Identifying Trace Evidence
Identifying Trace Evidence
Forensic Chemistry and Trace Evidence Analysis
CJ 385
Professor Luckas July 15, 2012
Question 1 In order to identify that a white powder might contain cocaine, a forensic drug chemist can conduct a number of tests. The tests in order to identify cocaine are conducted based on the physical and chemical properties of cocaine. The physical and chemical properties of a substance make it unique, thus identifiable and distinguishable from other physical evidences obtained. One of the physical properties of cocaine is that it is white solid. It may not be identifiable based on its physical properties because they are of generic nature. However, the chemical properties of cocaine may make it easily identifiable among other substances. The chemical property of cocaine is that it is reactive to cobalt thiocyanate and as a result it produces a blue-colored product (Girard, 2007). There are some other substances that also produce the same colored residue with reaction to the chemicals used for substance identification. For example; in reaction to cobalt thiocyanate, a blue-colored product similar to that of cocaine is produced by lidocaine, benzocaine, and procaine. Therefore, the color tests may enable a forensic chemist to do presumptive testing and it cannot be concluded whether the substance is cocaine or any of the other substances. Other tests that can be conducted by conducted by forensic chemists to identify a substance as cocaine are microcrystalline tests. These tests are a special class of drug analysis that produces solid products as a result. The solid products are microscopic crystals that are observed with the help of a microscope with supplied illumination. These tests are usually confirmatory therefore they are more conclusive as compared to color tests. However, the conclusive nature of these tests also depends upon the level of expertise of the forensic chemist. A trained expert shall derive conclusive evidence as
Forensic Chemistry and Trace Evidence Analysis
CJ 385
Professor Luckas July 15, 2012
Question 1 In order to identify that a white powder might contain cocaine, a forensic drug chemist can conduct a number of tests. The tests in order to identify cocaine are conducted based on the physical and chemical properties of cocaine. The physical and chemical properties of a substance make it unique, thus identifiable and distinguishable from other physical evidences obtained. One of the physical properties of cocaine is that it is white solid. It may not be identifiable based on its physical properties because they are of generic nature. However, the chemical properties of cocaine may make it easily identifiable among other substances. The chemical property of cocaine is that it is reactive to cobalt thiocyanate and as a result it produces a blue-colored product (Girard, 2007). There are some other substances that also produce the same colored residue with reaction to the chemicals used for substance identification. For example; in reaction to cobalt thiocyanate, a blue-colored product similar to that of cocaine is produced by lidocaine, benzocaine, and procaine. Therefore, the color tests may enable a forensic chemist to do presumptive testing and it cannot be concluded whether the substance is cocaine or any of the other substances. Other tests that can be conducted by conducted by forensic chemists to identify a substance as cocaine are microcrystalline tests. These tests are a special class of drug analysis that produces solid products as a result. The solid products are microscopic crystals that are observed with the help of a microscope with supplied illumination. These tests are usually confirmatory therefore they are more conclusive as compared to color tests. However, the conclusive nature of these tests also depends upon the level of expertise of the forensic chemist. A trained expert shall derive conclusive evidence as
References: Girard, J.E. (2007). Criminalistics: Forensic Science and Crime. Jones & Bartlett Learning James, S. H., Nordby, J.J. (2005). Forensic Science: An Introduction to Scientific and Investigative Techniques. 2nd Edition. CRC Press Saferstein, R. (2010). Criminalistics: An Introduction to Forensic Science. (10th ed.). Upper Saddle River, NJ: Pearson/ Prentice Hall