Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia.
Anal Chim Acta. 2013 May 2;775:106-13. doi: 10.1016/j.aca.2013.03.020. Epub 2013 Mar 16.
Stable copper (Cu) isotope geochemistry provides a new perspective for investigating and understanding Cu speciation and biogeochemical Cu cycling in seawater. In this work, sample preparation for isotopic analysis employed solvent-extraction with amino pyrollidine dithiocarbamate/diethyl dithiocarbamate (APDC/DDC), coupled with a nitric acid back-extraction, to concentrate Cu from seawater. This was followed by Cu-purification using anion-exchange. This straightforward technique is high yielding and fractionation free for Cu and allows precise measurement of the seawater Cu isotopic composition using multi-collector inductively coupled plasma mass-spectrometry. A deep-sea profile measured in the oligotrophic north Tasman Sea shows fractionation in the Cu isotopic signature in the photic zone but is relatively homogenised at depth. A minima in the Cu isotopic profile correlates with the chlorophyll a maximum at the site. These results indicate that a range of processes are likely to fractionate stable Cu isotopes in seawater.
稳定的铜（Cu）同位素地球化学为研究和了解海水中的 Cu 形态和生物地球化学 Cu 循环提供了新的视角。在这项工作中，采用氨基吡咯烷二硫代氨基甲酸盐/二乙基二硫代氨基甲酸盐（APDC/DDC）溶剂萃取，结合硝酸反萃取，从海水中浓缩 Cu 来进行同位素分析的样品制备。然后使用阴离子交换进行 Cu 纯化。该技术简单，Cu 的产率高，无分馏，可使用多接收电感耦合等离子体质谱仪精确测量海水 Cu 同位素组成。在贫营养的塔斯曼海北部测量的深海剖面显示在光区的 Cu 同位素特征存在分馏，但在深处相对均匀。Cu 同位素剖面的最小值与该位点的叶绿素 a 最大值相关。这些结果表明，一系列过程可能会使海水中的稳定 Cu 同位素分馏。
