Study on homogeneity of multielements for a stream sediment matrix material with nuclear analytical techniques

Taking advantages of nuclear analytical techniques (NATs) with non-destruction, multielement capability, small and estimable uncertainties over a wide range of sample sizes, the sampling behavior of multielements for a home-made natural matrix material was studied with sample sizes ranging from several hundred mg down to tenths ng, namely nine orders of magnitude, by a combination of three NATs, neutron activation analysis (NAA), proton induced X-ray emission (PIXE) and synchrotron radiation X-ray flurescence (SR-XRF), in an effort to explore a procedure for the development of certified reference materials (CRMs) suitable for quality control of microanalysis. For accurately weighable sample sizes (>1 mg), sampling uncertainties for 13 elements were found to be less than 1% by INAA. For sample sizes unable to be accurately weighed (<1 mg), PIXE and SR-XRF were used, respectively. Sampling uncertainties were found to be less than 1% at sample sizes of tenth mg level for seven elements, and less than 10% on ng levels for three elements. Considering these three elements have satisfied homogeneity (sampling uncertainty less than 10%) at ng sample size level, any one of them can be served as a “relative balance” in sampling behavior characterization of multielements on sample size levels larger than ng (e.g., μg level). On this basis, sampling uncertainties for nine elements were found to be less than 10% on μg sample size level by INAA. The results indicate that the matrix is eligible as a candidate of CRMs suitable for quality control of solid sampling microanalysis.