| 摘要 |
PURPOSE:To improve magnetic response, dispersion stability and affinity to a biological material by adding FeCl3 and dextran to a mixture solution of CoCl2, FeCl2 and ZnCl2 and adding NaOH dropwise thereto under stirring. CONSTITUTION:To a mixture solution composed of 40 to 70wt.% Co, 10 to 25wt.% Zn and Fe and composed of 0.01 to 0.1mol/l CoCl2, FeCl2 and ZnCl2, an equal amount of an FeCl3 solution with two time the concentration is added. Dextran is added to the resultant mixture solution so as to prepare an aqueous dextran solution of 0.5 to 15wt.%. NaOH is then added dropwise to the prepared solution under stirring so as to complete a coprecipitation reaction at pH 12 to 13. The resultant liquid is subsequently diluted with distilled water and stirred and only dispersed materials floating in the solution are recovered. The recovered reactional products except fine dextran-coated ferrite particles are then removed by ultrafiltration or get-filtration, thus producing the objective fine dextran-coated magnetic particles for marking a biological material, composed of a (Co-Fe-Zn).Fe3O4 ferrite fine particles and having 5 to 10nm crystal grain diameter. |
