Zinc isotopes

Marechal CN, Telouk P, Alberede F (1999) Precise analysis of copper and zinc isotopic compositiorrs by plasma-source mass spectrometry. Chem Geol 156 251-273 Martin P, Hancock GJ, Paulka S, Akber RA (1995) Determination of Ac-227 by alpha-particle spectrometry. Appl Radiat Isot 46 1065-1070... 

The concept of selectivity and specificity has been applied to characterize interferences appearing in two different ICP-MS techniques (Horn [2000]). Classical ICP-MS with pneumatic nebulization and ETV-ICP-MS are compared for the determination of traces of zinc in sea-water. Whereas spectral interferences decrease using the ETV device, nonspectral interferences increase significantly (Bjorn et al. [1998]). A quantitative comparison of the both analytical procedures, here called PN (pneumatic nebulization) and ETV (electrothermal vaporization, Sturgeon and Lam [1999]) is possible by means the specificity as a function of the Zn concentration (Horn [2000]). The spectral interferences on the four zinc isotopes are listed in Table 7.4. 

Table 7.4. Seawater components and their spectral interferences with zinc isotopes...

The specificity vectors of the four zinc isotopes are given in matrix form as follows ... 

Budd, P. D., Lythgoe, P., McGill, R. A. R., Pollard, A. M., and Scaife, B. (1999). Zinc isotope fractionation in liquid brass (Cu-Zn) alloy potential environmental and archaeological applications. In Geoarchaeology exploration, environments, resources, ed. Pollard, A. M., London, Geological Society Special Publication, pp. 147-153. 

Leya I, Wider R, Halliday AN (2000) Cosmic-ray production of tungsten isotopes in lunar samples and meteorites and its implications for Hf-W cosmochemistry. Earth Planet Sci Lett 175 1-12 Loss RD, Lugmair GW (1990) Zinc isotope anomalies in Allende meteorite inclusions. Astrophys J 360 L59-L62... 

Virag A, Zinner E, Lewis RS, Tang M (1989) Isotopic compositions of H, C, and N in C8 diamonds from the Allende and Murray carbonaceous chondrites. Lunar Planet Sci XX 1158-1159 Volkening J, Papanastassiou DA (1989) Iron isotope anomalies. Astrophys J 347 L43-L46 Volkening J, Papanastassiou DA (1990) Zinc isotope anomalies. Astrophys J 358 L29-L32 Wadhwa M, Zinner EK, Crozaz G (1997) Manganese-chromium systematics in sulfides of unequilibrated enstatite chondrites. Meteorit Planet Sci 32 281-292... 

Mar hal CN, Douchet C, Nicolas E, Albarede F (2000) The abundance of zinc isotopes as a marine biogeochemical tracer. Geochem Geophys Geosyst 1 1999GC-000029 Marechal C, Albarede F (2002) Ion-exchange fractionation of copper and zinc isotopes. Geochim Cosmochim Acta 66 1499-1509... 

The data described above demonstrate a substantial fractionation of isotopes for both Cu and Zn. Zinc isotopic variability is particularly noticeable in the marine environment the 8 Zn... 

Pichat S, Douchet C, Albarede F (2003) Zinc isotope variations in deep-sea carbonates from the eastern equatorial Pacific over the last 175 ka. Earth Planet Sci Lett 210 167-178 Price NM, Morel EMM (1990) Cadmium and cobalt substitution for zinc in a zinc-deficient marine diatom. Nature 344 658-660... 

From an NMR perspective, Zn (the only NMR-active zinc isotope) is among a number of potentially important but insensitive metal nuclei such as Ca and Mg. However, Zn NMR spectra of aqueous Zn+ are different from Ca and Mg NMR spectra of aqueous Ca + and Mg + in some respects. For example, Zn NMR spectra of aqueous Zn + have marked concentration dependences in terms of the half-band widths (Avi/2) compared with those of Ca and Mg NMR spectra of aqueous Ca and Mg . 

