电感耦合等离子体原子发射光谱法测定钽中微量铌的多元光谱拟合干扰校正方法研究

Research on the multicomponent spectral-fitting interference correction for the determination of micro niobium in tantalum by inductively coupled plasma atomic emission spectrometry

钽样品经氢氟酸消解后,未经基体分离,直接以多元光谱拟合等离子体原子发射光谱法测定消解液中微量铌杂质元素。Nb 269.706 nm分析谱线仅受到Ta基体的部分重叠光谱干扰,扫描光谱图较为简单;Nb 292.781 nm、Nb 309.418 nm和313.079 nm分析谱线均受到OH带和Ta基体的光谱干扰,扫描光谱图均较为复杂,不利于分析。在选定的Nb 269.706nm分析谱线下,建立合理的多元光谱拟合(MSF)模型,有效校正了高含量钽基体对微量铌的光谱干扰。在此方法中铌的检出限为0.000 9 mg/L。方法用于钽样品中铌的测定,RSD为0.61%,加标回收率为101%;用于测定准确配置的合成样品时,在满足钽浓度小于且接近MSF模型预设的钽基体浓度和铌浓度大于0.500 mg/L时,相对误差都小于1.0%。

After the tantalum sample was digested with hydrofluoric acid,trace niobium in the solution was directly determined by inductively coupled plasma atomic emission spectrometry（ICP-AES） without separation of matrix.The analytical line of Nb 269.706 nm was only partially overlaped by spectral lines of Ta matrix,so the scanning spectrogram was relatively simple.The analytical lines of Nb 292.781 nm,Nb 309.418 nm and 313.079 nm were interfered by OH band and Ta matrix,so the scanning spectrogram was relatively complicated,which was disadvantageous to the analysis.In this study,a proper multicomponent spectral fitting（MSF） model was created under the selected Nb 269.706 nm line.The spectral interference of Ta matrix at high content in the determination of trace niobium was effectively corrected.The detection limit of this method was 0.000 9 mg/L.The proposed method was applied to the determination of niobium in tantalum sample,with the RSD of 0.61 % and the recovery rate of 101 %.When this method was used to determine the synthetic sample with known composition（the content of tantalum was less or close to the matrix concentration in MSF model,and the concentration of niobium was higher than 0.500 mg/L）,the relative errors were all smaller than 1.0 %.