Electrochemical sensor for detecting aflatoxin

An aflatoxin and electrochemical technology, applied in the field of biosensors, can solve the problems of poor sensitivity and repeatability of thin-layer chromatography, cumbersome pretreatment steps, and inapplicability for rapid detection, and achieve easy portable and online detection, samples and reagents. The effect of low consumption and large distribution of electroactive sites

Inactive Publication Date: 2020-02-14
INST OF QUALITY STANDARDS & TESTING TECH FOR AGRO PROD OF SHANDONG ACADEMY OF AGRI SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, enzyme-linked immunoassay has good specificity, but needs to prepare specific antibodies, and the false positive is high; large-scale instrument method often needs cumbersome pretreatment steps and expensive instruments, and is not suitable for rapid detection in the field; the sensitivity of thin-layer chromatography and poor repeatability, inaccurate quantification

Method used

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  • Electrochemical sensor for detecting aflatoxin
  • Electrochemical sensor for detecting aflatoxin
  • Electrochemical sensor for detecting aflatoxin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Example 1 Preparation of an electrochemical sensor for detecting aflatoxin based on acetylcholinesterase

[0049] 1. Preparation of electrochemical sensor process steps

[0050] 1) The preparation of Prussian blue-graphene composite: 2ml concentration is that 4mg / ml graphene dispersion is added to 5ml containing 6mg FeCl under room temperature stirring condition 3 ·6H 2 O,8 mg K 3 Fe(CN) 6 , 37mg of KCl in aqueous solution, with HCl to adjust its pH to 1.5. Stir magnetically for 24h. After the mixture was centrifuged and washed several times, it was vacuum-dried at 40° C. for 12 hours to obtain a Prussian blue-graphene composite. Weigh 10 mg of the complex and dissolve it in 0.5 ml of distilled water. The Prussian blue-graphene composite is prepared.

[0051] 2) Preparation of nano-gold-chitosan composite: at first, utilize sodium citrate to reduce chloroauric acid to synthesize nano-gold particles, the synthetic method is as follows: (1) 100ml double distilled w...

Embodiment 2

[0060] Embodiment 2 detects the optimization of the test condition of aflatoxin

[0061] 1. Experimental steps

[0062] 1) pH is worth optimizing

[0063] Different pH values ​​of the test bottom solution have different effects on the activity of acetylcholinesterase, which in turn will affect the sensitivity of the AuNps / CS / PB / GR / SPCE sensor. Therefore, a series of phosphate buffer solutions with pH values ​​were prepared in this experiment. The pH values ​​were 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, and 9.0, respectively, and a series of 1.5mmol / L ATC1 bottom solutions were prepared respectively.

[0064] 2) Optimization of enzyme immobilization amount

[0065] The amount of AChE immobilized on the electrode surface is also one of the important factors affecting the current response of the biosensor. Figure 6 Shown is the AuNps / CS / PB / GR / SPCE sensor after dropping different amounts of acetylcholinesterase, and the electrode without adding acetylcholinesterase to perform cyclic vol...

Embodiment 3

[0075] Embodiment 3 utilizes the application of prepared amperometric acetylcholinesterase sensor

[0076] 1) Inspection of sensor stability

[0077] The stability of the sensor was studied by the inter-group deviation test. The AuNps / CS / PB / GR / SPCE sensor was fabricated on 5 screen-printed electrodes by the same method, and the aflatoxin of 16 μg / mL was determined. The relative deviation 3.8% respectively, indicating that the AuNps / CS / PB / GR / SPCE sensor has good stable reproducibility;

[0078] 2) Linear relationship between aflatoxin concentration and inhibition rate

[0079] A series of concentrations of aflatoxin standard solutions were prepared, and the above acetylcholinesterase sensor was immersed in different concentrations of aflatoxin standard solutions for 14 minutes, and then phosphoric acid containing 1.5mM thioacetylcholine chloride (ATCl) was added to the reaction cell saline buffer solution for cyclic voltammetry scans, Figure 8 Shown are the cyclic voltammet...

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Abstract

The invention discloses an electrochemical sensor for detecting aflatoxin. The sensor is based on the principle that aflatoxin can be subjected to non-covalent bond combination with an acetylcholin esterase active site to inhibit the activity of the enzyme. The surface of a screen-printed electrode is modified with a prussian blue-graphene compound and a nanogold-chitosan compound; and acetylcholin esterase is dropwise added to the modified electrode, so that the electrochemical sensor capable of detecting aflatoxin is obtained. The sensor has advantages of simple operation, low cost, and highdetection sensitivity. Compared with the traditional detection method, the electrochemical sensor has the following characteristics: the reaction time is short; the sample and reagent consumption islow; the stability is high; portability is high; the sensor can be applied to field detection of actual samples; and the requirements for rapid aflatoxin detection technology development and internationalization in China are met.

Description

technical field [0001] The invention relates to an electrochemical sensor for detecting aflatoxin, belonging to the field of biosensors. Background technique [0002] Aflatoxin (AFs) is a highly toxic mycotoxin with high teratogenicity and mutagenicity. It is ubiquitous in grains, peanuts, corn, cottonseed meal, soybean meal, etc., and it is in the field and storage process can generate aflatoxin. Aflatoxins are classified as Class I carcinogens by the International Agency for Research on Cancer, which are extremely harmful to humans, poultry and livestock. Among them, aflatoxin B1 (AFB1) is the most toxic, and its toxicity is 67 times that of arsenic. [0003] The current detection techniques for aflatoxin include enzyme-linked immunoassay, gas chromatography-mass spectrometry, liquid chromatography, thin-layer chromatography, liquid chromatography-mass spectrometry, etc. Among them, enzyme-linked immunoassay has good specificity, but needs to prepare specific antibodies,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/30G01N27/38G01N27/327G01N27/48
CPCG01N27/308G01N27/3272G01N27/3274G01N27/38G01N27/48
Inventor 董燕婕王怡然赵善仓范丽霞王磊
Owner INST OF QUALITY STANDARDS & TESTING TECH FOR AGRO PROD OF SHANDONG ACADEMY OF AGRI SCI
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