The concentration of Cl- increases somewhat in addition, the zinc isotopes are now also detected, as shown in Fig. 6. It is not clear whether the appearance of zinc at the surface is the result of diffusion or of a decrease in film thickness. 

Figure 6. Narrow range of the high-resolution positive T0FS1MS spectrum of Fig. 5 showing zinc isotopes separated from organic ions.

Mar chal, C.N., Albarede, F., and Emmanuel, N. (1997) Natural variations in copper and zinc isotopic compositions. In Seventh Annual V.M. Goldschmidt Conference, 131-132, LPI Contribution No. 921, Lunar and Planetary Institute Houston. 

Locally an increase of the cross section by a factor of 5.8 was measured for element 110 in cold fusion reactions when the beam was changed from 62Ni to f>4Ni. It was speculated that this increase could be due to the increased value of the projectile isospin. However, the assumption could not be confirmed in the case of element 112 which was synthesized using the most neutron rich stable zinc isotope with mass number 70. 

From the isotopic decomposition of normal zinc one finds that the mass-64 isotope, 4Zn, is the mostabundant of zinc isotopes 48.6% ofall Zn. Using the total abundance of elemental Zn = 1260 per million silicon atoms, making Zn the 23rd most abundant element in solar-system matter, this isotope has... 

The bombardment of natural zinc (isotopes 64. 66. 67, 68, and 70) with slow neutrons yields 3 different radioactive isotopes of zinc, which we may designate as A, B, and C. These are identified by the method of cross bombardment as follows ... 

Bombardment of natural copper (isotopes 63 and 65 with protons yields isotope A, together with a fourth zinc isotope, D, a K eapturer. Bombardment of natural gallium, (isotopes 69 and 71) with energetic deutcrons yields B, but not A, C, or D. 

Assuming that A, B, C, and D have mass numbers different from those of the inactive zinc isotopes, assign mass numbers to each. 

There are several disadvantages of using stable Isotopes as labels. They are more expensive than radioisotopes and the supply is limited. Analysis requires extensive, time-consuming sample preparation, and requires use of costly Instruments not readily available to all investigators. The cost and supply of stable Isotopes limits the quantities which can be used. One mg of 99.7% Zn costs 0.45. The same purity of Zn cost 155 per mg. The cost is expected to Increase in the near future, when a new batch of zinc Isotopes becomes available. Thus zinc Isotopes for use in a single human study may cost thousands of dollars. Specific Isotopes are sometimes out of stock and not available for several months or longer. 

The meals were extrinsically labelled by added 65 Zn. The rationale for this method is that a complete isotope exchange takes place between the added radioactive zinc isotope and the zinc present in the meal. Measurements of the uptake of radioactive iron isotopes in blood or in the whole body have been used for many years in studies of iron absorption. (12, 13, 14). The absorption in the present study is determined from measurement of the whole body retention of the radioisotope. However, this can not be done until the non-absorbed fraction of the isotope has left the body. During this periode of time some of the initially absorbed has been extrected. A correction of retention data... 

Mass spectrometry of zinc Isotopes has been realized using either chelates on a solids probe(10,11,17) or thermal Ionization of purified solutions(12). Both of these approaches require a chemical separation of all of the metals and this separation must be accomplished In an environment free of contamination from the metal(s) of Interest In the part-per blllion range (19). Neutron activation also requires a set of separation steps. In this case the requirement for a contamination-free environment Is the same but the chemical separation Is mainly to remove sodium and chlorine (2). 

For metabolic studies, zinc isotopes can be used and both stable and radioactive forms are available. Isotopic methods can give valuable insights into the dynamics of zinc absorption, tissue uptake and excretion. 

Zinc metabolic studies in which the difference between the total dietary intake and the total excretion in faeces and in urine, is measured over a period of several days. The difficulties of this procedure include problems of ensuring complete collections of excreta and measurement of losses in sweat, shed skin and hair. These losses although minor, may cause cumulative errors. Analytical problems caused by accidental zinc contamination are also a worry, although here the use of stable zinc isotopes and mass spectrometry or neutron activation is an advantage. 

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