In vitro determination of inorganic constituents in bone tissues using neutron activation analysis

In the past years, there has been an increasing interest in bone analyses since they are deposits of essential and toxic elements. Besides they have supporting function of human body and protect vital organs. Besides, analyses of inorganic constituents in bones have been carried out to study bone diseases such as osteoporosis and tumors in bones. In this work, an adequate experimental procedure was established for bone tissue treatment, and instrumental neutron activation analysis was applied to trace element determinations in freeze-dried cortical and trabecular tissues and whole bone ash from animal (porcine and bovine) and human ribs. Using short and long-period irradiations at the IEA-R1 nuclear research reactor, the elements Ba, Br, Ca, Cl, Fe, K, Mg, Mn, Na, P, Rb, Sb, Sr and Zn were determined in bone tissues. To validate the analytical methodology, biological certified reference materials were analyzed and their results showed good precision and accuracy. Besides analyses of a bovine rib bone presented precise data for most elements with relative standard deviations lower than 14 %. This result demonstrated that the procedure defined for bone tissue treatment was appropriate to obtain homogeneous samples. However, the calcination was not suitable for whole bone treatment due to loss of Br and Cl. Statistical t test was applied to compare the results obtained for different tissues of bone and also the results found for ribs of two animal species. Comparisons between the results obtained for correspondent tissues of porcine and bovine ribs present different element concentration. Moreover, cortical and trabecular tissues of humans presented different concentrations for all the elements analyzed in this work. These findings indicate that trace elements in bone samples have to be separately studied. (author)