Zinc speciation metals

Applications EXAFS spectroscopy is obviously well suited to speciate and quantify the state of heavy metals, e.g. in soils [310]. Similarly, it allows differentiation of ZnO and Zn stearate on the basis of the X-ray absorption structure of zinc. 

L. Landner and R. Reuther (eds.) Metals in Society and in the Environment. A Critical Review of Current Knowledge on Fluxes, Speciation, Bioavailability and Risk for Adverse Effects of Copper, Chromium, Nickel and Zinc. 2004... 

Marin A, Lopez-Gonzalvez A, Barbas C. Development and validation of extraction methods for determination of zinc and arsenic speciation in soils using focused ultrasound application to heavy metal study in mud and soils. Anal. Chim. Acta 2001 442 305-318. 

Doe BR (1994) Zinc, copper, and lead in mid-ocean ridge basalts and the source rock control on Zn/Pb in ocean-ridge hydrothermal deposits. Geochim Cosmochim Acta 58 2215-2223 Ehrlich S, Butler I, Halicz L, Rickard D, Oldroyd A, Matthews A (submitted) Experimental study of copper isotope fractionation between aqueous Cu(II) and covellite, CuS. Chem Geol Finney LA, O Halloran TV (2003) Transition metal speciation in the cell insights from the chemistry of metal ion receptors. Science 300 931-936... 

An interesting application of speciation is in the study of changes in the distribution of certain metals after administration of drugs. Falchuk used gel filtration combined with flame atomic absorption spectrometry to study effects of the administration of ACTH on the zinc distribution in serum. Kamel et ai. developed methods to follow the distribution of gold. 

Due to the various health risks of different element species, there are a multitude of applications for natural water samples in this field (e.g., Cr and Sb speciation or Br and I determination).19 The investigation of heavy metal complexes with humic substances by isotope dilution SEC-ICP-MS has been described, for example, by McSheehy and Mester.20 Copper, zinc and molybdenum were found to form complexes with similar size fractions of humic substances in seepage water samples from soils. Sturgeon s group proposed the use of solid phase microextraction (SPME)... 

Komorsky-Lovrfc, S., and M. Branica. 1987. Trace metal speciation by anodic stripping voltammetry. Part VII. Interaction of zinc with chloride, nitrate, sulfate, iodide and hydroxide. J. Electroanal. Chem. 226 253-261. 

Florence, T.M. (1977) Trace metal species in fresh waters. Water Res., 11, 681-687. Florence, T.M. (1982) Development of physicochemical speciation procedures to investigate the toxicity of copper, lead, cadmium and zinc towards aquatic biota. Anal. Chim. Acta, 141, 73-94. 

If copper interactions were minimized in real seawater, abundant metals of lesser sulfide affinity would take up some of the slack. ITiis is partially evident from analyses of the type in Table III. For example, nickel has mixed layer concentrations on the order of nanomolar (22), and its sulfide equilibria and inorganic seawater speciations may resemble those of zinc (lv-19.31.32). Titration, however, should only lower free sulfide to a Table m SH equivalence point, or, to roughly picomolar. In a follow up to 1Z, Dyrssen and coworkers treat Cu(II) as a variable parameter, and find that in its absence, nickel, zinc and lead can all become sulfides while the bisulfide ion still hovers well above pM (18). Again, it must be emphasized that error margins in the various equilibria remain to be investigated. 

In soil research, the term speciation is often applied to operationally defined fractionation of heavy metals into five or more components.25 Typically, water soluble, exchangeable, organically bound (which includes what is in biomass), amorphous oxide bound, crystalline oxide bound, and residual fractions are measured.26 Sometimes residual fractions are further subdivided according to particle size distributions to give amounts in sand, silt, and clay fractions. Similar fractionation procedures are often applied to aquatic sediments.27 In arid regions, often the calcium carbonate bound fractions of heavy metals are also measured.28 Because of the constraints of detection limits, generally only cadmium, copper, iron, manganese, and zinc are usually monitored by flame spectrometry in such heavy metal speciation studies.28... 

Work on the speciation of iron and zinc in vegetable products is just beginning (23), and some progress is being made on the speciation of chromium (24) but not enough data have been accumulated to be of interest to the nutritionist. Speciation analysis has produced impressive advances in the toxicology of heavy metals. Similar advances can be expected in trace element nutrition if the diflBculties of methodology can be overcome. 

The most definitive assessment of the metal composition of metalloproteins comes from the application of element-specific detection methods. CE-ICP-MS provides information not only about the type and quantity of individual metals bound to the proteins but also about the isotopes of each element as well [11,12]. Elemental speciation has become increasingly important to the areas of toxicology and environmental chemistry. Such analytical capability also opens up important possibilities for trace element metabolism studies. Figure 1 depicts the separation of rabbit liver metallothionein containing zinc, copper, and cadmium (the predominant metal) using CE-ICP-MS with a high-sensitivity, direct injection nebulizer (DIN) interface. UV detection (200 nm) was used to monitor the efficiency of the CE separation of the protein isoforms (MT-1 and MT-2), whereas ICP-MS detection made it possible to detect and quantify specific zinc, copper (not shown), and cadmium isotopes associated with the individual isoform peaks. 

Interactions of trace elements with algae in the marine environment are being extensively studied (1-3, 5-12). Copper and zinc, both essential micronutrients required by phytoplankton, may be toxic at elevated concentrations (11-13). The biological effects of copper and zinc are strongly dependent on their speciation the activity of the free metal ion has been shown to be a key parameter (13). Toxic effects of Cu on marine algae have been observed in the range of pCu 10-12 (11-13). 

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