Certified Reference Material for analytical quality assurance of minor andtrace elements in food and related matrixes based on a typical Japanese diet: Interlaboratory study

A Certified Reference Material (CRM) was prepared at the National Institute for Environmental Studies (NIES), Japan, in collaboration with the Nationa l Institute of Radiological Sciences (NIRS), Japan, for the analytical qual ity assurance of minor and trace elements in food and related matrixes. The starting material for the CRM was all food served in 29 households in Japa n over two 3-day periods in 1997-1998, and thus the CRM represented a typic al Japanese diet. All foods (meals, snacks, and beverages) were homogenized , freeze-dried, pulverized, blended, dispensed into 1100 bottles, and steri lized. The within- and between-bottle homogeneity of the prepared CRM was s atisfactory for most of the elements. The concentrations of 14 elements (Na , Mg, K, Ca, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Ba, and U) were certified base d on a collaborative analysis involving NIES, NIRS, and 20 other laboratori es. Reference values were given for the concentrations of 12 additional ele ments (P, Cl, Fe, Co, Ni, Br, Rb, Mo, I, Cs, Pb, and Th). The elements cert ified and those given reference values include minerals, essential trace el ements, contaminant elements, and long-lived radionuclides. Thus, this CRM is of practical value in the quality assurance of element analysis of foods and diets in nutritional, environmental, and radiological research.