Radiochemical Neutron Activation Analysis

Abstract Radiochemical neutron activation analysis (RNAA) is a method for trace‐element determination based on the measurement of an indicator radionuclide, chemically separated from a neutron‐activated sample. Unlike instrumental neutron activation analysis (INAA) the RNAA is therefore not a nondestructive method, and at the same time the amount of work put into the analysis of each sample makes RNAA much more expensive than INAA. This is the cost that has to be paid for determining selected elements at much lower concentrations and superior accuracy, while maintaining matrix independence and most of the other excellent characteristics of INAA. One of these characteristics is the small self‐shielding during irradiation with neutrons, which opens the possibility of analyzing also large samples without any pretreatment. Particularly for the lowest levels of trace elements RNAA provides several important advantages over alternative analytical methods: the absence of a reagent blank, and the corresponding insensitivity to contamination after activation the controlled addition of carrier to avoid losses by adsorption etc., and the corresponding possibility of determining chemical yield or recovery. When carefully and thoughtfully carried out, RNAA qualifies as a so‐called definitive method, one of the reasons being its direct traceability to a comparator of the pure element to be determined.