Determination of niobium in niobium-iron alloy by inductively coupled plasma atomic emission spectrometry

The niobium-iron alloy sample was dissolved with hydrofluoric acid and nitric acid.The content of niobium in hydrofluoric acid medium was directly determined by inductively coupled plasma atomic emission spectrometry(ICP-AES).The influence of matrix iron and coexisting impurities including silicon,titanium,aluminum and tantalum on the matrix effect,spectral interference and background noise in determination was investigated.The dilution ratio of sample and the working conditions of instrument were optimized.The analytical lines with appropriate sensitivity as well as the detection integration and background correction area were selected.Consequently,the detection signal intensity of niobium was controlled at appropriate level to guarantee the good linear range,precision and accuracy level of method.The calibration curve was drawn by matrix matching.Meanwhile,the background correction was conducted synchronously.The detection period was only 10-15 min.The results showed that the linear correlation coefficient of calibration curve was r0.999 5when the mass fraction of niobium was in range of 50%-80%.The proposed method was applied to actual determination,and the relative standard deviation(RSD,n=8)of the determination results for actual niobium-iron alloy sample was not more than 0.2%.The determination results of niobium-iron certified reference materials were consistent with the certified values.The determination results of actual niobium-iron sample were consistent with those obtained by paper chromatography gravimetry.