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Glycol reduction at 200 ° C were prepared Fe3O4 microspheres , explore the different materials on the sample morphology and crystallinity , and samples were XRD , IR , TEM and VSM characterization . Experimental results show that : regular morphology of microspheres , good dispersion , high crystallinity, narrow particle size distribution than the saturation magnetization of 89 emu / g . Were used microemulsion method and class St. ? Ber prepared core - shell Fe3O4/SiO2 , composite microspheres , explore the TEOS amount of alcohol-water microspheres morphology, crystallinity and magnetic response of impact , and the samples were XRD, TEM, IR, VSM, XPS, EDS and ICP characterization . The experimental results show that : the regular morphology of the preparation Fe3O4/SiO2 microspheres , the surface is smooth and rich in silanols ; the silica shell magnetic slight impact , but the microspheres still high than the saturation magnetization . 3 . Dispersion polymerization package is the core - shell Fe3O4/PS composite microspheres prepared carboxyl-modified polystyrene (PS) , and explore a variety of factors ( such as lead agent type , the amount of monomer , ultrasound-assisted and stability etc.) on the experimental results , and the samples were XRD , TEM , IR and VSM characterization . The experimental results show that : the sample particle size distribution uniformity , the surface carboxyl group-containing , high degree of crystallinity , having a strong magnetic . The Fe3O4/SiO2 composite microspheres and carboxyl functional Fe3O4/PS composite microspheres , to establish a method of extracting DNA from E. coli and Aspergillus niger . The results showed that : 10mg Fe3O4/SiO2 composite microspheres can be extracted from the 40μL crude E. coli humoral and filamentous fungi Aspergillus niger crude humor 16.3μg plasmid of DNA and 11.0μg chromosomal DNA ; the 10 mg carboxyl-modified Fe3O4/PS composite the microspheres can be extracted from the 40μL of E. coli crude humoral and filamentous fungi Aspergillus niger crude humor out the 13.0μg of plasmid DNA and of 10.7μg chromosomal DNA , and the DNA samples were extracted by agarose gel electrophoresis and UV spectroscopy . The results showed that the isolated DNA samples from the two magnetic composite microspheres were higher purity ( A260/A280 gt ; 1.7 ) .
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