Development of Instrumental Neutron Activation Analysis Methods for Assessment of Iodine and Selected Elements in Ghanaian Foods Using Low Power Research Reactors

Abstract

Various types of instrumental neutron activation analysis (INAA) method were developed for the determination of Iodine and 30 major, minor, and trace elements in samples of Ghanaian foods. Most of the elements were analysed by conventional INAA with anticoincidence counting. A number of INAA methods were evaluated for selenium and iodine determinations. The methods included: conventional and Pseudo-Cyclic TNAA (PCINAA) with Compton suppression gamma-ray spectrometry for selenium. The INAA methods developed for iodine determinations were Conventional Flux and Epithermal INAA (EINAA) using Compton suppression gamma-ray spectrometry. The relative method of standardization was used for quantification of all the elements. Additionally, quantification 01' iodine and some selected elements was carried out using ko- NAA standardisation method. The Nisle unified formulation was investigated for the ko-NAA method and compared with the well known Hogdahl convention and Westcott formalism. Precision and accuracy were evaluated through the analysis of standard reference materials (SRMs). The measured values were found to be in good agreement with the certified values; generally, within ± I0%. Detection limits were calculated and found to vary from 1.0 ng.kg·\ for antimony and gold to 400 mg.kg-1 for sulphur. The overall uncertainty associated with the measurement of Iodine using both the relative and the ko methods of standardization were evaluated. In general, most of the Ghanaian food items were found to contain the required concentration of iodine and other elements of nut6tiol1al importance.