Yoshimura Toshihiro, Araoka Daisuke, Tamenori Yusuke, Kuroda Junichiro, Kawahata Hodaka, Ohkouchi Naohiko
Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15, Natsushima, Yokosuka 237-0061, Japan; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567, Japan.
J Chromatogr A. 2018 Jan 5;1531:157-162. doi: 10.1016/j.chroma.2017.11.052. Epub 2017 Nov 24.
We describe the mass descrimination and validation of an offline method for purification of Li, Mg and S with an ion chromatograph coupled to an automated fraction collector for use prior to stable isotope measurements. Significant sub-fraction mass fractionation was observed for both the Li and the Mg stable isotope ratios. The lighter Li and heavier Mg isotopes were preferentially retained by the column, resulting in Li/Li and Mg/Mg biases up to 85.8‰ and 0.95‰, respectively. The isotopic compositions of Li, Mg, and S separated from seawater were δLi = +30.9‰, δMg = -0.83 ± 0.10‰, and δS = +19.4 ± 0.6‰; each chromatographic peak was completely recovered, and the results were in good agreement with the published values regardless of whether or not chemical suppressor was used. The purification method enables multi-isotope analysis of a sample using various mass spectrometry techniques, such as multiple-collector inductively coupled plasma and thermal ionization mass spectrometry.
我们描述了一种离线方法的质量辨别和验证，该方法利用与自动馏分收集器联用的离子色谱仪对锂、镁和硫进行纯化，以便在稳定同位素测量之前使用。对于锂和镁的稳定同位素比率，均观察到显著的亚馏分质量分馏。较轻的锂同位素和较重的镁同位素优先被色谱柱保留，导致Li/Li和Mg/Mg偏差分别高达85.8‰和0.95‰。从海水中分离出的锂、镁和硫的同位素组成分别为δLi = +30.9‰、δMg = -0.83±0.10‰和δS = +19.4±0.6‰；每个色谱峰均被完全回收，无论是否使用化学抑制器，结果均与已发表的值高度吻合。该纯化方法能够使用多种质谱技术对样品进行多同位素分析，如多接收电感耦合等离子体质谱和热电离质谱。
