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Ferromagnetic microsphere medium made from urea-formaldehyde resin and its preparation method

A technology of urea-formaldehyde resin and magnetic microspheres, which is applied in the field of ferromagnetic urea-formaldehyde resin microspheres and its preparation, can solve the problems of non-redispersion, different sedimentation speeds, and difficult separation, so as to avoid poisoning, uniform sedimentation speed, and raw materials low cost effect

Inactive Publication Date: 2004-03-10
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Such hydrophilic magnetic particles have different sedimentation velocities in a magnetic field, making separation difficult; another problem is that Fe 3 o 4 The powder is exposed, which may cause toxic effects on cells; another problem is due to the use of larger particles of Fe 3 o 4 Magnetic powder, even after the external magnetic field is removed, the residual magnetism of the magnetic polymer particles still aggregates together and cannot be redispersed in the solution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Preparation of ferrofluid

[0023] Dissolve 112.8g FeCl respectively 3 .6H 2 O, 41.2 g FeCl 2 .4H 2 O in 100ml of water, pour it into 800ml of water, put the mixed salt solution in an ice bath, cool to 6°C, add 200ml of 28% ammonium hydroxide under stirring, while keeping the temperature at 6°C, the reaction produces black ferric hydroxide Homogenize, heat to 90°C, and keep for 30 minutes, ferric hydroxide will be transformed into ferric oxide precipitate. The reaction equation is as follows:

[0024] Reactant is cooled to room temperature, ferric hydroxide homogenate is transferred in the beaker, is placed on the magnetic separation device, discards clear liquid, redisperses in 800ml deionized water, adds 112ml 60% (by weight) in the homogenate after washing ) of perchloric acid, stirred for 10min, and collected the upper layer of magnetic fluid on the magnetic separation device; the remaining homogenate was redispersed in 500ml of deionized water, and 81ml ...

Embodiment 2

[0029] Embodiment 2: the preparation of magnetic fluid

[0030] Dissolve 5.6g FeCl respectively 3 .6H 2 O, 1.98g FeCl 2 .4H 2 O in 50ml of water, add 10ml of 28% ammonium hydroxide under stirring, and react to generate black ferric hydroxide homogenate. Heat to 60°C for 30 minutes, cool the reactants to room temperature, transfer the ferric hydroxide homogenate to a beaker, pass through a magnetic separation device, discard the clear liquid, redisperse and wash the homogenate three times with 50ml deionized water, and Concentrated nitric acid was added to the slurry to adjust the pH to 1-3, and the slurry was stirred rapidly for 30 minutes to obtain a magnetic fluid. Preparation of magnetic microspheres

[0031] Take 30ml of the above-mentioned magnetic fluid, add 0.3g of SDS powder and 3g of urea under stirring until completely dissolved. Add concentrated perchloric acid to adjust the pH of the mixture to 2-2.5, then add 4ml of 37% formaldehyde solution, stir vigorously...

Embodiment 3

[0033] Take 10g polyethylene glycol and dissolve in 75ml water, add 8.41g FeCl respectively 3 .6H 2 O, 3.05 g FeCl 2 .4H 2 O in 50ml of water, add 15ml of 28% ammonium hydroxide under stirring, and react to generate black ferric hydroxide homogenate. Heat to 60°C for 30 minutes, cool the reactants to room temperature, transfer the ferric hydroxide homogenate to a beaker, pass through a magnetic separation device, discard the clear liquid, redisperse and wash the homogenate three times with 50ml deionized water, and Concentrated nitric acid was added to the slurry to adjust the pH to 1-3, and the slurry was stirred rapidly for 30 minutes to obtain a magnetic fluid. Preparation of magnetic microspheres

[0034] Take 40ml of the above-mentioned magnetic fluid, and add 2.5g of urea under stirring until completely dissolved. Add concentrated perchloric acid to adjust the pH of the mixture to 1-2, then add 7ml of 37% formaldehyde solution, stir vigorously for 20s, then reduce t...

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Abstract

A microspherical medium of ferromagnetic urea-formaldehyde resin is composed of the urea-formaldehyde resin with 0.5-20 microns of granularity and uniformly dispersed Fe3O4 nanoparticles (0.1-200 nm). Its preparing process includes preparing magnetic fluid, preparing its sol, separating and preparing magnetic microspheres. Its advantages are simple and easily controllable process and high stability.

Description

technical field [0001] The invention relates to a ferromagnetic urea-formaldehyde resin microsphere medium and a preparation method thereof, belonging to the technology of magnetic resin microsphere medium. Background technique [0002] Biomagnetic separation technology has the characteristics of simple equipment, low production cost, convenient use and easy automation. It plays an increasingly important role in the fields of biotechnology, biomedical diagnosis, environmental and food analysis. For example, magnetic particles bound to the surface of antibodies, so-called "immune magnetic beads", can be used for the rapid separation of cells in blood and the separation and enrichment of stem cells in bone marrow; magnetic particles bound to the surface of nucleic acid fragment Oligo-dT can be used for the enrichment of mRNA and recovery; while the surface-bound magnetic particles of Streptavidin can be combined with polymerase chain reaction (PCR) and applied to DNA solid-ph...

Claims

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Application Information

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IPC IPC(8): C08G12/12C08K3/08
Inventor 万谦宏陈磊李文斌张志超
Owner TIANJIN UNIV
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