Preparation method and SERS application of monodispersed silver-shell magnetic microspheres

A technology of magnetic microspheres and monodispersity, which is applied in the field of nanomaterials and biochemical spectral analysis and detection, can solve the problems of poor dispersion and uneven structure of silver-shell magnetic microspheres, and achieve strong magnetic response, uniform structure, and dispersibility Good results

Inactive Publication Date: 2017-02-15
ACADEMY OF MILITARY MEDICAL SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the problems of poor dispersion and non-uniform structure of existing silver-shell magnetic microspheres, and provide a method for preparing silver-shell magnetic microspheres with monodispersity, high magnetic responsiveness, complete silver shell, and uniform structure , and used as a SERS substrate for trace detection of target substances in solution

Method used

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  • Preparation method and SERS application of monodispersed silver-shell magnetic microspheres
  • Preparation method and SERS application of monodispersed silver-shell magnetic microspheres
  • Preparation method and SERS application of monodispersed silver-shell magnetic microspheres

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Embodiment 1

[0037] A preparation of monodisperse silver-shell magnetic microspheres:

[0038] figure 1 A schematic diagram of the preparation process of monodisperse silver-shell magnetic microspheres is given. Its specific preparation method is divided into the following five steps: the first step, using solvothermal synthesis method to synthesize 400nm Fe 3 o 4 Microspheres. Dissolve 2.7 g of ferric chloride hexahydrate in 80 ml of ethylene glycol, and stir magnetically for 30 minutes. Next, 5.4 g of sodium acetate and 2 g of polyethylene glycol 6000 were added to the solution and stirred until the reactants were completely dissolved, then the mixture was transferred to an autoclave (100 ml capacity) with a polytetrafluoroethylene liner and heated to 200 °C for 10 hours. The product was collected with a magnet, washed three times with deionized water and ethanol respectively, and finally the product was vacuum-dried at 60°C for 5 hours to obtain a 400nm Fe 3 o 4 Microspheres are...

Embodiment 2

[0045] SERS performance characterization of monodisperse silver-shell magnetic microspheres:

[0046] PATP was selected as the Raman molecule to characterize the SERS performance of monodisperse silver-shell magnetic microspheres. PATP is a commonly used sulfhydryl Raman marker, and it will produce significant chemically enhanced Raman characteristic peaks when combined with gold or silver. Add the synthesized silver-shell magnetic microspheres to 1ml concentration from 10 -6 -10 -11 The PATP solution was mixed and shaken for 30 minutes. After magnetic separation, the particle concentrate was dispersed on a clean silicon wafer, and Raman detection was performed after drying. image 3 It is a schematic diagram of the application of monodisperse silver-shell magnetic microspheres in SERS detection.

[0047] Figure 4 It is the experimental result of Example 2. exist Figure 4 The middle abscissa is the Raman shift. Figure 4 The curves in the middle are from top to bottom ...

Embodiment 3

[0049] Detection of pesticide thiram in solution by monodisperse silver shell magnetic microspheres:

[0050] Add monodisperse silver-shell magnetic microspheres to thiram aqueous solutions with different concentrations, incubate with ultrasound for 15 minutes, and detect the particles directly with a portable Raman spectrometer after magnetically enriching the particles.

[0051] Figure 5 It is the experimental result of embodiment 3. exist Figure 5 Among them, the curves a, b, c, d, e, and f respectively represent the detection concentration of monodisperse silver-shell magnetic microspheres is 10 -4 、10 -5 、10 -6 、10 -7 、10 -8 and 10 -9 Raman spectra of M thiram, including 561, 928, 1145 and 1385cm -1 The peak is the main characteristic peak of thiram. The experimental results show that the detection limit of thiram by monodisperse silver shell magnetic microspheres is 10 -9 M, with very efficient surface-enhanced Raman functionality.

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Abstract

The invention discloses a preparation method and SERS application of monodispersed silver-shell magnetic microspheres. In a base, 400 nm Fe3O4 microspheres are taken as cores to provide magnetism, 50 nm SiO2 shells are taken as hydrophilic sandwich layers to improve the dispersibility of the microspheres, and complete and uniform silver shells are prepared with chemical plating and seed reduction methods. The preparation method comprises the following steps: enabling the 400 nm Fe3O4 microspheres to be covered with the 50 nm SiO2 shells with an improved Stober method, and then carrying out sensitization on the SiO2 shells through SnCl2, so that a great deal of Sn<2+> are adsorbed; washing the magnetic microspheres with deionized water, after the SnCl2 is completely removed, and using a 40 mM silver-ammonia solution to perform kernelization on Fe3O4@SiO2 under an ultrasonic condition, so that a large quantity of Ag seeds are generated in an in situ manner; finally using a seed growing method, and under high-concentration PVP protection, using formaldehyde and stronger ammonia water to reduce the complete and uniform Ag shells so as to form the monodispersed silver-shell magnetic microspheres. The invention also discloses application of the silver-shell magnetic microspheres prepared through the method in SERS detection, the monodispersed silver-shell magnetic microspheres are high in magnetic responsiveness, good in dispersibility, stable in structure and extremely high in enhancing effect, and can be directly used for SERS detection of various micromolecular pollutants, pesticide residues, serum, cancer biomarkers and the like under a solution system.

Description

technical field [0001] The invention relates to the fields of nanomaterials and biochemical spectrum analysis and detection, in particular to a preparation method of monodisperse silver-shell magnetic microspheres and its application in SERS detection. Background technique [0002] Surface Enhanced Raman Scattering (SERS) is a kind of fingerprint vibration spectroscopy, which has the advantages of high selectivity, high sensitivity and fast non-destructive detection, which has attracted more and more attention and has been successfully used in Biochemical detection, sensors, analytical chemistry and environmental monitoring and other fields. The key to SERS detection lies in high-performance SERS substrates, and all SERS enhancements are limited to SERS substrates developed from precious materials such as gold and silver. At present, the commonly used SERS substrates are mainly divided into two categories: metal particles and planar metal structures. The main advantages of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/09H01F41/02G01N21/65
Inventor 王升启李萍汪崇文肖瑞荣振庞元凤王俊峰曲新燕王靖郭晶
Owner ACADEMY OF MILITARY MEDICAL SCI
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