Electrochemical immunosensor for measuring melamine content, preparation method and application

An immunosensor, melamine technology, applied in the field of food safety detection and analytical chemistry, to achieve the effect of high sensitivity and specificity, simple detection method and efficient measurement

Inactive Publication Date: 2011-11-30
NANJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The traditional detection methods of melamine include gravimetric method, sublimation method, etc., but only limited to

Method used

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  • Electrochemical immunosensor for measuring melamine content, preparation method and application
  • Electrochemical immunosensor for measuring melamine content, preparation method and application
  • Electrochemical immunosensor for measuring melamine content, preparation method and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Embodiment 1 Immunosensor preparation

[0051] An electrochemical immunosensor for detecting melamine is obtained by modifying a graphene-melamine-chitosan compound on the surface of a glassy carbon electrode.

[0052] Its preparation method is as follows:

[0053] 1) The preparation of graphene mainly uses graphite oxide (GO) as a precursor, and graphene with excellent properties is obtained through the reduction of graphite oxide and the functionalization of graphene.

[0054] Preparation of graphite oxide: 50 mL concentrated H 2 SO 4 +10 g K 2 S 2 o 8 +10 gP 2 o 5 Mixed, 12 g of graphite powder was added to the above mixed solution, and reacted for 6 h. Add 2 L of water and leave overnight. 460 mL concentrated H 2 SO 4 (refrigerator freezing treatment), the oxidized graphite powder was added to the concentrated H 2 SO 4 Stir in. Control the temperature below 10 ℃, slowly add 60 g KMnO 4 , the mixture was reacted at 35 °C for 2 h, 920 mL of deionized wa...

Embodiment 2

[0061] Example 2 Modified electrode cyclic voltammetry scan

[0062] Cyclic voltammetry studies on different modified electrodes, the results are as follows Figure 4 .

[0063] Bare electrode (curve a) at 2 mM K 3 [Fe(CN) 6 ] The cyclic voltammetry curves in solution show a pair of distinct Fe(CN) 6 3- / 4- Redox peak, the oxidation peak current value is 11.1 μA; when only the chitosan solution is modified on the electrode (curve b), the redox peak potential difference becomes wider, and the peak current decreases at the same time, the oxidation peak current value is 9.931 μA, which may It is because the electrochemically inactive chitosan on the electrode surface hinders electron transfer; when the electrode is modified with graphene / melamine / chitosan (curve c), the peak current increases significantly, and the oxidation peak current value is 21.71 μA, the excellent electrochemical activity of graphene greatly enhanced the transfer of electrons; after the graphene / melamin...

Embodiment 3

[0065] Example 3 Detection condition optimization

[0066] The effect of different detection conditions, such as the time of immune response and antibody concentration, was determined by the DPV method.

[0067] 1. Immune response time

[0068] The immunosensor prepared in Example 1 was incubated with the incubation solution containing the same antibody concentration for 0, 10, 20, 40 and 60 minutes, respectively, and then washed with PBS. 3 [Fe(CN) 6 ] solution in a differential pulse voltammetry (DPV) scan, the results are as follows Figure 5 . The DPV peak current of the graphene / melamine / chitosan modified electrode (immunosensor) decreased rapidly within 40 minutes as the incubation time increased, and decreased slightly at 60 minutes ( Figure 5 ). Further increases in incubation time had no apparent effect on the current response. Therefore, 40 min was chosen as the optimal incubation time for the immune response.

[0069] 2. Effect of antibody concentration in i...

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Abstract

The invention discloses a label-free electrochemical immunosensor for melamine content determination, and a preparation method and application thereof. The immunosensor comprises a substrate electrode, wherein the surface of the substrate electrode is modified by a graphene-melamine-chitosan composite, and nonspecific active sites are sealed by bovine serum proteins. The method for preparing the electrochemical immunosensor is implemented by fixing melamine antigens on the surface of a glass carbon electrode with graphene/chitosan composite materials. Based on an immunoreactive competition mode, the electrochemical immunosensor monitors immune reaction through cyclic voltammetry and differential pulse voltammetry by taking K3Fe(CN)6 as a probe,, and can be used for melamine content detection. The immunosensor disclosed by the invention is high in sensitivity and specificity, simple in detection method and wide in application range; the limit of detection can reach 0.2 ng/ml, and the linear range is 5-1500 ng/ml; and the immunosensor has the characteristics of high speed, high efficiency, high sensitivity, good specificity, simple operation, low cost and the like.

Description

technical field [0001] The invention belongs to the technical field of food safety detection and analytical chemistry, and relates to a detection device and method for melamine, in particular to an electrochemical immunosensor for measuring melamine, a prohibited additive in food and feed, and a preparation method thereof, and A method for quantitatively detecting melamine content using the sensor. Background technique [0002] Melamine is an important chemical raw material. It is often used to make melamine resin, a fire-resistant and flame-retardant material. It can also be used as a water reducer and formaldehyde cleaner. In some Asian countries, it is also used to make fertilizers. Since the protein content detection method "Kjeldahl method" commonly used in the milk and feed industry is to estimate the protein content by measuring the nitrogen content, the average nitrogen content of the protein is required to be about 16%, while the nitrogen content of melamine is abou...

Claims

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Application Information

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IPC IPC(8): G01N27/327G01N27/48G01N33/53
Inventor 赵波陈昌云邵科峰颜妍
Owner NANJING NORMAL UNIVERSITY
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