Multielement certification analysis by instrumental neutron activation analysis requires simultaneous irradiation of several elemental comparator standards in order to ascertain traceability. Internal consistency of different comparators may be checked by calculation of k0-ratios, which show large deviations from unity in case of stoichiometric or other gross errors. Quality assurance based on the Analysis of Precision of k0-ratios from replicate analyses detects unexpected variability associated with inaccurate comparator standards. In two actual cases of cerification lack of statistical control among k0-ratios led to biased analytical results.
Journal of Radioanalytical and Nuclear Chemistry, 1994, Vol 179, Issue 1, p. 87-91