Toxicology • Definition: Analysis of body fluids or tissues for the presence of 1) controlled substances, 2) common pharmaceuticals and 3) poisons. • What do Toxicologists know? • All about: • drug interactions, metabolism, therapeutic vs. toxic doses, and impairment
Challenges… • Identify 1 in 1000 drugs/poisons needle in a haystack • Find tiny (nanogram to microgram) quantities, through the entire body • Not always looking for exact chemicals …metabolitesare breakdown products Examples: heroin morphine in seconds THC THC-9 in urine
Forensic Toxicology Father of Modern Toxicology… Orfila
Paracelsus"All things are poison and nothing is without poison, only the dose permits something not to be poisonous.” (1530 AD)
Antemortem = before death DUIs BREATH Drug Facilitated Sex.Asslt. BREATH, URINE Workplace Drug Testing BREATH, URINE Parole violations BREATH Post mortem = after death Homicides Suicides Overdose MVA Unexplained death Natural (sometimes) Toxicology…when do we do it ??
Toxicology of Alcohol • Alcohol is absorbed into the blood, via stomach and small intestine • Once absorbed, alcohol is: • Oxidized (oxidation = burned, with O2) in liver • Excreted in breath and urine… AS UNCHANGED PURE ALCOHOL !!
Alcohol in the Circulatory System • Quantity of alcohol in the blood is… …how drunk you are. • Two methods of making this measurement • Measure alcohol in blood • Measure alcohol in breath
Circulation Con’t Ratio of blood alcohol to alveoli air is approximately 2100 to 1 • Means 2100 mL of Breath has the same alcohol as 1mL of Blood
Breathalyzer Con’t • 3 types of breathalyzers • Measure alcohol in different ways • Chemical… alcohol some other chemical • Fuel Cell… alcohol electricity • Infrared (IR) alcohol reflects IR back
Infrared Breath Test uses infrared wavelengths to test for alcohol Fuel Cell Test converts fuel (alcohol) and oxygen into a measurable electric current Infrared and Fuel Cell Breath Tests
Field Sobriety Testing • Two reasons for the field sobriety test: • Assess suspects’ physical impairment • Determine need of evidential (urine) test.
Field Sobriety Tests • Horizontal Gaze Nystagmus • Involuntary eye jerk as eye moves horizontally • Walk and Turn (divided attention tasks) • One-Leg Stand
Horizontal Gase Nystagmus - CLIP http://www.bing.com/videos/search?q=horizontal+gaze+nystagmus+video&view=detail&mid=95C10FAF1ABA03518D1A95C10FAF1ABA03518D1A&first=0&qpvt=horizontal+gaze+nystagmus+video&adlt=strict
At least we don’t live in France, Germany, Ireland, or Japan (0.05%) or especially Sweden (0.02%)! Alcohol and the Law • 1939-1964: intoxicated = 0.15% BAC • 1965: intoxicated = 0.10% BAC • 2003: intoxicated = 0.08% BAC
Drug Testing in the Body • Urine is most common • Immunoassay • Based on antigen-antibody binding specificity • Antibody produced by injecting antigen (drug) into rabbit • Antibodies will bind to drug in urine • Confirmation done w/TLC
False positives in Immunoassays • Poppy seeds and Vicks 44 for opiates • Decongestants for amphetamines • Benadryl and numerous cough syrups for PCP