Our experts have unparalleled credentials and are highly accomplished, each having at least one terminal degree (M.D., Ph.D., Pharm. D, J.D. in addition to other graduate degrees)

 

Technology Behind The Toxicology

toxicology co-counselTalking Toxicology with Your Co-Counsel

Having a co-counsel that is not only familiar with toxicology but also with the technology and methodology behind it can be very useful for your case. This is because he or she will be able to identify any irregularities or mistakes in the process. However the average attorney is unfamiliar with the various processes and instruments used for the identification and quantification of drugs and toxins. As you will discover shortly, these can be rather complex.The more knowledgeable your attorney is with regard to these matters, the more assured you can be that justice will be done.

Evidence Collection
Once evidence is collected it is sent off to a forensic laboratory where analysts perform a series of tests in order to complete the analysis report that will be used in court proceedings. The series of tests can be split up into three stages:

1) Weight Test
First the analyst will determine the weight of the material. In many cases such evidence only consists of some residue found on a surface or a stain on a piece of fabric. The analyst therefore needs to determine whether there is sufficient material for further testing. This weight will also need to be recorded in the analysis report.

2) Presumptive Testing or Screening
The second stage of testing determines the general characteristics of the drug or compound and allows analysts to narrow down the types of confirmatory tests that should be done in the third stage. These include:

  • Microscopic analysis: This is used to determine the structure of the material to make an approximate estimation as to what is contained therein.
  • Microcrystalline testing: This involves dissolving the compound in a solution and letting it crystallize. The manner in which it crystallizes will often allow analysts to identify its components.
  • Ultraviolet spectroscopy: Exposing a material to UV light and measuring the way in which it absorbs this light will also give an indication as to the components present in the material.
  • Gas chromatography: This may also provide analysts with an indication as to what a certain compound consists of, but it is more commonly used in confirmatory testing to separate the compound.

3) Confirmatory Testing
Confirmatory testing typically consists of a two-step process. During the first stage the compounds are separated by means of gas chromatography (GC), liquid chromatography (LC), capillary electrophoresis, or wet chemistry. Thereafter instruments such as a mass spectrometer (MS) or infrared spectrometer (IR) are used to identify the individual components which make up the compound. This is done by comparing the chemical signature of each component against reference materials. These processes may also be combined, the most common being gas chromatography/mass spectroscopy (GC/MS). Confirmatory testing can be carried out by several different instruments such as a Gas Chromatograph-Quadrupole Mass Spectrometer (GC-QMS), a GS-Ion Trap MS, Time-of-Flight MS, Fourier Transform Ion Cyclotron Resonance MS, as well as various others. For a more detailed account of these technologies and the science behind them see Modern Instrumental Methods in Forensic Toxicology.

← Go Back

Law + Science = Foresnsics