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摘要
In order to conduct more precise measurements on a flame atomic absorption spectrometer (FAAS) with a continuum light source, the authors investigated a simultaneous internal standard method. For this purpose, an FAAS instrument, equipped with a xenon short-arc lamp as the radiation source and a high-resolution echelle monochromator, was employed. Synthetic mixed solutions of mixed nickel (10 mu g mL(-1)) and iron (500 and 1000 mu g mL(-1)) were prepared so that the determination of nickel in steel samples could be carried out. Neighboring spectrum lines of nickel (Ni I 232.003 nm) and iron (Fe I 232.036 nm) were selected, and their atomic absorbances were simultaneously measured for each test solution and sample solution. The matrix iron was employed as an internal standard element for nickel analysis by FAAS. In the proposed method, any variance of the analytical results in the measurement using a test solution could be reduced; in addition, the physical interference in the FAAS measurement by sulfuric acid coexisting in the sample solution could be removed. The amounts of nickel in steel CRMs were determined by a calibration curve method and the proposed method. Analytical values obtained by the both methods agreed with the certified reference values in the CRMs. However, in six or ten replicate measurements by these methods, the relative standard deviation of the analytical values obtained by the proposed method was lower than that by the calibration curve method. Therefore, the simultaneous internal standard method is very useful for improving the analytical precision in measurements with FAAS. Furthermore, it was effective for correcting any long-term drift of the sensitivity in the experimental system.
- 出版日期2015-2
