Metrological assessment of the high-accuracy RNAA method for determination of cobalt in biological materials

Abstract

The paper summarizes work on the development of the high-accuracy RNAA method for the determination of trace amounts of cobalt in biological materials. The method is based on a combination of neutron activation with selective and quantitative isolation of the analyte in a state of high radiochemical purity by use of column chromatography followed by gamma-ray spectrometric measurements. The method was devised according to a set of rules, which were formulated to obtain high accuracy of the method. The procedure has been also equipped with several criteria as key factors in quality assurance. Qualification of the high-accuracy RNAA method as a primary ratio method has been demonstrated and its usefulness in the certification of the candidate reference materials tea leaves and mixed Polish herbs is presented.

Ratio primary reference measurement procedure (RPRMP) for the determination of iron in biological materials by RNAA

“…2) has been calculated. The details of evaluation of standard uncertainties associated with individual sources of uncertainty [18] have been described earlier [20,32,33]. The full budget of uncertainty for the iron determination in CTA-OTL-1 is presented in Table 4.…”

“…Neutron activation analysis (NAA) is a nuclear analytical method which enables determination of several elements with good sensitivity, irrespective of their chemical form, nature of chemical bond, oxidation state etc., and in addition it has a unique feature of being practically free from blank Advantages of NAA and its significance in metrology are well known and were discussed in several papers [18][19][20]. Purely instrumental NAA (INAA) has the potential of yielding very accurate results but there is always some additional uncertainty stemming from Compton background, undetected spectral interferences, dead time and pile up effects etc.…”

“…The utmost of the NAA method in terms of accuracy, precision and detection limit can be achieved by combining neutron activation with the selective and quantitative post-irradiation isolation of the desired radionuclide by column chromatography, followed by γ -ray spectrometric measurement. This was the idea of definitive methods by radiochemical NAA (RNAA) [21,22] which fulfil [20,22] the definition of the ratio primary reference measurement procedures (RPRMP) as defined in the recently issued ISO document [23]. In this paper a novel RPRMP for the determination of Fe in biological materials was devised, validated by the analysis of several CRMs and used in an attempt to resolve the mystery of widely discordant results by various analytical techniques in tobacco leaves obtained in worldwide intercomparisons.…”

Determination of chromium in biological materials by radiochemical neutron activation analysis (RNAA) using manganese dioxide

“…RNAA is a combination of neutron activation with a post-irradiation separation of the determined element and gamma-ray spectrometry measurement [ 12 , 13 , 17 , 18 ]. This method was used for the development of the ratio primary reference measurement procedures for the determination of cadmium, cobalt, nickel, molybdenum, uranium, iron, arsenic and selenium in biological materials [ 17 – 21 ].…”