电感耦合等离子体原子发射光谱法测定高温合金和耐热不锈钢中铌时钒、钛、铬的光谱干扰及校正

与一般在试液中加入可疑干扰元素的离子标准溶液来考察干扰元素和干扰程度的方法不同,本文用含不同铌且基体及组分元素差异较大的化学标准物质配制标准溶液,并根据用其测定铌时各相关分析线的校正曲线成线性情况,考察测定铌的光谱干扰程度。实验结果表明:标准溶液中钒、钛和铬对测铌的不同分析线存在干扰,尤以钒、钛分别对Nb309.418 nm和Nb313.079 nm干扰为甚,严重影响测量结果的准确度。采用干扰系数法校正光谱干扰以后,各分析线的校正曲线线性相关性大大提高,从而提高了测量结果的准确度。校正了钛对Nb313.079 nm的光谱干扰后,测得的GH4169化学标钢中的铌量为5.21%±0.060%与标钢赋值5.22%相一致。同时通过对校正后铌的各分析校准曲线线性的分析研究,找到了Cr18Ni20Mo2Cu2Nb不锈钢中铌测定值偏低的原因。

Spectral interference and correction of vanadium,titanium and chromium during the determination of niobium in high temperature alloy and heat-resistance stainless steel by inductively coupled plasma atomic emission spectrometry

In common methods, the standard solution of suspicious interference elements was usually added into sample solution to investigate the interference elements and interference level. In this study, the standard solution was prepared by reference materials containing different amounts of niobium and larger difference of matrix and composition elements. According to the linearity of calibration curves of analytical lines, which were obtained during the determination of niobium using standard solution prepared, the spectral interference level in the determination of niobium was investigated. The results showed that, vanadium, titanium and chromium in standard solution had interference to different analytical lines of niobium. The interference of vanadium and titanium to Nb309.418 nm and Nb313.079 nm was most serious, greatly influencing on the accuracy of determination results. After correction of spectral interference by interference coefficient method, the linearity of calibration curves of analytical lines was significantly improved. Thus, the accuracy of determination results was enhanced. After modifying the spectral interference of titanium to Nb313.079 nm, the measured content of niobium in GH4169 steel was 5.21%±0.060%, which was consistent with the certified value 5.22%. By analysis and study of linearity of calibration curves of analytical lines after correction, the reason of lower determination results of niobium in Cr18Ni20Mo2Cu2Nb stainless steel was found.