Suitability of NAA for certification of reference materials for multielements

Certifications of trace elements in existing CRMs, especially biological CR Ms, are far from satisfactory. Neutron activation analysis (NAA) for its in herent advantages combined with newly established parametric standardizatio n, may contribute to improve this situation. The continuing progress of the hybrid extended k(0)-relative NAA technique developed in our laboratory is discussed. Examples are given to show the reliability of the method in cer tification of multielements. RNAA is still one of the best methods, or even the method of choice, in analysis at sub-mu g/g concentration levels. The suitability of the technique for this purpose has been studied through the determination of rare earth elements at ng/g concentration level in two Chi nese biological CRMs using both RNAA and ICPMS. Sampling behaviors of multi elements in CRMs have been studied by INAA in an effort to develop CRMs sui table for analysis with small sample sizes.