Ligand natural organic

Rue E. L. and Bruland, K. W. (1995). Complexation of iron (111) by natural organic ligands in the Central North Pacific as determined by a new competitive ligand equilibration/adsorptive cathodic stripping voltammetric method. Mar. Chem. 50,117-138. 

A technique for the determination of free cupric ions in seawater has been described by Sunda and Hanson [332], The method is based on sorption of copper onto Sep-Pak Cis cartridges and internal free cupric ion calibration. Calibration is accomplished by adding cupric ion buffers and EDTA, which competes with natural organic ligands for copper complexation. The method was used to establish that 0-2% of the copper occurs as inorganic species and 98-100% occurs as organic complexes. 

Xue, H.-B. and Sigg, L. (1998). Cd speciation and complexation by natural organic ligands in freshwater, Anal. Chim. Acta, 363, 249-259. 

In this case, permeability depends only on factors that are outside the organism. Such a scenario might occur in an eutrophic lake where metal speciation is controlled by natural organic ligands forming inert complexes. 

Bioaccumulation is a complicated process that couples numerous complex and interacting factors. In order to directly relate the chemical speciation of an element to its bioavailability in natural waters, it will be necessary to first improve our mechanistic understanding of the uptake process from mass transport reactions in solution to element transfer across the biological membrane. In addition, the role(s) of complex lability and mobility, the presence of competing metal concentrations and the role(s) of natural organic ligands will need to be examined quantitatively and mechanistically. The preceding chapter... 

Speciation of transition metals by natural organic substances that behave as complexing ligands may occur in the subsurface following waste and sludge disposal. As a result, metal solubility increases, favoring metal mobility with depth. 

Van den Berg, C.M.G., 1982. Determination of copper complexation with natural organic ligands in seawater by equilibration with Mn02- II. Experimental procedures and application to surface seawater. Mar. Chem., 11 323-342. 

Gledhill, M., and C. M. G. Van den Berg. 1994. Determination of complexation of iron(III) with natural organic complexing ligands in seawater using cathodic stripping voltammetry. Marine Chemistry 47 41—54. 

Bruland, K.W. (1989) Complexation of zinc by natural organic ligands in the central North Pacific. Limnol. Oceanogr., 34, 269-285. 

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