Determinatioii of trace elements in reference material Mussel by instrumental neutron activation analysis

Abstract

Concentration of trace elements in an environmental reference material Mussel prepared by National Institute for Environmental Studies (NIES) has been determined by instrumental neutron activation analysis. The Mussel samples (ca. 50~250 mg) were irradiated for 2 min (pneumatic transfer) at a thermal neutron flux of 1.5 X 10 12 n cm -2 s -1 and then for 5 h(central thimble) at thermal neutron flux of 3.2 X 10 12 cm-2 s-1 in Musashi Institute of Technology Research Reactor (MITRR). The gamma-ray measurements of 2 min irradiation samples were performed for 5 min intervals after 1 min cooling and for 4~27 min after 12~80 min cooling using a Ge (Li) detector coupled to a 4096 channel multichannel analyzer. The gamma-ray spectra from 5 h irradiation samples were obtained by measuring samples for 3~14 h after 4~8 d cooling period and for 14~45 h after 15~50 d cooling. Peak-fitting procedure by a minicomputer system (GAMA system) was applied to analyze gamma-ray spectra. In this work 38 elements (Na, Mg, Al, S, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se, Br, Rb, Sr, Mo, Ag, Cd, Sn, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Ta, Au, Th, U) were quantitatively determined. Special cares were taken for obtaining accurate concentrations of aluminum and magnesium by correcting contributions by interefering nuclear reactions such as 31P(n, α) 27Al and 27Al(n, p)27Mg. Duplicate analyses showed a reasonable reproduciblity for the analytical data of major and trace elements, suggesting that the Mussel is homogeneous enough to be used as a certified reference material. © 1984, The Japan Society for Analytical Chemistry. All rights reserved.