直流辉光放电质谱分析导体和非导体样品的高纯铟片制样方法研究

利用高纯铟薄片作为粘合剂,选取适量的样品压在In薄片上,采用直流辉光放电质谱法(dc-GDMS)测定了以红磷、Al₂O₃、In₂O₃和Lu₂O₃为代表的块状非导体、粉末非导体和粉末导体这3类物质中杂质元素的含量。实验考察了取样量、放电参数对基体信号强度及其稳定性的影响,优化后的取样量和放电参数如下:对于块状非导体-红磷样品,选取约2mm×3mm×1mm大小,用手扳压力机压在In上,并将放电电流设在1.50mA,放电电压设在850V;对于粉末非导体-Al₂O₃样品,选择压在In上的Al₂O₃粉末直径约为3mm,放电电流为1.70mA,放电电压为900V;对于粉末导体-In₂O₃和Lu₂O₃样品,则选择压在In上的In₂O₃和Lu₂O₃粉末直径约为7~8mm,放电电流为1.80mA,放电电压为950V。将实验方法应用于红磷、Al₂O₃、In₂O₃和Lu₂O₃样品的测定,其中检测红磷的杂质元素检出限要比Al₂O₃的低1个数量级;对In₂O₃独立测定5次结果的相对标准偏差均在20%内,大部分元素的测定值与电感耦合等离子体质谱法(ICP-MS)基本一致,而Na、Al、Sn、Pb元素的测定值差别虽然有点大,但都在一个数量级上,对高纯金属产品的定级没有太大影响;Lu₂O₃中稀土元素的测定结果与ICP-MS的分析结果也基本一致。

Investigation on sample preparation method of high purity indium sheet in analysis of conductor and non-conductor sample by direct current glow discharge mass spectrometry

After the thin sheet of high-purity indium was used as adhesive, proper sample was selected and pressed on In thin sheet. Then the content of impurity elements was determined by direct current glow discharge mass spectrometry (dc-GDMS) in three types of materials including bulk non-conductor of red phosphorus, powder non-conductor of Al₂O₃ and powder conductor of In₂O₃ and Lu₂O₃. The effects of sample mass and discharge parameter on matrix signal intensity and its stability were investigated. The optimized testing conditions were listed as follows: (1) for the bulk non-conductor sample of red phosphorus, the proper sample size was about 2mm×3mm×1mm; the sample was pressed on In sheet by hand-operated press machine; the discharge current was 1.5mA and the discharge voltage was 850V; (2) for the powder non-conductor sample of Al₂O₃, the diameter of Al₂O₃ powder pressed on In sheet was about 3mm; the discharge current was 1.7mA and the discharge voltage was 900V; (3) for the powder conductor samples of In₂O₃ and Lu₂O₃, the diameter of In₂O₃ and Lu₂O₃ powder pressed on In sheet was about 7-8mm; the discharge current was 1.8mA and the discharge voltage was 950V. The experimental method was applied for the determination of red phosphorus, Al₂O₃, In₂O₃ and Lu₂O₃ samples. The detection limit of impurity elements in red phosphorus was one order of magnitude lower than those in Al₂O₃. The relative standard deviation of five independent measurements of In₂O₃ was within 20%, and the determination results of most elements were basically consistent with those obtained by inductively coupled plasma mass spectrometry (ICP-MS). Although the determination results of Na, Al, Sn and Pb had relatively large difference, the order of magnitude was the same, which had no great influence on the grading of high-purity metal products. The determination results of rare earth elements in Lu₂O₃ were also basically consistent with those obtained by ICP-MS.