The use of definitive methods based on radiochemical neutron activation analysis for the determination of selenium and arsenic in materials used in proficiency testing

Many important aspects of human activities depend on the reliability of the results of chemical measurements. Hence, the problem of quality of analytical results and particularly in trace analysis is very important. In spite of considerable development of all instrumental analytical techniques, the problem of accuracy in inorganic trace analysis still exists. From the comparison of individual instrumental techniques it could be concluded that no technique is an ideal one and each possesses some limitations. This could be seen from results provided during organization of international comparisons aimed at the determination of trace elements in biological matrices. The Institute of Nuclear Chemistry and Technology (INCT) as the producer of certified reference materials is the organizer of open worldwide interlaboratory comparisons. In case of several trace elements, data obtained from participants are not sufficient for assigning the certified values. For one of the last two materials: Corn Flour (INCT-CF-3) only 7 participants out of 92 total have delivered results for Se [16]. Moreover, the spread of results was very substantial (e.g. for Soya Bean Flour (INCT-SBF-4) the results for As varied between 0.22 ng·g–1 and 140 ng·g–1) [17]. The position of neutron activation analysis (NAA) among the analytical techniques is still strong despite some weaknesses like the necessity of having access to a nuclear reactor, long analysis time etc. and NAA is without doubt a valuable method in inorganic trace analysis, especially important in certification of reference materials and solving problems with quality control/quality assurance (QC/QA). The highly accurate (definitive) methods The use of definitive methods based on radiochemical neutron activation analysis for the determination of selenium and arsenic in materials used in proficiency testing Ewelina Chajduk, Halina Polkowska-Motrenko, Rajmund S. Dybczyński