the
  Western Hemisphere.

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Alcohol in the body

• After ingestion it goes down the esophagus,
  through the stomach and small intestine and into
  the bloodstream.
• It is then pumped into the heart and the lungs
• It is absorbed by the alveoli and released
  through the nose and mouth.

4
Alcohol In blood and breath

• There is a fixed ratio between the alcohol
  expelled through exhaling and in the blood.
• The ratio is constant at a given temperature
• This ratio allows for breath test instruments to
  be used

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Breathalyzer

• Indirectly determines the quantity of alcohol
  consumed by measuring the absorption of light by
  potassium dichromate
• Last portion of breath is trapped in the machine
  and alcohol level is checked
• Extent of alcohols reaction with KCrO4shows
  blood alcohol level
• Now a portable device used by police

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Alcohols Effect On People

• No specific effect is the same for all people
• Depends on tolerance and size of person
• Detrimental to concentration and motor skills
• "Alcohol selectively suppresses the brain areas
  needed to incorporate new information into
  subsequent and correct motor function."
• This is especially important in motor vehicle
  collisions

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Alcohol Related Car Accidents

• Figures show that 16,000 people were killed in
  the year 2000, due to alcohol related accidents.
  In 2004, that figured climbed to 25,000.
• 500 people die every week and 71 people die
  everyday in alcohol related car accidents.
• For this reason most countries employ legal
  drinking limits

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Alcohol Testing

• By the time a person is taken to a toxicology lab
  or hospital the alcohol will wear off
• Therefore testing is a joint effort made by
  police officers and toxicologists

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Field Sobriety Testing

• The job of the police officer
• To check the impairment of an individual and
  justify an individual test
• Examples are Horizontal gaze nystagmus(eyes
  follow pen or flashlight), walk and turn , and
  the one leg stand (checks balance)
• Used to check for balance, body control and the
  extent of twitching in the eyes.

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Collection and Preservation of Blood

• Job of toxicologist
• Anticoagulants used to prevent clotting
• Preservatives used to protect blood from
  destructive bacteria
• Blood is refrigerated and sodium flouride is
  added to stop bacterial decomposition

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Analysis of Blood for Alcohol

• Job of toxicologist
• Need to know the extent to which alcohol
  metabolizes or breaks down in body
• Two steps in analysis screening (check if drug
  is in body)and confirmation (confirms results)
• Three most common screening tests Thin layer
  chromatography, gas chromatography, and
  immunoassay
• Accepted Confirmation Tests gas
  chromatography/mass spectrophotometry

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Thin Layer Chromatography

• Liquid placed on thin plate
• Liquid slowly rises and begins to separate in
  content
• Dye is applied to allow each liquid to fluoresce
• Level of unknown liquids is compared to known
  liquid of alcohol
• If levels are the same it is most likely alcohol

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Gas Chromatography

• Separates complex mixtures allows for
  identification
• A permanent record is made of the extent of
  separation
• This information is put into a computer that has
  an encyclopedia to detect substances
• Computer makes a graph, the peaks are the points
  tell the concentration

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Immunoassay

• Has the ability to determine small concentrations
  of drugs in body fluids and organs
• Best approach for detecting low drug levels in
  body
• Usually used for marijuana screening

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Significance of Toxicological Findings

• Concentration of alcohol can help determine the
  pharmacological effects on person
• Concentration of blood found in urine is not a
  good indicator because urine occurs outside of
  the circulatory system
• Before determination can be made person must be
  tested for other drugs

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Narcotic Drugs

• Bring relief from pain and produce sleep
• Most common are opium and heroin
• Give a person a high feeling
• Causes physical dependence in user

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Hallucinogens

• Drugs that can cause marked alterations I normal
  thought processes, perceptions and moods.
• Most common is marijuana
• Others are LSD, STP, DMT, and PCP

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Depressants

• Depresses functions of nervous system
• Alcohol
• Barbiturates taken orally and relaxes people,
  it is fatal in large quantities
• Tranquilizers usually induce sleep. Can be given
  to healthy people (Miltown, Librium, Valium).

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Stimulants or Amphetamine

• Stimulate the central nervous system
• Most common is cocaine and its street derivative
  crack
• After use leaves person desperate for more and
  depressed

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Color Tests

• Most drugs react with certain chemicals to
  produce a specific color
• Marquis purple in heroine, opium. Orange brown
  in (meth)amphetamines
• Dilli-Kopanyi violet in barbiturates
• Duquenois-Levine purple for marijuana
• Van Urk blue purple in LSD
• Scott test blue, pink and blue for cocaine

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Microcrystalline tests

• A small drop of a chemical is added to a small
  amount of drug which forms a crystalline
  structure
• Size and shape of crystal can be used to identify
  drug

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Spectrophotometry

• Identifies drug on based on the type of light it
  absorbs
• Infrared spectrophotometry can identify a
  specific drug because infrared spectrum is unique
  for all drugs
• Other types of spectrophotometry are sometimes
  inconclusive

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Identification Of Marijuana

• Because it is a leaf plant it can be identified
  under a microscope
• Under a microscope toxicologists search for hairs
  that look like bear claws on one side and
  nonglandular hairs on other
• When marijuana is in the form of hashish or
  hashish oil a color test is usually used

24
Collection and Preservation of Drug Evidence

• Properly packaged and labeled
• Volatile substances should be placed in an
  airtight container
• If possible investigator should provide
  background information to help identify drug

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Drug Recognition Expert Program

• Program for police officers
• 3-5 month course
• Trains officers to test a person and determine
  the category of drug used
• The final determination is made by the
  toxicologist, but the officers report helps.