2019 Volume 35 Issue 9 Pages 1015-1020
Zirconium, niobium, hafnium, and tantalum are dissolved in seawater as hydroxide complexes at a concentration as low as 0.01 – 370 pmol kg−1 and are expected to be potential tracers for water masses in the ocean. Herein, we report a new analytical method for the multielemental determination of the four elements on the basis of column extraction, using a NOBIAS Chelate-PA 1 resin that contains ethylenediaminetriacetic acid groups. The elements were collected on the resin from seawater that had been added with 3.8 mM HF at pH 6.0, and were eluted with 5 M HF. After the evaporation of 5 M HF, the elements were dissolved in 0.5 M HNO3–6 mM H2SO4–1 mM HF and were determined by a high resolution ICP-MS, using a calibration curve method. We optimized the procedure to achieve quantitative recoveries and low backgrounds for the elements, although the complex formation between the metal ions and NOBIAS Chelate-PA 1 was decelerated by the seawater matrix. The method was tested by investigating the seawater samples of reference material and those collected from the depths at a station in the western North Pacific Ocean.
