微波消解-电感耦合等离子体质谱法测定钽酸锂中痕量杂质元素

钽酸锂中杂质元素含量是划分产品等级的重要参数。样品中加入硝酸和氢氟酸后用微波消解法溶解样品,在线加入1.00 μg/mL的Cs内标溶液后,在H₂动态反应池模式下测定Ca、Fe、As、Se,在标准模式下测定其余元素,建立了微波消解-电感耦合等离子体质谱法(ICP-MS)测定钽酸锂中Be、B、Na、Mg、Al、K、Ca、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Se、Zr、Nb、Mo、Cd、Sb、Ba、Hf、W、Pb和Bi共28种杂质元素含量的方法。对溶样方法进行了优化,确定选用2 mL硝酸-2 mL氢氟酸体系于190 ℃保温120 min的方式微波消解样品。在优化的实验条件下,28种元素的检出限为0.003~0.37 μg/g,定量限为0.01~0.74 μg/g。采用实验方法测定市售钽酸锂样品中Mg、Al、Ca、Ti等28种杂质元素含量,测定结果的相对标准偏差(n=7)均小于5%,加标回收率为87%~112%。采用电感耦合等离子体原子发射光谱法(ICP-AES)对样品中Fe含量进行测定,测定结果与实验方法基本一致。

Determination of trace impurities in lithium tantalate by inductively coupled plasma mass spectrometry with microwave digestion

The content of impurity elements in lithium tantalate was an important parameter for grading products. The sample was dissolved by microwave digestion with nitric acid and hydrofluoric acid. 1.00 μg/mL Cs internal standard solution was added online. Ca, Fe, As and Se were determined at H₂ dynamic reaction cell mode, while other elements were determined at standard mode. Thus, a determination method of twenty-eight impurity elements (Be, B, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Zr, Nb, Mo, Cd, Sb, Ba, Hf, W, Pb and Bi) in lithium tantalate was established by inductively coupled plasma mass spectrometry (ICP-MS) with microwave digestion. The sample dissolution method was optimized. The following microwave digestion conditions were used: the sample was digested in microwave with 2 mL of nitric acid and 2 mL of hydrofluoric acid at 190 ℃ for 120 min. Under the selection experimental conditions, the limits of detection for 28 elements were between 0.003 μg/g and 0.37 μg/g, and the limits of quantification were in range of 0.01-0.74 μg/g. The proposed method was applied for the determination of twenty-eight impurity elements such as Mg, Al, Ca and Ti in commercial lithium tantalate samples. The relative standard deviations (RSD, n=7) of determination results were less than 5%, and the recoveries were between 87% and 112%. The content of Fe in sample was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the result was basically consistent with the experimental method.