Development of an iron internal standard method using a molecular beam of phosphorus oxide for determination of nickel in steel samples by continuous source flame atomic absorption spectrometry

This paper suggests an improved internal standard method for the flame atomic absorption spectrometry of nickel in a steel sample. The variation of iron absorption was greatly compatible to that of nickel, and then iron-matching calibration standard solutions were conventionally required for precise analytical results. To correct for a varied concentration of iron in a sample solution, phosphoric acid was added into the solution. The absorption caused by phosphorus oxide was simultaneously measured with the absorptions of nickel and iron by using an atomic absorption spectrometer equipped with a continuous light source and an echelle grating system. The improved method was used to quantify nickel in several steel samples containing about 85 to 98 mass% of iron.