阅读说明：本技术 一种检测5-硝基愈创酚钠的电化学纳米酶传感器 (Electrochemical nano enzyme sensor for detecting 5-nitroguaiacol sodium ) 是由 段学民 卢欣宇 文阳平 徐景坤 周卫强 蔡悦 胥荃 于 2019-11-25 设计创作，主要内容包括：本发明公开了一种检测5-硝基愈创酚钠的电化学纳米酶传感器,属于电化学传感器技术领域,该传感器以饱和甘汞电极作为参比电极,铂片电极为对电极,复合电极为工作电极,组成三电极体系,采用醋酸盐缓冲溶液作为电解质溶液,利用差分脉冲伏安法检测待测溶液中5-硝基愈创酚钠的含量；所述复合电极为二硫化钼(MoS<Sub>2</Sub>)和羧基化多壁碳纳米管(COOH-MWCNT)修饰的复合电极。该传感器不仅能够成功检测5-硝基愈创酚钠,而且还具有灵敏度高、选择性强、稳定性好、具有酶的特性等特点。(The invention discloses an electrochemical nano enzyme sensor for detecting 5-nitroguaiacol sodium, which belongs to the technical field of electrochemical sensorsDetecting the content of the 5-nitroguaiacol sodium in the solution to be detected by an ampere method; the composite electrode is molybdenum disulfide (MoS) 2 ) And a carboxylated multi-walled carbon nanotube (COOH-MWCNT). The sensor not only can successfully detect the 5-nitroguaiacol sodium, but also has the characteristics of high sensitivity, strong selectivity, good stability, enzyme property and the like.)

1. DetectionThe electrochemical nanoenzyme sensor of the 5-nitroguaiacol sodium is characterized in that a three-electrode system is formed by taking a saturated calomel electrode as a reference electrode, a platinum sheet electrode as a counter electrode and a composite electrode as a working electrode, acetate buffer solution is taken as electrolyte solution, and the content of the 5-nitroguaiacol sodium in the solution to be detected is detected by using a differential pulse voltammetry method; the composite electrode is molybdenum disulfide (MoS)₂) And a carboxylated multi-walled carbon nanotube (COOH-MWCNT).

2. The electrochemical nanoenzyme sensor for detecting sodium 5-nitroguaiacol as claimed in claim 1, wherein the concentration of acetate buffer solution is 0.1M, pH is 4, and the voltage window is 0.5-1.0V.

3. The electrochemical nanoenzyme sensor for detecting sodium 5-nitroguaiacol as claimed in claim 1, wherein the composite electrode is prepared by the following steps:

(1) weighing single-layer molybdenum disulfide powder, preparing with deionized water, and performing ultrasonic treatment for 30min to obtain 1mg/mL molybdenum disulfide dispersion;

(2) weighing carboxylated multi-walled carbon nanotubes, preparing by using 0.5% perfluorosulfonic acid, and carrying out ultrasonic treatment for 30min to obtain 1mg/mL carboxylated multi-walled carbon nanotube dispersion liquid;

(3) mixing the obtained molybdenum disulfide dispersion liquid and the carboxylated multi-walled carbon nanotube dispersion liquid according to the volume ratio of 1: 1, and performing ultrasonic treatment for 1 hour to obtain the composite material MoS₂-COOH-MWCNT；

(4) Polishing glassy carbon electrode, dropping 10 μ L of the above composite material on the glassy carbon electrode, and drying at 60 deg.C to obtain composite electrode MoS₂-COOH-MWCNT。

Technical Field

The invention belongs to the technical field of electrochemical sensors, and particularly relates to an electrochemical nano enzyme sensor for detecting 5-nitroguaiacol sodium.

Background

The compound sodium nitrophenolate is a plant growth regulator, can promote wound healing and accelerate plant growth, and comprises the chemical components of 5-nitroguaiacol sodium (called 2-methoxy-5-nitrophenolate sodium), o-nitrophenolate sodium and p-nitrophenolate sodium, wherein the 5-nitroguaiacol sodium is the most key component of the compound sodium nitrophenolate, and has the best regulating capability, but the excessive use can cause the risk of teratogenesis. So far, the detection of the 5-nitroguaiacol sodium comprises a high performance liquid chromatography and electrochemical workstation combined technology, a high performance liquid chromatography-normal pressure chemical ionization-mass spectrometry combined technology and a high performance liquid chromatography, but the technologies are time-consuming, high in operation technology, expensive in equipment, complex in sample preparation and not suitable for wide application.

