微柱富集-火焰原子吸收光谱法测定高纯锂盐中痕量钙、镁  

FAAS Determination of Calcium and Magnesium in High-purity Lithium Salts with Pre-concentration on Micro-column

作　　者：伊文涛[1] 闫春燕[1] 马培华[2] 李法强[2] 王连亮[2] 

机构地区：[1]枣庄学院化学化工系,枣庄277160 [2]中国科学院青海盐湖研究所,西宁810008

出　　处：《理化检验（化学分册）》2009年第7期775-777,780,共4页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：国家"十五"科技攻关计划滚动支持项目(2004BA602B-01)

摘　　要：痕量钙（Ⅱ）及镁（Ⅱ）借以IRC747树脂填充的微柱从pH8的试液中富集分离，试液通过微柱的流速为2．0mL·min^-1。先后用0．5mol·L^-1乙酸及水作淋洗液，将微柱上吸附的大量锂离子除去后，用1．0mol·L^-1盐酸作淋洗液，以2．5mL·min^-1的速率流经微柱将Ca^2＋及Mg^2＋离子洗脱，收集此洗脱液作火焰原子吸收光谱法测定用。在原子吸收光度法测定中，采用柠檬酸溶液及镧盐溶液作为钙的释放剂，镧盐及锶盐的混合溶液作为镁的释放剂。此外，方法中还加入适量的十六烷基三甲基溴化铵溶液作为增敏剂，可使钙及镁的测定灵敏度依次提高达25％及22%的幅度。应用所提出的方法测定了高纯碳酸锂及氯化锂中痕量钙、镁，所得结果与电感耦合等离子体原子发射光谱法的测定值相符，测定结果的相对标准偏差（n=8）均小于3％。用标准加入法测得方法的回收率在99．1％～100．9％之间。Traces of Ca^2＋ and Mg^2＋ testing solution of pH 8 were separated and enriched by passing through the micro-column packed with IRC 747 resin, at the flow-rate of 2. 0 mL ·min^-1. After removing the Li^＋ from the column by elution with 0. 5 mol · L^-1 HOAc and H2O, Ca^2＋ and Mg^2＋ were desorbed from the column with 1.0 mol· L^-1 HCl as eluant at the flow-rate of 2. 5 mL · min^-1. The eluate was collected and used for FAAS determination. Solutions of citric acid and La（ Ⅲ ） salt were used as releasing agent for Ca^2＋ , and mixed solution of La（Ⅲ） and St（ Ⅲ ） salts was used as releasing agent for Mg^2＋. In addition, the sensitivity of determination of Ca^2＋ and Mg^2＋ was raised by the addition of CTMAB solution, and the magnitude of enhancement of sensitivity was attained to values of 25% for Ca^2＋ and 22% for Mg^2＋. In analyzing samples of high-purity lithium carbonate and lithium chloride by this method, results of Ca^2＋ and Mg^2＋ contents found were in consistency with the results obtained by ICP-AES, with values of RSD＇s （n=8） less than 3%, the recovery ranged from 99. 1% to 100. 9%.

关 键 词：火焰原子吸收光谱法 微柱预富集 钙 镁 高纯锂盐 

分 类 号：O657.3[理学—分析化学]