Ion Chromatographic Analysis of Hydroxyapatite

Abstract

An ion chromatographic method was developed for the determination of cations and anions in hydroxyapatites. It involved high pressure microwave-assisted acid digestion in closed TFM vessels in order to achieve complete dissolution of samples in less than half an hour. The clear solution resulting from the digestion was diluted, filtered, and directly injected onto an ion chromatograph equipped with a conductivity detector. The method was tested on several apatites and has been found to be satisfactory for the determination of total nitrogen (as nitrate), phosphorus (as phosphate), sulphur (as sulphate), and of lithium, sodium, potassium, magnesium, calcium, strontium, and barium. The accuracy of the proposed method was demonstrated by comparing the results with those obtained by ICP-AES and UV/vis spectrophotometry.

Keywords:

• Anions
• cations
• hydroxyapatite
• ion chromatography
• microwave digestion

Acknowledgments

The authors are grateful to the Biomaterials Group of CNR-ISTEC for generously donating hydroxyapatite materials and to Montaleone Francesco for performing the ICP-AES measurements.

Notes

*mean value ±SD from 10 injections.

*Mean value±SD from five injections.

*Mean value±SD from five determinations