Enzymes play an important role in biocatalysts, but the activity of enzymes is easily destroyed under certain severe conditions, such as inappropriate pH or temperature. With the development of the technology, the nano enzyme becomes a bright point in the field of sensors, has the activity of the enzyme, meets the kinetic equation of the enzyme, and overcomes the severe requirements on catalytic conditions. In addition, nanoenzymes are easy to prepare and have strong durability. Recently, a new generation of materials such as carbon materials, metal nanoparticles, metal oxide nanoparticles, and the like have shown activity of nanoenzymes. These materials have been used for sensing (e.g., detection of ions, molecules, elimination of cells), therapeutic and environmental engineering.

The sensor has the advantages of time saving, high sensitivity, rapidness, simplicity, convenience and high efficiency, the sensor is widely applied to the detection of the aspects of optics, biology, clinic, food, pesticide and the like at present, the electrochemical detection research report on the 5-nitroguaiacol sodium is few at present, and the electrochemical behavior and the determination of the internal wile sensitivity and the like (wile sensitivity, Chenliji, 5-nitroguaiacol on the multiwalled carbon nanotube modified electrode [ J]The 'analysis and test journal' 2010) utilizes a multiwalled carbon nanotube modified electrode to carry out electrochemical detection on 5-nitroguaiacol sodium in a sodium citrate solution, and the linear range is 5 multiplied by 10^-5-5×10^-4mol L^-1The detection limit is 8.6 multiplied by 10^-7mol L^-1The linear range obtained by the method is narrow, and the sensitivity is low.

Disclosure of Invention

Aiming at the technical problems, the invention provides the electrochemical nano enzyme sensor for detecting the 5-nitroguaiacol sodium, which realizes the electrochemical detection of the 5-nitroguaiacol sodium and has the advantages of simpleness, high efficiency, low cost, rapidness and good selectivity.

In order to achieve the purpose, the invention adopts the following technical scheme:

an electrochemical nanoenzyme sensor for detecting 5-nitroguaiacol sodium comprises a three-electrode system, wherein a saturated calomel electrode is used as a reference electrode, a platinum sheet electrode is used as a counter electrode, a composite electrode is used as a working electrode, acetate buffer solution is used as electrolyte solution, and the content of the 5-nitroguaiacol sodium in a solution to be detected is detected by using a differential pulse voltammetry method; the composite electrode is molybdenum disulfide (MoS)₂) And a carboxylated multi-walled carbon nanotube (COOH-MWCNT).

Preferably, the acetate buffer solution has a concentration of 0.1M, a pH of 4, and a voltage window of 0.5-1.0V.

Preferably, the preparation method of the composite electrode is as follows:

(1) weighing single-layer molybdenum disulfide powder, preparing with deionized water, and performing ultrasonic treatment for 30min to obtain 1mg/mL molybdenum disulfide dispersion;

(2) weighing carboxylated multi-walled carbon nanotubes, preparing by using 0.5% perfluorosulfonic acid, and carrying out ultrasonic treatment for 30min to obtain 1mg/mL carboxylated multi-walled carbon nanotube dispersion liquid;

(3) mixing the obtained molybdenum disulfide dispersion liquid and the carboxylated multi-walled carbon nanotube dispersion liquid according to the volume ratio of 1: 1, and performing ultrasonic treatment for 1 hour to obtain the composite material MoS₂-COOH-MWCNT；

(4) Polishing glassy carbon electrode, dropping 10 μ L of the above composite material on the glassy carbon electrode, and drying at 60 deg.C to obtain composite electrode MoS₂-COOH-MWCNT。

The beneficial technical effects of the invention are as follows: the preparation method of the 5-nitroguaiacol sodium electrochemical nanoenzyme sensor established by the invention has the characteristics of low preparation cost, simple process and simple operation, can successfully detect the 5-nitroguaiacol sodium, has high sensitivity (the lower detection limit can reach 0.03 mu mol/L), strong selectivity, good stability, enzyme property and the like, and can be used for determining the content of the 5-nitroguaiacol sodium in chicken feed and tomatoes.

Drawings

FIG. 1 shows the MoS prepared₂-electron micrograph of COOH-MWCNT composite;

FIG. 2 shows the MoS prepared₂-differential pulsed voltammogram of COOH-MWCNT/GCE in 20 μmol/L5-nitroguaiacol sodium acetate buffer;

FIG. 3 is a differential pulse voltammogram of prepared composite electrodes in acetate buffer solutions of sodium 5-nitroguaiacol at different concentrations;

FIG. 4 is a graph of current versus concentration for prepared composite electrodes in acetate buffer solutions of sodium 5-nitroguaiacol at various concentrations;

FIG. 5 is a graph of the linear relationship between the reciprocal current and the reciprocal concentration of a prepared composite electrode in acetate buffer solutions of sodium 5-nitroguaiacol at different concentrations;

FIG. 6 is a graph of the stability of the electrochemical nanoenzyme sensor of sodium nitroguaiacol.

Detailed Description

The present invention will be further described with reference to the following specific examples.