CHEM 107 - Ch. 15 - Forensic Toxicology

field sobriety tests

tests used by law enforcement officers to estimate a motorist's degree of physical impairment by alcohol and determine whether an evidential test for alcohol is justified

gas chromatography

the most widely used approach for determining blood-alcohol levels in a forensic laboratory

screening test

provides the analyst with quick insight into the likelihood that a specimen contains a drug substance

drug recognition expert program

uses standardized methods to examine automobile drivers who are suspected of being under the influence of drugs

detect and identify the presence of drugs and poisons in body fluids, tissues, and organs

what do toxicologists do?

a couple minutes

how long does it take for alcohol to enter the bloodstream once ingested?

absorbed

alcohol slowly increases in concentration while it is being ___ from the stomach at the small intestine into the bloodstream

when all the alcohol has been absorbed and a maximum alcohol level is reached in the blood

when does the post absorption period begin?

the alcohol concentration slowly decreases until a zero level is reached

what happens during post absorption?

through oxidation and excretion

how is elimination of alcohol in the body accomplished?

breath, urine, and perspiration

where is alcohol excreted from?

primarily in the liver

where does oxidation take place?

by measuring the degree of the interaction of the light with alcohol in the captured breath sample

how do breath testers measure blood-alcohol concentration?

that the ratio between the concentration of alcohol in deep-lung or alveolar breath and its concentration in blood is fixed

on what principle do breath-testing devices operate on?

walk and turn and the one leg stand test

what are some examples of field sobriety tests?

devise an analytical scheme to detect, isolate, and specifically identify toxic drug substances extracted from biological fluids, tissues, and organs

what is the goal of the forensic toxicologist?

the results are considered tentative until further confirmation tests ensue

what happens when a screening test comes back positive?

thin-layer chromatography, gas chromatography, immunoassay

what are the most widely used screening tests?

gas chromatography/mass spectrometry

what is accepted as the confirmation test of choice?

a toxicologist may be required to determine the drug's effect on an individual's natural performance or physical state

what happens once a drug is identified in a confirmation test?

a forensic toxicologist

because the DRE program can usually not determine which specific drug was ingested, reliable data from _____ is also required to prove drug intoxication