title: A simple and rapid method for isotopic analysis of nickel, copper, and zinc in seawater using chelating extraction and anion exchange.
abstract: Stable isotope ratios of nickel, copper, and zinc are powerful tools for elucidating the biogeochemical cycling of trace metals in the ocean. However, analytical difficulties have impeded isotopic studies of these metals. We present a simple and rapid method for simultaneous analysis of Ni, Cu, and Zn isotope ratios in seawater using NOBIAS Chelate-PA1 resin and anion exchange resin. A NOBIAS Chelate-PA1 resin column was used to quantitatively collect Ni, Cu, and Zn from seawater and thoroughly remove the seawater matrix. Subsequent anion exchange purified and separated the Ni, Cu, and Zn from each other. The blanks used in this method (0.22 ng for Ni, 0.29 ng for Cu, and 0.53 ng for Zn) were sufficiently low to determine the isotope ratios of Ni, Cu, and Zn in surface seawater. Using this method, we analyzed GEOTRACES reference seawater samples (i.e., SAFe D1 and SAFe D2), National Research Council Canada certified materials (i.e., CASS-5 and NASS-6), and seawater samples collected from different depths in the subarctic South Pacific. The results were consistent with previously reported values. This method is expected to accelerate isotopic research and contribute to our understanding of biogeochemical cycling in the ocean.
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan. Electronic address: shotaro@inter3.kuicr.kyoto-u.ac.jp.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Takano
authors.affiliation: School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Tanimizu
authors.affiliation: Division of Earth and Planetary Sciences, Kyoto University, Kitashirakawa Oiwake-cho, Kyoto 606-8502, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Hirata
authors.affiliation: Center for Research Promotion, The Research Institute for Humanity and Nature, Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8047, Japan.
authors.forename: Ki-Cheol
authors.initials: KC
authors.lastname: Shin
authors.affiliation: Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061 Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Fukami
authors.affiliation: Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061 Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sohrin
keywords: Anion exchange; Isotope ratio; NOBIAS; Ocean; Reference material; Trace metals