A Newly Designed Adsorbent Prepared from Hydroxyapatite Originating from Cattle-Bones for Chromatographic Separation of Albumin and Lysozyme

Functional spherical particles 5—30 μm in size were prepared by a spray-drying method with ultrasonic dispersion from hydroxyapatite (r-HAp) which was derived from bones of cattle. The liquid chromatographic characteristics for the separation of bovine serum albumin (BSA) and lysozyme from egg white (LSZ) on the r-HAp particles were investigated in comparison with those of stoichiometric hydroxyapatite (s-HAp) derived from reagents. The specific surface area (SAD), the crystallite size (CS), and the microstructure of the HAp’s particles were strongly influenced by the heat-treatment at 273—1073 K (designated by HAp(273—1073)) in a stream of water vapor. In liquid chromatography (LC) analysis with columns packed with the HAp powders, for r-HAp, mixed solutions of 0.5—2.0 mg cm−3BSA and LSZ were sufficiently eluted using a linear molarity gradient of sodium phosphate buffers at 313 K. The resolutions (RS) of the proteins and the widths for each half of the chromatographic curves (WHBfor BSA or WHLfor LSZ) were sensitively varied in connection with SADand CS. The optimal values of the LC operating parameters for all the HAp’s were evaluated as RSof r-HAp(673) and WHBand WHLof r-HAp(873).