Discipline: Ecology Environmental and Earth Sciences
Room: Exhibit Hall A
Tione Grant - University of the Virgin Islands
Co-Author(s): Brent A. Summers, University of South Florida, St. Petersburg; Matthias Sieber, University of South Florida, St. Petersburg; Tim M. Conway, University of South Florida, St. Petersburg;
Nickel (Ni) is an important micro-nutrient in oceanic environments, typically with low surface concentrations that increase with depth. Phytoplankton have been studied to incorporate Ni as a nutrient needed for the creation of urea and oxidative defenses. Ni isotope analyses offer the potential to provide insight into the cycling of Ni throughout the oceans. However, accurate and precise isotopic analysis requires the separation of Ni from the complex sea-salt matrix. At USF, we have previously used a two-stage method involving batch extraction by Nobias PA-1 chelating resin and AGMP-1 anion resin to separate Fe, Zn, and Cd from major salts in seawater, but we found that this method is not effective for separating Ni from Na. Therefore, in order to comprehensively investigate Ni isotope distributions, a different method for separating the trace metal from the large concentrations of major cations present in seawater was needed. Here, we present a new chemical purification method that separates the typical trace amounts of Ni from the high concentrations of major salts (Na and Mg) in seawater, allowing isotopic analysis. Our method builds upon our existing published methods using cation and anion exchange resins by incorporating a second cation resin microcolumn. We found this extra column allows us to fully separate Ni from Na, Mg and other interfering elements, before analysis of Ni by multi collector ICPMS. We also present new Ni isotope data from isotope standards and Atlantic seawater samples. References: Cameron, V., and D. Vance. Heavy Nickel Isotope Compositions in Rivers and the Oceans. Geochimica Et Cosmochimica Acta, vol. 128, 2014, pp. 195?211., doi:10.1016/j.gca.2013.12.007. Dupont, Christopher L., et al. ?Nickel Utilization in Phytoplankton Assemblages from Contrasting Oceanic Regimes. Deep Sea Research Part I: Oceanographic Research Papers, vol. 57, no. 4, 2010, pp. 553?566., doi:10.1016/j.dsr.2009.12.014. Conway, Tim M., et al. A New Method for Precise Determination of Iron, Zinc and Cadmium Stable Isotope Ratios in Seawater by Double-Spike Mass Spectrometry. Analytica Chimica Acta, vol. 793, 2013, pp. 44?52., doi:10.1016/j.aca.2013.07.025. Takano, Shotaro, et al. A Simple and Rapid Method for Isotopic Analysis of Nickel, Copper, and Zinc in Seawater Using Chelating Extraction and Anion Exchange. Analytica Chimica Acta, vol. 967, 2017, pp. 1?11., doi:10.1016/j.aca.2017.03.010. Yang, Shun-Chung, et al. A New Anion Exchange Purification Method for Cu Stable Isotopes in Blood Samples.? Analytical and Bioanalytical Chemistry, vol. 411, no. 3, 2018, pp. 765?776., doi:10.1007/s00216-018-1498-4.
Funder Acknowledgement(s): This project was funded by NSF grant Award OCE-1737136-1 to Dr. Tim Conway at the College of Marine Sciences, University of the South Florida.
Faculty Advisor: Dr. Tim Conway, firstname.lastname@example.org
Role: During this research project, I calculated the sample amounts that were used in testing the three experimental purification methods. I then conducted column chromatography on each of the purification methods using the samples created by my mentor; and collected each aliquot (30 ul) in separate 15 ml tubes. With each sample, I then added 380 uL of 2% HNO3 for analysis on the mass spectrometer. Finally, I applied blank and elemental standard corrections to the purification method data collected and created calibration curves corresponding to the data.