引用本文:	蔺栩,崔广颢,曹阿翔,何倩,王继纲,张劲,刘茜.InertSep ME-2螯合树脂固相萃取-电感耦合等离子体质谱法测定海水中稀土元素[J].海洋科学,2025,49(2):112-124.

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InertSep ME-2螯合树脂固相萃取-电感耦合等离子体质谱法测定海水中稀土元素
蔺栩^1,2, 崔广颢^1,2, 曹阿翔^1,3, 何倩¹, 王继纲⁴, 张劲^1,5, 刘茜¹
1.中国海洋大学深海圈层与地球系统前沿科学中心, 海洋化学理论与工程技术教育部重点实验室, 山东青岛 266100;2.中国海洋大学化学化工学院, 山东青岛 266100;3.中国海洋大学环境科学与工程学院, 山东青岛 266100;4.中国海洋大学海洋高等研究院, 山东青岛 266100;5.日本富山大学理学部, 日本富山 9308555

摘要:

稀土元素是示踪海洋中物质来源及演化过程的良好示踪剂,但在海水中浓度极低(在pmol/kg级别),且高盐度的海水基质导致其有较高的测量难度。本研究建立了一种新型螯合树脂(InertSep ME-2)富集-电感耦合等离子体质谱联用测量海水中稀土元素的方法,并对螯合树脂的材料进行结构表征,探究树脂富集稀土元素的机制。X射线光电子能谱分析显示InertSep ME-2树脂主要由C、O元素构成,傅里叶红外光谱分析显示树脂吸附镥(Lu)后在657 cm^–1出现由羧酸根扭曲振动产生的特征峰,表明REEs以羧酸盐形态吸附于树脂中。条件实验结果表明,调节海水样品pH为5.0~5.1,使用12 mL 0.4 mol/L的NH₄Ac去除盐质,使用2 mL 2 mol/L的HNO₃作为洗脱液,样品的进样速度为3~6 mL/min,样品的富集效果最佳。本方法对海水中稀土元素富集的回收率在92%~103%,检出限范围为2.5×10⁻⁴~5.4×10⁻² pmol/kg,分析的精密度均小于5%(n=6),使用标准海水(NASS-7)验证方法的准确性较高,测定的浓度与文献平均值的差值在1倍标准偏差范围内。本研究建立的方法可以用于测定低盐度河水、河口盐度梯度区及高盐度海水样品中的稀土元素浓度。

关键词: 海水稀土元素 InertSep ME-2螯合树脂 ICP-MS 固相萃取

DOI：10.11759/hykx20241026001

分类号:O657.63

基金项目:国家自然科学基金(42306208);国家重点研发计划(2023YFF0805001)

Determination of rare earth elements in seawater by solid-phase extraction with InertSep ME-2 chelating resin followed by inductively coupled plasma mass spectrometry

LIN Xu^1,2, CUI Guanghao^1,2, CAO Axiang^1,3, HE Qian¹, WANG Jigang⁴, ZHANG Jing^1,5, LIU Qian¹

1.Frontier Science Center for Deep Ocean Multispheres and Earth System, the Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China;2.College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China;3.College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China;4.Institute for Advanced Ocean Study, Ocean University of China, Qingdao 266100, China;5.Faculty of Science, Academic Assembly, University of Toyama, 3190 Gofuku, Toyama 9308555, Japan

Abstract:

Rare earth elements (REEs) serve as excellent tracers for indicating the sources and evolutionary processes of substances in the ocean. Nevertheless, the concentration of REEs in seawater is exceedingly low, measured in picomoles per kilogram, and the presence of high salinity in the seawater matrix introduces substantial challenges for accurate measurement. This study developed a method for enriching trace REEs in seawater using a novel chelating resin (i.e., InertSep ME-2) coupled with inductively coupled plasma mass spectrometry for measurement. This study also conducted structural characterization of the chelating resin material and explored the mechanism of REE enrichment by the resin. X-ray photoelectron spectroscopy analysis showed that InertSep ME-2 resin is mainly composed of the elements C and O. Fourier transform infrared spectroscopy showed that the resin adsorbs Lu and exhibits a characteristic peak generated by the twisted vibration of carboxylate ions at 657 cm⁻¹, indicating that REEs are adsorbed in the form of carboxylate salts in the resin. The experimental results showed that the best enrichment effect was achieved when the pH of the seawater sample was adjusted to 5.0–5.1, with 12 mL of 0.4 mol/L NH₄Ac used to remove salts, 2 mL of 2 mol/L HNO₃ used as the eluent, and 3–6 mL/min set as the sample injection speed. The recovery rate of this method for REE enrichment in seawater ranged from 92% to 103%, with detection limits ranging from 0.000 25 pmol/kg to 0.054 pmol/kg. The precision of the analysis was less than 5% (n = 6). The accuracy of the method is verified to be high using the NASS-7 standard seawater, and the difference between the measured concentration and the literature average is within one standard deviation range. The method established in this study can be used to determine REE concentrations in low-salinity river water, estuarine salinity gradient zones, and high-salinity seawater samples.

Key words: seawater rare earth elements InertSep ME-2 chelating resin ICP-MS solid-phase extraction