Preparation And Property Investigation Of Fe₃o₄ And Fe₃o₄ @ Gd₂o₃:eu Labeling Nanoparticles

In the research of the chemistry, biomedical science and the biologic technology, the molecular probe used for biologic identification has already been applied in the research of biologic function and super sensitive detection of many diseases. Along with the development of the modern biologic technology, many labeling methods appear, for example, luminescence labeling technology and magnetic labeling technology etc.,which are very promising labeling technique and have already been applied in commerce owing to their excellent properties of sensitivity, stability, security and low cost. In this experiment, Fe3O4@Gd2O3:Eu core shell labeling particles were prepared which possess the virtue of both magnetic label and luminescence label.Gd2O3:Eu powders were synthesized by homogeneous coprecipitation method and Hexamethylenetetraamine, (CH2)6N4, was used as precipitator. Taking rare-earth nitrate and rare-earth chloride as the raw material, Gd2O3 phase can be obtained by calcined the precursor at 800℃.Gd2O3 particles synthesized from the raw material of rare-earth nitrate are apt to from big laminar crystals but that from rare-earth chloride are spheric shape. Taking rare-earth sulphate as the raw material, the products easily grow into spheroid and increasing the ratio of Gd 3+:SO42- can effectively reduce the particle size. To obtain the Gd2O3 phase,1200℃calcination temperature are required.Gd2O3:Eu nanoparticles were synthesized with a homogeneous coprecipitation method using urea as precipitator. Whether taking rare-earth sulphate as raw material, or the intermixture of the rare-earth nitrate and the rare-earth sulphate as raw material, spheroid and uniform particles were obtained. The particle size is reduced with the increasing of Gd3+:SO42 ratios. The luminescence intensity of Gd3+:SO42-=1:0.8 is stronger than the intensity of Gd3+ SO42-=1:0.2.Compared to (CH2)6N4 as precipitator, the same Gd2O2SO4 phase was detected under the calcined temperature from 800-1000℃,and calcined at 1200℃,Gd2O3 phase appeared. The Gd2O3 crystallization degree is enhanced and crystal symmetry is strengthened by taking urea as precipitator. The Gd2O3:Eu particles grow smaller by taking urea as precipitator than (CH2)6N4 as precipitator.Fe3O4 nano powder was synthesized with coprecipitation technique with NaOH as precipitator. Taking saturation magnetization as main review factor, the optimized processing parameters of preparing the Fe3O4 powder is that the iron ion concentration 0.2 mol/1, alkali concentration 0.2 mol/l, the temperature 70℃and the ratio of Fe3+:Fe2+ 1.8.The shape of Fe3O4 particles are spheroid, the size is about 20 nm, the coercive force is small, and hysteresis effect is weak. In the process of preparing Fe3O4@SiO2@Gd2O3:Eu core shell particles, increasing the ratio of Gd/Fe spheroid product is easily formed and reducing the ratio of Gd/Fe needle-shaped particles formed. The Fe3O4 nucleus lead to luminescent intensity reduced, but the luminescent intensity is enhanced along with the increase of Gd3+: Fe3+ ratio.