超纯氧化铁制备及其在电感耦合等离子体原子发射光谱法测定高纯铁化合物中杂质元素的应用研究

用电感耦合等离子体原子发射光谱法(ICP-AES)准确测定高纯铁化合物中的痕量杂质元素，需要更高纯度的铁作为基体，以研究它对测定杂质元素的干扰。为此，以分析纯硫酸亚铁为原料制备了高纯氧化铁，制得的高纯氧化铁中杂质元素Al、Cd、Co、Cr、Cu、Mg、Mn、Ni和Zn等的含量低于方法检出限。用制备的高纯氧化铁作为标准系列溶液的基体，得到了基体匹配的标准系列溶液，用此标准系列溶液绘制的校准曲线测定了GBW01402d高纯铁标准物质中杂质元素的含量，其测定值与认定值一致。研究了用无基体匹配标准溶液测定高纯铁及铁化合物中Al、Cd、Co、Cr、Cu、Mg、Mn、Ni和Zn等杂质时的干扰校正方法，结果表明:Al、Co、Cr、Cu、Mg和Zn受到的光谱干扰仅需采用离峰法校正即可，而Cd、Mn和Ni受到的光谱干扰则必需采用多元光谱拟合法校正。用拟定的校正方法测定高纯铁化合物中的痕量杂质元素，准确度高的元素有Al、Cd、Cr和Cu，准确度稍差的元素有Co、Mg、Mn、Ni和Zn。

Study on preparation of ultra-pure iron oxide and its application in determination of impurity elements in high-purity iron compounds by inductively coupled plasma atomic emission spectrometry

Accurate determination of trace impurity elements in high purity iron compounds by inductively coupled plasma atomic emission spectrometry (ICP-AES) requires the use of a higher purity iron as matrix to examine its interference in the determination of impurity elements. Therefore,analytical pure ferrous sulfate was taken as a raw material to obtain high-purity iron oxide in which impurity elements Al,Cd,Co,Cr,Cu,Mg,Mn,Ni and Zn were all below the detection limit. The high-purity iron oxide was used as the matrix of a series of standard solutions to obtain matrix-matched standard solutions which were then used to plot the calibration curve,with which the contents of impurity elements of GBW01402d high-purity iron certified reference material were determined,and its found that the measured values of the impurity elements were consistent with their certified values. The interference correction method was studied for the determination of Al,Cd,Co,Cr,Cu,Mg,Mn,Ni and Zn impurities in high-purity iron and iron compounds with non-matrix-matched standard solutions and the results showed that the spectral interference with Al,Co,Cr,Cu,Mg and Zn could be corrected by the off-peak correction method,while the interference with Cd,Mn and Ni necessitated the multicomponent spectral fitting for correction. The proposed correction method was applied to the determination of trace impurities in high-purity iron compounds,with high accuracy for the elements Al,Cd,Cr,Cu and somewhat less accurate for the elements Co,Mg,Mn,Ni,Zn.