Instrumental neutron activation analysis of biological materials using research reactors at BARC

Instrumental neutron activation analysis (INAA) is a reference analytical technique and is extensively used for multielement analysis of reference materials and various samples. Use of high flux research reactors and high efficiency HPGe detector systems enhance the capability of INAA in terms of sensitivity as well as detection limit for many elements. We have standardized the k0-based NAA method in our laboratory for multielement analysis using gold as the single comparator. Neutron spectra at E8 position of Apsara reactor and tray rod position of Dhruva reactor, Trombay, BARC have been characterized by determining epithermal neutron flux shape factor (α) and sub-cadmium to epithermal neutron flux ratio (f). We have used both relative and k0 methods of INAA for determining elemental concentrations of four biological standard/certified reference materials (SRM/ CRM) namely NIST SRMs 1515, 1573a and 1549 and IAEA CRM V-10. The % deviations were found to be within ±10% for most of the elements analysed. The INAA methods were used for multielement determination in five samples of total extracts of processed medicinal plants with an aim to correlating the mineral content with the curative values. These elements analysed in these samples included Na, K, Mn, Mg, Ca, Cl, Br, V, Zn, Co, Se, Sc, Eu, Cs and Ag. The elements were determined via short, medium and long durations of irradiations. Short lived nuclides were measured using pneumatic carrier facility (PCF) at Dhruva reactor whereas for medium and long lived nuclides both Apsara and tray rod facility of Dhruva reactors have been used. The detection limits for the elements analysed in extracts samples were calculated. (author)