Determination of trace elements in high purity iron as a certified standard material by instrumental neutron activation analysis

Trace elements in high purity iron certified reference materials, JSS001-4 and JSS003-4, prepared by the Iron and Steel Institute of Japan were determined by instrumental neutron activation analysis (INAA). Five or seven aliquots of each sample (ca. 130-750 mg) were irradiated for a short time (2 min) at a thermal neutron flux of 1.5x1012 n cm-2s-1 (pneumatic transfer) and for a long time (6 h) at a thermal neutron flux of 3.7x1012 n cm-2s-1 (central thimble) in the Rikkyo University Research Reactor. The irradiated samples were measured by conventional γ-ray spectrometry using a coaxial Ge detector, and by anticoincidence γ-ray spectrometry with a coaxial Ge detector and a well-type NaI(Tl) detector. The concentrations of 7 elements (Na, Cl, V, Co, Zn, As, W) in the JSS001-4 and 11 elements (Na, Al, V, Mn, Co, Ni, Cu, As, Mo, Sb, W) in the JSS003-4 were determined by these methods. The determined values were in good agreement with the certified and reference values. The lower limit of determination values for Sm, Ir, Au in the JSS003-4 were 0.1 - 1 ng/g. (author)