Group-type analysis environmental applications

By far the most common type of plasma used for speciation analysis is the inductively coupled plasma (ICP) with mass spectrometry (MS) or atomic emission spectrometry (AES) detection. The performance of the ICP-MS system has been well documented since its development in the early 1980s by the Gray and Houk research groups [14,15], and it is now used for a wide variety of applications such as environmental, clinical, geological, food, and industrial analysis. 

Like the continuous physico-chemical descriptor Z variables, indicators of the presence or absence of certain substructures have also been treated by multiple regression analysis. As modified by Fujita and Ban (Seydel and Schaper, 1979), this group contribution method can be a useful alternative to the LFER approach, if only limited knowledge is available about the relevant molecular properties or no uniform physico-chemical descriptors for the various compounds in the data set are accessible. For activities and properties of compounds that may be attributed to the occurrence of certain substructures in the molecules (e.g. biodegradation section 4.8), Free-Wilson-type substructure models have their major application in environmental sciences. 

Yang and Cheng (2003) have also reported the metal uptake abiUties of macro cyclic diamine derivative of chitosan. The polymer has high metal uptake abilities, and the selectivity property for the metal ions was improved by the incorporation of azacrown ether groups in the chitosan. The selectivity for adsorption of metal ions on polymer was found to be Ag+> Co >Ci. These results reveal that the new type chitosan-crown ethers will have wide ranging applications for the separation and concentration of heavy metal ions in environmental analysis. 

The surfactants currently available for industrial applications can be separated into two groups those that have a natural or renewable origin derived from oil seed crops, animal fats, or trees, and those derived from petroleum distillates. There has been a great deal of debate on the pros and cons of these two types of sourcing. Renewable surfactant feedstocks are often perceived as being better for the environment and should therefore be the first choice for environmentally friendly products. But is that analysis of the simation scientific fact or spiritually pleasing fiction Are renewable chemicals necessarily better for the environment because they are derived from plant and animal fats and oils As with most scientific, political, and social questions, there is no easy answer. 

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