ANALYTICAL CONTROL OF WOLLASTONITE FOR BIOMEDICAL APPLICATIONS BY USEOF ATOMIC-ABSORPTION SPECTROMETRY AND INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY

Preliminary in vitro experiments revealed that wollastonite (CaSiO3) i s a potentially highly bioactive material that forms a hyroxyapatite ( HA) surface layer on exposure to simulated body fluid with an ion conc entration, pH and temperature virtually identical with those of human blood plasma. The formation of the HA layer is an essential requiremen t for an artificial material to be used as bioactive bone substitute, This finding opens up a wide field for biomedical applications of woll astonite, Biomaterials used as implants in the human body require stri ct control of trace elements and of the toxic species specified in Ame rican Society for Testing and Materials F-1185-88 (As, Cd, Hg and Pb) in ceramic hydroxyapatite for surgical implantation. In this work, two types of pseudowollastonite, the high temperature form of wollastonit e, mere analysed by using cold vapour atomic absorption spectrometry a nd hydride generation atomic absorption spectrometry, in order to dete rmine the elements stated in the above-mentioned norm, and inductively coupled plasma atomic emission spectrometry to establish the SiO2/CaO ratio of the two materials and analyse for all other impurities intro duced by the raw materials and by the processes of synthesis, sinterin g and grinding, Barium and Mg were especially prominent in raw materia ls, and Zr, Y, Mg, W, Co and Ni come mainly from the processing.