火焰原子吸收光谱法测定镍基体料中铜

Determination of copper in nickel base materials by flame atomic absorption spectrometry

采用盐酸、硝酸溶解样品,加入氢氟酸和高氯酸,加热蒸发至干,以除去四氟化硅和过剩的氢氟酸,然后以稀盐酸溶解可溶性盐类,用火焰原子吸收光谱法测定溶液中的铜。考察了不同比例的混合酸溶解样品的效果,对测定介质种类、酸度和共存元素的干扰进行了试验。结果表明:盐酸+硝酸+氢氟酸+高氯酸可以将样品消解完全;2.5%(体积分数)以内的盐酸介质不影响铜的测定;在100mL溶液中,40mg镍、1mg钴、10mg铬对0.0 2mg铜的测定没有影响;200mg的铁对0.02mg以上的铜的测定也没有影响,但不同量的铁对0.01～0.02mg铜的测定有所影响,因此测定低含量铜时可采用在空白溶液中加入铁基体的方法消除干扰。铜的检出限为0.011μg/mL,测定下限为0.038μg/mL。方法用于镍基体料实际样品分析,测定结果的相对标准偏差(n=11)在1.7%～2.0%范围,加标回收率在98%～108%之间。

The sample was dissolved in hydrochloric acid and nitric acid.hydrofluoric acid and perchloric acid were added to sample solution.The sample solution was heated and evaporated until dry to remove silicon tetrafluoride and hydrofluoric acid.After soluble salt was dissolved in dilute hydrochloric acid,copper in the solution was determined by flame atomic absorption spectrometry.The effect of dissolving sample with different proportion of mixed acids and the interference of different medium,acidity and coexistent elements were examined.The result indicated the sample could be completely dissolved in hydrochloric acid ＋ nitric acid＋ hydrofluoric acid ＋ perchloric acid.Hydrochloric acid with the volume fraction of less than 2.5% did not affect the determination of copper.In 100 mL of solution,40 mg of nickel,1 mg of cobalt and 10 mg of chromium did not affect the determination of 0.02 mg of copper.200 mg of iron did not also affect the determination of more than 0.02 mg of copper.However,different amounts of iron affected the determination of 0.01-0.02 mg of copper.Therefore,interference for determining low content of copper may be eliminated by adding iron in blank solution.The detection limit of copper was 0.011 μg/mL and the limit of quantitation was 0.038 μg/mL.The method was used for real sample analysis of nickel substrate.The RSD of the determination result（n=11） was within the range of 1.7%-2.0% and the recovery was between 98%-108%.