Preparation method of ascorbic acid oxidase electrochemical biosensing composite modified electrode

Abstract

The invention relates to a preparation method of an ascorbic acid oxidase electrochemical biosensing composite modified electrode. The preparation method comprises the steps of: preparing an electrolyte solution from 3,4-ethylenedioxy thiophene, sodium lauroylsarcosine, carbon nanotubes and 1-ethyl-3-methylimidazolium ethyl sulfate, and carrying out 1.1V constant-potential polymerization in a three-electrode system for 60 seconds to prepare the conducting poly(3,4-ethylenedioxy thiophene) nano film composite modified electrode by one-step reaction; and then drip-coating ascorbic acid oxidase buffer on the surface of the composite modified electrode, and finally covering the enzyme layer with a mixed liquid of carbon nanotubes, Nafion and ionic liquid. The constructed composite modified electrode has the advantages of good biological electric catalysis activity to vitamin C, wide linear range, low detection potential, rapid current response, significant sensitivity, high repeatability and stability, good selectivity, high immobilized enzyme activity and strong affinity; and the preparation method has the characteristics of low cost, simple process, and simplicity and easiness in operation and the like.

Description

technical field [0001] The invention belongs to the technical field of biosensors, and relates to a preparation method of a composite modified electrode for electrochemical biosensing of ascorbate oxidase. Background technique [0002] Since Foulds and Lowe immobilized glucose oxidase in polypyrrole to construct the first conductive polymer glucose oxidase electrochemical biosensor in 1986, conductive polymers as enzyme immobilization carriers are due to their excellent performance and easy preparation. The advantages of the method and simple operation process are widely favored by biosensor researchers. Conductive polymers used as active molecule immobilization carriers for biosensors have six advantages: ① fast electron transfer capability; ② good biocompatibility with bioactive molecules; ③ able to maintain good biological activity of bioactive molecules; ④ It can effectively prevent the loss of bioactive molecules; ⑤ can prolong the life of the biosensor; ⑥ can reduce t...

AI Technical Summary

Problems solved by technology

[0003] The conductive polymer enzyme electrode prepared by the traditional electrochemical method (the bioelectrode in which the enzyme is immobilized on the surface of the electrochemical electrode by the conductive polymer film) has poor biocompatibility and has certain toxicity to the enzyme (M.Gerard , A.Chaubey, and B. D. Malhotra, Biosens. Bioelectron., 2002, 17, 345)

As a result, problems such as poor stability, poor reproducibility, low sensitivity, high detection limit, and small detection range in the detection process are caused, and the accuracy also has a great impact in practical applications.

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