Forensic Toxicology
Forensic Toxicology Definition:
Controlled Substances Act Federal Law established 5 schedules of classification of controlled substances based on Drug’s potential for abuse Potential to physical and psychological dependence Medical Value Also controls materials that used in making drugs and those that are manufactured to resemble drugs
Drug Schedules Schedule I: Drugs with high potential for abuse and addiction, NO medical value Ex: Schedule II: Drugs with high potential for abuse and addiction, have some medical value with restrictions
Drug Schedules Schedule III: Drugs with less potential for abuse and addiction, currently acceptable for medical use Ex: Schedule IV: Drugs with low potential for abuse and addiction, currently acceptable for medical use
Drug Schedules Schedule V: Drugs with low potential abuse, medical use, lowest potential dependency Ex:
Role of the Toxicologist Must identify one of thousands of drugs and poisons Must find milligram to gram quantities dissipated throughout the entire body Not always looking for exact chemicals, but metabolites of desired chemicals (ex. heroin morphine within seconds)
Toxicology Procedures 10mL of Add 2 consecutive Some drugs take a while to show up (1-3 days)
Toxicology Procedures color tests, TLC, GC, immunoassay GC-Mass Spec
Color Tests Marquis Test: Scott Test: Three solutions Turns purple in the presence of Heroin, morphine, opium Turns orange-brown in presence of Amphetamines Scott Test: Three solutions Blue then pink then back to blue in the presence of Cocaine Duquenois-Levine: Test for marijuana –turns purple
More Analytical Tests Microcrystalline Tests: Identifies drug by using chemicals that reacts to produce characteristic crystals Chromatography: TLC, HPLC and gas – separate drugs/tentative ID Mass Spectrometry: chemical “fingerprint” no two drugs fragment the same
Why? Think of all the people that you have “heard” do drugs. US drug manufacturers produce enough barbiturates and tranquilizers each year to give every person in the US 40 pills (that’s about 12 billion pills) 18,000 out of 44,000 annual traffic deaths are alcohol related and send over 2 million people to the hospital
Toxicology of Alcohol Alcohol is absorbed through the stomach and intestine Once absorbed, alcohol is:
Factors that Affect Alcohol Absorption
Toxicology of Alcohol Alcohol intoxication depends on
Toxicology of Alcohol Alcohol 1st affects the forebrain and moves backward Last affected is medulla oblongata
Analysis of BAC Field Sobriety Tests Breath Tests Blood Tests
Field Sobriety Tests Horizontal Gaze Nystagmus Walk and Turn Involuntary eye jerk when moving horizontally Walk and Turn One-Leg Stand
Why Breath Tests? The ratio of alcohol in blood to alveolar air is
The Breathalyzer Invented in 1954 by an Indiana state trooper Spectrophotometer designed to measure the absorption of light passing through potassium dichromate
The Breathalyzer 2K2Cr2O7 + 3C2H5OH + 8H2SO4 2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11H2O Indirectly measures alcohol quantity by measuring amount of potassium dichromate Potassium dichromate Ethyl alcohol Sulfuric acid Chromium sulfate Potassium sulfate Acetic acid Dihydrogen oxide
Infrared and Fuel Cell Breath Tests Infrared Breath Test uses infrared wavelengths to test for acetone or other interferences in the breath Fuel Cell Test converts fuel (alcohol) and oxygen into a measurable electric current
Alcohol and the Law 1939-1964: intoxicated = 1965: intoxicated =
Alcohol and the Law Try the drink wheel: http://www.intox.com/wheel/drinkwheel.asp
The End