An L-tyrosine electrochemical sensing electrode based on cubic CoFe-based Prussian blue

Abstract

The present invention belongs to the field of electrochemical sensor technology, and specifically relates to an electrochemical sensing electrode based on a cubic CoFe-type Prussian blue-doped cobalt-iron-nitrogen carbon nanocomposite. The present invention aims to address the problems of narrow detection range, low sensitivity, and poor stability of sensors currently used to detect L-tyrosine. The electrochemical sensing electrode comprises a glassy carbon electrode (GCE) and a cubic CoFe-type Prussian blue-doped cobalt-iron-nitrogen carbon nanocomposite wrapped around the GCE; the electrochemical sensing electrode has excellent detection performance for L-tyrosine.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical sensors, and particularly relates to an electrochemical sensing electrode based on a cobalt-iron-nitrogen-doped carbon nanocomposite of cubic CoFe-based Prussian blue. Background Art

[0002] L-Tyrosine (L-Tyr) is an important essential amino acid for nutrition, mainly used for synthesizing substances such as thyroxine, norepinephrine, dopamine, and melanin, and plays an important role in the metabolism and growth and development of humans and animals. It exists in many foods such as dairy products, meat, fish, wheat, and oats. The normal value of L-Tyr content in the human body is 33-83 μmol / L. A higher content in the human body will have an impact on the liver, kidneys, etc., and a lower content may be symptoms of diseases such as hyperphenylalaninemia and vitiligo. Moreover, its content also affects the coat color and development of animals such as pigs and sheep. Therefore, it is very necessary to establish a method for accurately detecting the content of L-Tyr in biological fluids.

[0003] Prussian blue analogs (PBA) are a typical type of metal-organic framework material with a chemical general formula of A x M1[M2(CN)6] y ·H 1-y ·nH2O, where A refers to alkali metal ions such as Li, Na, K, etc.; and M1, M2 include transition metal ions such as Fe, Co, Ni, Mn, Zn, Cu, Mg, etc., H is a hole, 0 < x < 2, 0 < y < 1. The structure of PBA is similar to that of Prussian blue, with cyanide ligands alternately connecting coordinated Fe 2+ and Fe 3+ substituted by ions of transition metals such as Co, resulting in defects in the originally defect-free lattice structure, forming more active sites, combined with an open framework structure, making it show better electrochemical response, larger specific surface area, and better stability than Prussian blue.

[0004] Based on the oxidation reaction of L-Tyr on the electrode surface, electrochemical sensors have been widely used to detect this amino acid. However, on traditional electrodes, due to the low electroactivity of L-Tyr and high oxidation overpotential, the detection is insensitive. As a typical metal-organic framework material, PBA has good redox reversibility and a large number of active sites, which is very beneficial for modifying electrodes to improve electrocatalytic performance. Summary of the Invention

[0005] The purpose of the present invention is to provide an electrochemical sensing electrode based on a cobalt-iron-nitrogen-doped carbon nanocomposite of cubic CoFe-based Prussian blue to solve the problem of poor detection sensitivity of the current electrochemical sensors used to detect L-Tyr.

[0006] The electrochemical sensing electrode of the present invention is a cubic CoFe-type Prussian blue-based cobalt-iron-nitrogen-doped carbon nanocomposite material, characterized in that the electrochemical sensing electrode is composed of a GCE electrode and a cubic CoFe-type Prussian blue-based nitrogen-doped carbon nanocomposite material wrapped around the GCE electrode.

[0007] In the nitrogen-doped carbon nanocomposite material based on cubic CoFe-type Prussian blue, the CoFe-type Prussian blue is in the form of a cube, and the particle size of the cube is 500 nm.

[0008] The CoFe-based Prussian blue is synthesized by a hydrothermal method in a polytetrafluoroethylene reactor after Co-MOF and potassium ferrocyanide are dissolved in deionized water.

[0009] The amounts of Co-MOF cobalt nitrate hexahydrate, potassium ferrocyanide and 2-methylimidazole in the cobalt-iron-nitrogen-doped carbon nanocomposite material based on cubic CoFe-type Prussian blue are 1.5258 g, 1.3238 g and 0.5859 g, respectively.

[0010] The cobalt-iron-nitrogen-doped carbon nanocomposite material is prepared by calcining the CoFe-based Prussian blue in a tube furnace at 700°C. The obtained product is washed with deionized water and dried at 70°C.

[0011] The electrochemical sensing electrode based on cubic CoFe-like Prussian blue cobalt-iron-nitrogen-doped carbon nanocomposite material is obtained by mixing a sample with a Nafion® solution to prepare a suspension, which is then drop-coated on a GCE electrode and allowed to dry naturally.

[0012] Beneficial effects of the present invention:

[0013] Compared to traditional electrochemical sensors, the electrochemical sensing electrode constructed in this invention, based on a cubic CoFe-based Prussian blue and a cobalt-iron-nitrogen-doped carbon nanocomposite, overcomes the problems of limited detection range and poor sensitivity in practical L-Tyr detection. This is primarily due to the large number of active sites and high-speed ion channels in the cubic CoFe-based Prussian blue, which significantly enhance its electrocatalytic performance, thereby improving the sensor's detection range, sensitivity, and stability.

Claims

1. An electrochemical sensing electrode based on cubic CoFe-like Prussian blue cobalt-iron-nitrogen-doped carbon nanocomposite material, characterized in that The electrode is composed of GCE and a cubic cobalt-iron-nitrogen-doped carbon nanocomposite material wrapped around the GCE. In the cubic CoFe-like Prussian blue-based nitrogen-doped carbon nanocomposite material, the CoFe-like Prussian blue cubes have an average particle size of 500 nm, are separated from each other, and are evenly distributed. The electrochemical sensor electrode is used as a working electrode in an electrochemical sensor for detecting L-tyrosine. The preparation method of the electrochemical sensor electrode based on the cubic CoFe-like Prussian blue-based cobalt-iron-nitrogen-doped carbon nanocomposite material is completed by the following steps: (1) First, 1.5258 g of Co(NO3)2·6H2O and 0.5859 g of 2-methylimidazole were dissolved in 40 mL of deionized water. The purple precipitate obtained after standing overnight was centrifuged, washed with water and alcohol, and dried at 70 °C overnight to obtain Co-MOF. (2) 1.3238 g of potassium ferricyanide and Co-MOF were dissolved in 25 mL of deionized water, stirred for 10 min, placed in a 50 mL polytetrafluoroethylene-lined reactor, and reacted at 150 ° C for 18 h. The obtained product was washed alternately with deionized water and anhydrous ethanol three times and dried at 70 ° C overnight to obtain CoFe-based Prussian blue; (3) placing the CoFe-based Prussian blue in a porcelain boat, heating it to 700°C at a heating rate of 8°C / min in a nitrogen atmosphere, and annealing it for four hours to obtain a black powder, which was then washed with deionized water and dried at 70°C to obtain a cobalt-iron-nitrogen-doped carbon nanocomposite material; (4) Cobalt-iron-nitrogen doped carbon nanocomposites and The mixture of the solution (wt%=10%) was dropped onto the GCE electrode and naturally dried to obtain an electrochemical sensing electrode based on a cubic CoFe-like Prussian blue-doped cobalt-iron-nitrogen carbon nanocomposite material.