Rapid melamine determination method using bare gold nanoparticles as developing probe

A technology for rapid determination of melamine, applied in analytical chemistry and nanometer fields, can solve problems such as poor sensitivity, limitation, time-consuming, etc., and achieve the effects of low processing requirements, fast detection speed, and simple and fast preparation process.

Inactive Publication Date: 2012-10-03
FUJIAN MEDICAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Most of these methods show quite high sensitivity, but the complex modification process of gold nanoparticles limits their application to some extent.
The technique of colorimetric detection of melamine during the formation of gold nanoparticles has also been reported, but it is very time-consuming
Simpler methods for the detection of melamine have been established using unmodified AuNPs (actually citric acid-coated AuNPs) as chromogenic probes, but all were less sensitive

Method used

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  • Rapid melamine determination method using bare gold nanoparticles as developing probe
  • Rapid melamine determination method using bare gold nanoparticles as developing probe
  • Rapid melamine determination method using bare gold nanoparticles as developing probe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Preparation of bare gold nanoparticles: First, 500 μL of 0.1 g / L chloroauric acid aqueous solution was diluted with 39.5 ml of water, and 0.8 ml of 0.1 g / L sodium borohydride aqueous solution was added under vigorous stirring (the addition time was controlled at Within 5 minutes), the color of the reaction solution changed from light yellow to wine red, and the dark place continued to stir rapidly for 1 hour. The resulting bare gold nanoparticles have an average particle size of 8.1 ± 1.1 nm (see figure 1 , Picture 1-1 ) wavelength at 518 nm (see figure 2 ), stored at 4 °C, bare gold nanoparticles can be kept for at least two months and are relatively stable. All glassware used in the above process was soaked in aqua regia, washed thoroughly with double distilled water, and dried.

Embodiment 2

[0042] Interaction between melamine and bare gold nanoparticles: Add 0.2 ml of phosphate buffer solution containing 0.1 mg / L melamine to 0.2 ml of bare gold nanoparticles prepared in Example 1 (the concentration of the phosphate buffer solution is 0.01 mol / L, pH=3 ), react at 40°C for 5 minutes. The color of bare gold nanoparticles changes from wine red to blue, and the maximum absorption wavelength is red-shifted (see image 3 ), the aggregated gold nanoparticles can be clearly seen from the TEM image (see Figure 4 ).

Embodiment 3

[0044] Interaction between melamine and bare gold nanoparticles: Add 0.2 ml of phosphate buffer solution containing 0.1 mg / L melamine to 0.2 ml of bare gold nanoparticles prepared in Example 1 (the concentration of the phosphate buffer solution is 0.01 mol / L, pH=3 -12), react at 40 degrees Celsius for 5 minutes, and measure the absorbance ratio A 650 / A 518 . like Figure 5 As shown, the absorbance ratio A 650 / A 518 It reaches a maximum at pH=3.

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Abstract

The invention discloses a rapid melamine determination method using bare gold nanoparticles as a developing probe. The gold nanoparticles are gathered under the action of electrostatic interaction and covalent interaction of AcCl4- / AuC12-ion absorbed on the surface of an exocyclic amino group of melamine and the bare gold nanoparticles, thereby expressing the change of the solution color and the ultraviolet absorption spectrum characteristic. The limit of detection of visual observation is 0.05 mg / L. The detected linear range of the absorbance ratio is 5-200 mu g / L, and the limit of detection is 0.2 mu g / L. After the simple pretreatment, the melamine content in the milk powder sample can be determined by adopting the method.

Description

technical field [0001] The invention relates to a rapid content determination method for melamine using bare nano-gold as a color probe, and belongs to the fields of analytical chemistry and nanotechnology. Background technique [0002] Gold nanoparticles have attracted extensive attention due to their facile preparation and biofunctionalization, excellent biological stability, and unique spectral properties. The surface plasmon absorption bands of gold nanoparticles lie in the visible region of the electromagnetic spectrum and are influenced by the morphology of the nanoaggregates. Typical colloidal gold nanoparticles are wine red, while their aggregates appear purple or blue, which is due to the shift of the surface plasmon absorption band of gold nanoparticles to long wavelengths. Methods based on this principle can be used for the detection of various analytes such as cells, proteins, DNA, and metal ions. [0003] Melamine (1,3,5-triazine-2,4,6-triamine, C 3 h 6 N 6...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/29G01N21/33
Inventor 陈伟邓豪华刘爱林洪磊王胜
Owner FUJIAN MEDICAL UNIV
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