Examples toxicological analysis

This might help to explain why forensic analysts invest a lot of time in the identification or qualitative stage of the analysis. It is not uncommon to find forensic laboratories performing a three-tier assessment of potential controlled substances. This will involve a presumptive test, followed by a chromatographic separation and finally a mass spectral identification. Many of the analyses performed in the forensic environment are focused on what is present in the sample, rather than how much is there. Another example of this might be a paint examination, where it is important to assess the components present in relation to their chemical composition and also layer structure. Toxicological analysis, on the other hand, does require both a qualitative and quantitative assessment of what is present in the sample. 

Application in USA, EU, D Nonclinical safety studies, for example, toxicology and PK studies (ADME), and analysis of body fluids from clinical trials USA Food, pharmaceuticals/drugs, medical devices, veterinary products, cosmetics EU, D Pharmaceuticals/drugs... 

Cronin MTD. The use of cluster significance analysis to identify asymmetric QSAR data sets in toxicology. An example with eye irritation data. SAR QSAR Environ Res 1996 5 167-75. 

It should be noted that there are likely to be some aerosol particle components that are not readily detectable by the techniques in use now. For example, Kao and Friedlander (1995) have suggested that compounds such as H202 and free radicals that may be important toxicologically would have reacted prior to particle analysis and that species formed from such reactions, e.g., sulfate, may be used as markers of their presence. 

Chemists must become familiar with several fields. For example, the ultimate objective of those working on assessing toxic hazards associated with chemicals, which must be to provide a sound body of knowledge underpinned by validated theory, is still some way off (Richardson, 1986). Assessing the probability that a chemical will be toxic to humans is a complex task. In order to make the correct diagnosis in a particular instance, one would need to be an expert in methods of chemical analysis for tiny concentrations, the physical chemistry of the relevant environment, and the pharmacology and toxicology of the substance. 

An example of another approach is DEREK, a pnblicly available expert system designed to assist chemists and toxicologists in predicting toxicological hazards based on analysis of chemical strnctnre (see table 9.1). DEREK differs from other compnter methods for toxicity prediction in that it makes qnalitative rather than qnantitative predictions and does not rely on algebraic or statistical relationships. 

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