Quantitative calibration and quality control have been a major bottleneck in microanalysis due to the lack of natural-matrix
CRMs certified at sample sizes compatible with those of unknown samples. In this paper, a solution is described to characterize
sampling behavior for individual elements, so as to identify elements homogeneous enough at stated sample size levels in given
CRMs/RMs. By using a combination of several nuclear analytical techniques, INAA-EDXRF-µPIXE, sampling behavior for individual
elements can be characterized at sample size levels from grams down to pg. Natural-matrix CRMs specifically for QC of microanalysis
may thus be created. Additional information in certificates of these new generation CRMs is imagined.