Study of enrichment of calcium isotopes in biological samples

The calcium is an important chemical element for propping up the skeleton's of lives. If calcium is run off from the living creatures, osteoporosis and bone fracture will be fallen. Now the rate of these diseases is already the seventh of the common disease in the world. Obviously, the study on the concentration of calcium and its metabolism in vivo is very important. The calcium contains seven stabile isotopes in nature. Their abundances are 96.941% for 40Ca, and 0.647%, 0.135%, 2.086%, 0.004% and 0.187% for 42Ca, 43Ca, 44Ca, 46Ca and 48Ca respectively. The difference of atomic weight between 40Ca and 48Ca is about 20%. The isotope discrimination of Ca in animal bones is observed. The samples of skull, rib, leg bones of rats are digested by HNO3 + H2O2, then analyzed by ICP-MS. The results show there are isotope ratio differences of calcium between the samples taken from different parts, indicating that the isotope discrimination of Ca may play important roles in bodies. Further studies on the calcium isotope ratios of different skeletons from different animal models or some diseases will be carried out by ICP-MS. (authors)