Nickel isotope analysis

The Nickel Producers Environmental Research Association (NiPERA) is sponsoring research on the application of inductively coupled plasma-mass spectroscopy (ICP-MS) to isotopic analysis of nickel in biological samples, on the development of sampling instrumentation for assessing workers exposure to nickel in the nickel industry, and on methods for utilizing newly developed analytical methods, such as laser beam ionization mass spectrometry, for the identification and speciation of nickel compounds in powders and dusts with particular reference to nickel refining. 

Edwards, T. W. D., W. M. Buhay, R. J. Elgood H. B. Jiang, 1994. An improved nickel-tube pyrolysis method for oxygen isotope analysis of organic matter and water. Chem. Geol. (Iso. Geosci. Sect.) 114 179-183. 

Fe Q-band ENDOR study of the isotopically enriched Ni-C state of D. gigas and D. desulfuricans hydrogenases and Ni-B state of D. desulfuricans revealed a weak coupling between the Fe and the nickel atoms when the enzyme was in the Ni-A forms while no coupling was observed for the Ni-B form (186). A careful analysis of linewidth of Ni-A and Ni-B EPR signals detected in Fe enriched and nonenriched hydrogenase samples indicated that hyperfine interactions are lost in the spectral linewidth and, hence, nonde-tectable. 

Among the commonly observed spectral overlap problems due to molecular oxide and molecular hydroxide ions are those due to TiO+ (with 5 isotopes of Ti from mass 46 to 50) that result in overlaps with a minor isotope of nickel, 62Ni+ both isotopes of copper, 63Cu+ and 65Cu + and the two major isotopes of zinc, MZn+ and 66Zn+. Calcium oxide and hydroxide ions overlap with all five isotopes of nickel, both isotopes of zinc, and three of the four isotopes of iron. The analysis of rare earth elements is particularly complicated by molecular oxide and hydroxide ion spectral overlaps [141,142]. 

Yoshinaga and Morita used isotope dilution in conjunction with ICP-MS to measure mercury in biological and environmental samples [45]. The same group used microwave-induced plasma mass spectrometry for the isotope dilution analysis of selenium in biological materials [46]. Analysis of nickel via isotope dilution and ICP-MS has been reported by Patriarca et al [47]. 

The online mass spectrometric analysis of the evolving gas under open-circuit conditions and at different electrode potentials was carried out using nickel film sputter deposited onto a thin Teflon film as a working electrode, which was interfaced to the inlet of the mass spectrometer. Deuterium labeling allowed the rate of partial reactions (19.11) and (19.12) and the isotopic composition of the evolving gas to be monitored as a function of the electrode potential in parallel to faradaic current measurements, providing a solid evidence of the electrochemical mechanism of (electro) catalytic hypophosphite oxidation. 

Analytical Methods and Speclatlon Electrothermal atomic absorption spectrophotometry (ETAAS), differential pulse adsorption voltammetry (DPAV), isotope-dilution mass spectrometry (ID-MS), and inductively coupled plasma mass spectrometry (ICP-MS) furnish the requisite sensitivity for measurements of nickel concentrations in biological, technical and environmental samples (Aggarwal et al. 1989, Case et al. 2001, Stoeppler and Ostapczuk 1992, Templeton 1994, Todorovska et al. 2002, Vaughan and Templeton 1990, Welz and Sperling 1999). The detection limits for nickel determinations by ETAAS analysis with Zeeman background correction are approximately 0.45 jg for urine,... 

A few reports are available where TIMS has been used for cosmochemical analysis. The recent report of Yamakawa et al. (2009) deals with sequential chemical separation technique for Cr, Fe, Ni, Zn, and Cu in terrestrial and extraterrestrial silicate rocks for precise and accurate determination of elemental concentration. The chemical technique uses a combination of cation-anion exchange chromatography and Eichrom nickel specific resin. The developed method was tested to a variety of matrixes bulk meteorite (Allende), terrestrial peridotite (JP-1), and basalt (JB-lb). Concentrations of each element were determined by TIMS. The analytical procedure was further extended to obtain high-precision isotope data for Cr. The method is capable to determine the isotopic ratios of Cr/ Cr and Cr/ Cr with precision of 5 X 10 and 1 x 10, respectively. The method can be equally applicable in cosmochemical studies, like Mn-Cr chronology and investigation of nucleosynthetic isotopic anomalies in meteorites. The elemental concentrations measured by TIMS in Allende are, for example, Cr 3,600 0.007 ppm, Fe 233,400 0.009 ppm, Ni 14,020 0.006 ppm, Cu 107 0.013 ppm, and Zn 117.8 0.01 ppm. The detection of Al (0.7 Ma) in the Allende meteorite proves that nucleosynthesis is still active in the Milky Way as the half-life of A1 is much less than the timescale of galactic evolution (10 years). 

After microwave-assisted digestion of the sample with a mixture of nitric acid and hydrogen peroxide, during which equilibration with the isotopically enriched spikes added also took place, formic acid was used to convert the isotope-diluted elements into volatile compounds in a photo-reactor. In the case of iron and nickel, the corresponding volatile carbonyl compounds are most likely formed, whereas in the case of selenium, hydride compounds are obtained. A schematic representation of the UV-PVG-ICP-IDMS setup is shown in Figure 8.10. The good accuracy of results was demonstrated by the successful analysis of certified reference materials. Extremely low LODs of 0.18, 1.0, and 1.7 pgg were found for Ni, Fe, and Se, respectively, which are improvements of a factor of 30 for the two metals and 150 for Se compared with conventional pneumatic solution nebulization. 

The most important degradative method for the determination of urea in the natural water samples is based on its conversion to carbon dioxide and ammonia by hydrolysis obtained with a nickel metalloenzyme (urease). In the manual procedure outlined by McCarthy [89] for the analysis in seawater, the enzymatic hydrolysis of urea was carried out at 50°C for 20 min, in the range of pH from 6.4 to 8.0, using a solution of crude lyophilized jack beam urease. After the samples were cooled at room temperature, NH4 concentration was determined by manual colorimetric method after cooling the samples at room temperature. The ambient concentration of NH4 and the analytical blank (NH4 contained in the reagents and in the urease solution) have to be subtracted for any sample to obtain the concentration of urea. In this reference study, the precision (RSD) was 1% at the concentration of urea equal to 1 pmol N A manual indirect methodology was also described by Katz and Rechnitz [209] and the method was revised in other following studies [9,53,197,198]. It persists with minor modifications in recent works on the field and in culture experiments [71,199-202] and for determination of isotope ratio in urea by elemental... 

Figure 5.8 Chalcopyrite grains imbedded in a prepolished conductive epoxy substrate as imaged by (a) SEM, (b) EDX (the Ni distribution shown), and (c) SIMS operated in the microscope mode (the CsNF secondary ions are displayed). The SIMS image resolution is defined via line scan analysis (see white line in SIMS image) as illustrated in (d) and in (e). Raw MCs signals, where M is an isotope of Nickel, are shown.

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