Artificial trace metals

Chelating agents arc being used in increasing amounts for a number of important purposes. These uses may be put into two important categories first, artificial trace metal carriers and, second, sequestering agents. 

It was generally agreed that any determinations of trace metals carried out on seawater prior to about 1975 are questionable, principally due to the adverse effects of contamination during sampling, which were then little understood and lead to artificially high results. It is only in the past few years that methods of adequate sensitivity have become available for true ultra-trace metal determinations in water. 

R. J. H. Waddell, N. NicDaeid and D. Littlejohn, Classification of ecstasy tablets using trace metal analysis with the application of chemometric procedures and artificial neural networks algorithms. Analyst, 129(3), 2004, 235-240. 

Giusti, L., Yang, Y.-L., Hewitt, C.N., Hamilton-Taylor, J. and Davison, W. (1993) The solubility and partitioning of atmospherically derived trace metals in artificial and natural waters a review. Atmos. Environ., 27A, 1567-1578. 

Artificial liver support systems aim at the extracorporeal removal of water soluble and protein-bound toxins (albumin being the preferential binding protein) associated with hepatic failure. Albumin contains reversible binding sites for substances such as fatty acids, hormones, enzymes, dyes, trace metals and drugs [26] and therefore helps elimination by kidneys of substances that are toxic in the unbound state. It should be noticed that the range of substances to be removed is broad and not completely identified. Clinical studies showed that the critical issue of the clinical syndrome in liver failure is the accumulation of toxins not cleared by the failing liver. Based on this hypothesis, the removal of lipophilic, albumin-bound substances, such as bilirubin, bile adds, metabolites of aromatic amino acids, medium-chain fatty acids, and cytokines, should be benefidal to the dinical course of a patient in liver failure. 

Hamilton-Taylor, J., L. Guisti, W. Davison, W. Tych C. N. Hewitt, 1997. Sorption of trace metals (Cu, Pb, Zn) by suspended lake particles in artificial (0.005 M NaN03) and natural (Esthwaite Water) freshwaters. CoUoids and Surfaces A Physicochemical and Engineering Aspects 120 205-219. 

An overview of the trace-metal, DDE, PCB, hydrocarbon, and artificial radionuclide data. Environ Sci Technol 17 490-496... 

In actual lipid oxidation, one cannot overlook the critical role of trace metals, which complicate the kinetic sequences of initiation and decomposition of lipid hydroperoxides. These metals catalyse both initiation of free radicals and decomposition of hydroperoxides, which become particularly significant with polyunsaturated lipids containing more than two double bonds. With these polyunsaturated lipids, although the yields of hydroperoxides are reduced in the presence of metals, they produce volatile decomposition products that have a serious impact on flavor deterioration. In foods and biological systems, the mixture of trace metals and hydroperoxides is the most important initiator that plays a key part in the development of free radical oxidation and rancidity. The use of artificial azo compounds as initiators to study free radical oxidation is therefore not relevant. 

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