Forensic Toxicology Essay

1. What are the three areas covered by forensic toxicology? Toxicology covers post-mortem drug testing, workplace drug testing and investigations into contraband materials. 2. Name six specimen types that are often tested in forensic toxicology. Under what circumstances is each specimen preferred? Blood – When testing for DUI’s, and two samples for every death case. Urine – Preemployment drug testing and is preferred over blood as its eacsy to collect large amounts. Bile and liver fluid – Useful for identifying certain types of drugs Hair – Preemployment testing and is advantageous for looking further back in time Oral fluid – Provides the same benefits of urine without invasion of privacy Breath – Used for preliminary test on highways 3. Name the NIDA 5. Draw a table showing the following characteristics of each drug: structure of a representative molecule, drug group, symptoms of overdose and drug source. National Institute on Drug Abuse 5 cites the following drugs 4. Name several groups of medicinal drugs often involved in fatalities. What characteristics render a drug most likely to be associated with overdose deaths? Sedative hynotics, cardioactive agents, antipsychotic agents, antiepileptic drugs and antidepressants. Miss use, or organ damage leading to failure of metabolism. 5. A 210-pound male consumes three highballs each of which was made with 2 ounces of 80 proof whiskey. What is the expected peak in his blood alcohol concentration? His blood alcohol concentration would raise by less than 0.06% as he is larger than an average male. 6. Name three methods for drug screening describe the advantages and disadvantages of each. Name Advantages Disadvantages Immunoassays High sensitivity Not 100% specific Thin Layer Chromatography Can identify hundreds of compounds in one run and is inexpensive Labour intensive and highly technical Ultraviolet-Visible Spectrophotometry Reliable compound recognition Cannot identify less specific features 7. Contrast gas chromatography with and without a mass spectrometer detector. Describe the advantages of the latter technology. Gas chromatography without a mass spectrometer detector relies solely on retention time however the use of a mass spectrometer detector allows for all components of a mixture to be separated. The advantages of mass spectrometer detectors are that it’s often highly unique and provides a fingerprint of the molecule and therefore one can use both the retention time and unique mass spectrum in order to identify substances. 8. What are three methods of metal analysis? Which is the optimal method and why? Three of the methods of metal analysis are colormetric assays, Atomic Absorption Spectrophotometry and neutron activation analysis however inductively coupled plasma-mass spectrometry is the optimal method as it is the most modern and of very high quality. 9. Describe the process of interpreting drug results in the context of preeemployment drug testing. Why is drug testing for employed individuals more difficult? Preemployment drugs test usually use the person in question’s urine, results are interpreted by comparing the level measured to an acceptable baseline. These baselines are not set at 0 because even second hand exposure can lead to trace amounts being metabolised and shown in the urine. Drug testing employed individuals is more difficult as it is usually in the context of confirming that drug abuse was the cause for erratic behaviour, this involves a blood test rather than urine, and further to this there is no agreed level of drug in a system that can be classed as a  Ã¢â‚¬Å"cause† for behaviour. 10. In a published case, an elderly woman with cancer dies. Three fentanyl patches are found on her body. Discuss the investigation of her death with respect to factors that would be significant to the forensic toxicologist in arriving at the cause and manner of death. The patches would be collected as evidence and tested for how much of the active ingredience was still present in the patches and two post mortem blood tests would be taken, one from the heart and one from an extremity, potentially the sites that the patches were applied to would be examined or swabbed also. The main factor in establishing the cause of death would be blood test results.