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    石墨炉原子吸收光谱法测定镍基高温合金中铅、铋、硒元素的含量

    Determination of Lead, Bismuth, and Selenium Elements in Nickel Based High Temperature Alloys by Graphite Furnace Atomic Absorption Spectrometry

    • 摘要: 取0.100 0 g镍基高温合金样品置于100 mL聚四氟乙烯烧杯中,加入2.0 mL盐酸、1.0 mL硝酸、0.5 mL氢氟酸,盖上塑料表面皿,于90 ℃水浴加热约60 min至样品完全溶解,冷却后,溶液转移到100 mL塑料容量瓶中,加入10 mL硝酸,用水稀释并定容,混匀。采用石墨炉原子吸收光谱法测定其中铅、铋、硒元素,通过自动进样器,依次加入3 μL 250 g·L-1磷酸二氢铵溶液、5 μL 250 g·L-1硫脲溶液、8 μL 1 000 μg·L-1 Pd(NO32-500 μg·L-1 Mg(NO32溶液作为测定铅、铋、硒元素的基体改进剂,通过交流纵向塞曼背景校正干扰,以基质匹配的混合标准溶液绘制工作曲线。结果表明,铅、铋、硒元素的质量浓度在一定范围内与对应的吸光度呈线性关系,检出限(3s/k)为0.01~0.03 μg·L-1。方法用于分析镍基高温合金标准物质,测定值基本在认定值的不确定度范围内,且测定值的相对标准偏差(n=6)均不大于25%。方法用于分析3个实际镍基高温合金样品,与辉光放电质谱法比较,所得测定值基本一致。

       

      Abstract: 0.100 0 g of nickel based high temperature alloy sample was taken and placed in a 100 mL-polytetrafluoroethylene beaker. 2.0 mL of hydrochloric acid, 1.0 mL of nitric acid, and 0.5 mL of hydrofluoric acid were added. The beaker was covered with a plastic surface dish and the mixture was heated at 90 ℃ water bath for about 60 min until the sample was completely dissolved. The solution was cooled and transferred to a 100 mL-plastic volumetric flask. 10 mL of nitric acid was added, and the solution was made its volume up to 100 mL with water and mixed well. Lead, bismuth, and selenium elements in the solution were determined by graphite furnace atomic absorption spectrometry, and 3 μL of 250 g·L-1 ammonium dihydrogen phosphate solution, 5 μL of 250 g·L-1 thiourea solution, and 8 μL of 1 000 μg·L-1 Pd(NO3)2 and 500 μg·L-1 Mg(NO3)2 solution were sequentially added as matrix modifiers for the determination of lead, bismuth, and selenium elements by the automatic sampler. The determined results were corrected by alternating longitudinal Zeeman background and standard curves were drawn with the matrix matching mixed standard solutions. As shown by the results, linear relationships between values of the corresponding absorbance and mass concentration of lead, bismuth, and selenium elements were kept in definite ranges, with detection limits (3s/k) in the range of 0.01-0.03 μg·L-1. This method was used to analyze the nickel based high temperature alloy reference materials, and most of the determined values were within the uncertainty range of the certified values, with RSDs (n=6) of the determined values not more than 25%. This method was used to analyze 3 actual nickel based high temperature alloy samples, and the determined values were basically consistent with those obtained by glow discharge mass spectrometry.

       

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