固相萃取-电感耦合等离子体质谱法测定地表高盐水体中的痕量稀土元素  

Determination of Rare Earth Elements in High-Salt Water by ICP-MS After Pre-Concentration Using a Chelating Resin

作　　者：朱兆洲[1] 杨鑫鑫 李军[1] 何会军[2] 张紫静 闫文蕊 ZHU Zhao-zhou;YANG Xin-xin;LI Jun;HE Hui-jun;ZHANG Zi-jing;YAN Wen-rui(Tianjin Key Laboratory of Water Resource and Water Environment,Tianjin Normal University,Tianjin 300387,China;Key Laboratory of Marine Chemistry Theory and Technology,Ministry of Education,Ocean University of China,Qingdao 266100,China)

机构地区：[1]天津师范大学天津市水资源与水环境重点实验室,天津300387 [2]中国海洋大学海洋化学理论与工程技术教育部重点实验室,山东青岛266100

出　　处：《光谱学与光谱分析》2022年第6期1862-1866,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41673026)资助。

摘　　要：基于电感耦合等离子体质谱(ICP-MS)建立测定地表高盐水体中痕量稀土元素的分析方法,提出UV/H_(2)O_(2)去除地表水体中有机物的新策略。地表水体中的溶解态稀土浓度极低,质量浓度在ng·L^(-1)数量级,分析测试非常困难。当水体中总溶解性固体超过1 g·L^(-1)时,样品直接测试会造成严重的质谱干扰,同时可能会导致雾化器、截取锥和样品锥阻塞。因此,测试高盐水体中的稀土元素需要先去除水体中的盐类。为提高测试的准确度,样品测试前通常需要对水体进行预富集以增加待测物质量浓度。但是,内陆地表水体中有机物浓度较高,在进行预富集的过程中有机物和稀土元素发生络合作用,使得溶解态稀土在富集时发生分异,对预富集工作也是一项挑战。首先在样品中加入H_(2)O_(2),将样品放入紫外消解系统中氧化去除水体中的有机物,消解后水体中有机碳的浓度可降低至0.5 mg·L^(-1)。然后采用NobiasPA1固相树脂对样品进行预富集,步骤如下:首先使用流速为2.2 mL·min^(-1)的硝酸,超纯水和醋酸铵缓冲液依次分别清洗预富集系统,去除预富集系统中可能残留的稀土元素;然后用流速为2.0 mL·min^(-1)的醋酸铵缓冲液、样品和醋酸铵缓冲液依次分别通过固相萃取柱,富集样品中的稀土元素并去除吸附在树脂柱上的盐类;最后使用流速为0.7 mL·min^(-1)的HNO_(3)溶液淋洗树脂柱并收集样品。ICP-MS测试样品时,选择^(115)In为内标校正基体效应。研究结果表明在pH 4.6±0.1的情况下,各稀土元素的检出限和空白值分别在0.34~22.0和0.34~12.9 ng·L^(-1)之间;稀土元素检出的相对标准偏差(n=5)<5%;稀土标准溶液的加标回收率在97%~101%之间。将该方法用于渤海海水、海河河口水体和西藏雅根错水体,加入Tm作为内标,样品的加标回收率在98%~101%,相对标准偏差(n=3)<5%。这说明该方法适用于地表高盐水体中溶解态稀Based on inductively coupled plasma mass spectrometry(ICP-MS),a novel method for the accurate determination of ultra-trace rare earth elements(REEs)in high-salt surface water was established.The interfering with organic matter in the surface water was eliminated by UV/H_(2)O_(2).The concentration of REEs in surface water is at the ng·L^(-1)level,making the quantitative determination of dissolved REEs very difficult.The matrix effect of ICP-MS is serious when the total dissolved solid concentration is higher than 1 g·L^(-1).Moreover,nebulizer,sampler cone,and skimmer Cone may be blocked in the process of measuring.Therefore,it is necessary to remove salt from the water when the concentration of REEs in high-salt water is determined.REEs in water is needed to preconcentrate before measurement.However,the concentrations of organic matter are usually high in the surface water.The complexation of organic matter can lead to a fraction of REEs during-pre-concentration.The preconcentration of dissolved REEs is also a challenge.In this work,H_(2)O_(2)was added to the sample before the preconcentration.The sample was subsequently irradiated with a digester,which destroyed the organic ligands of REEs.The dissolved organic carbon(DOC)concentration in water could be reduced to approximately 0.5 mg·L^(-1).The REEs in water were pre-concentrated through a Nobias PA1 chelating resin column.Proceed as follows:initially,the preconcentrated system was respectively rinsed with HNO_(3),pure water,and NH_(4)AC solution in sequence at a flow rate of 2.2 mL·min^(-1)to remove the possible residual REEs.Then,the column was respectively rinsed with NH_(4)AC solution,sampler,and NH_(4)AC solution in sequence at a flow rate of 2.0 mL·min^(-1)to preconcentrate REEs and remove the loaded salts.Finally,the REEs were eluted with HNO_(3) at a flow rate of 0.7 mL·min^(-1)and analyzed by ICP-MS.A ^(115)In internal standard was used to correct instrument fluctuation and matrix effect.Results showed that the procedural blanks,detection limits,a

关 键 词：螯合树脂 电感耦合等离子体质谱 有机物 高盐水体 稀土元素 

分 类 号：O657.63[理学—分析化学]