Multicomponent internal standard methods for determination of vanadium, chromium, nickel, and copper in tool steel samples in continuum-light-source flame atomic absorption spectrometry

This paper suggests an improved method for the sample preparation to quantify vanadium, chromium, nickel and copper in tool steel and high-speed steel by using flame atomic absorption spectrometry. The suggested method prepared two specimen solutions containing different internal standard elements: one included nickel for the quantifications of vanadium or copper and cobalt for the quantification of chromium and another included cobalt and phosphoric acid for the quantification of nickel, after the sample was digested with an acid mixture of hydrofluoric acid, nitric acid and phosphoric acid by using a microwave oven. A multi-wavelength high-resolution spectrometer system was employed to be simultaneously measured absorption lines for several pairs of an analyte and an internal standard element, such as vanadium and nickel, chromium and cobalt, nickel and iron, cobalt and phosphorus oxide, and copper and nickel. The internal standards contributed to more accurate and precise quantification of vanadium, chromium, nickel, and copper in tool steel and high-speed steel samples.