Forensic Toxicology Toxicology Definition Analysis of body fluids
Forensic Toxicology
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 …metabolites are breakdown products Examples: heroin morphine in seconds 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)
Toxicology…when do we do it ? ? 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 of Alcohol • Alcohol is absorbed into the blood, via stomach and small intestine • Once absorbed, alcohol is: – Oxidized (oxidation = burned, with O 2) 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 m. L of Breath has the same alcohol as 1 m. L of Blood
The Breathalyzer
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 and Fuel Cell Breath Tests • Infrared Breath Test uses infrared wavelengths to test for alcohol • Fuel Cell Test converts fuel (alcohol) and oxygen into a measurable electric current
Field Sobriety Testing • Two reasons for the field sobriety test: 1. Assess suspects’ physical impairment 2. 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=95 C 10 FAF 1 ABA 0 3518 D 1 A 95 C 10 FAF 1 ABA 03518 D 1 A &first=0&qpvt=horizontal+gaze+nyst agmus+video&adlt=strict
Alcohol and the Law • 1939 -1964: intoxicated = 0. 15% BAC • 1965: intoxicated = 0. 10% BAC • 2003: intoxicated = 0. 08% BAC At least we don’t live in France, Germany, Ireland, or Japan (0. 05%) or especially Sweden (0. 02%)!
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
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