Construction method and application of electrochemical sensor for detecting endogenous H 2 S
阅读说明：本技术 一种内源性h2s检测的电化学传感器的构建方法及其应用 (Construction method and application of electrochemical sensor for detecting endogenous H 2 S ) 是由 赵媛 柯伟 刘瀚 于 2019-09-12 设计创作，主要内容包括：本发明提供了一种内源性H_2S检测的电化学传感器的构建方法,属于电化学分析技术领域。本发明主要内容包括：制备rGO/Fe_3O_4/Cu_2O磁性纳米材料,并与H_2S反应生成具有空穴结构的硫铜化合物rGO/Fe_3O_4/Cu_2O-Cu_9S_8,利用rGO/Fe_3O_4/Cu_2O-Cu_9S_8电化学信号弱的特点,构建了以rGO/Fe_3O_4/Cu_2O和H_2S(NaHS)为体系的电化学传感器,该传感器具有检测限低、准确度高等优点,在内源性H_2S的检测方面具有很好的应用前景。(the invention provides a method for constructing an electrochemical sensor for endogenous H 2 S detection, which belongs to the technical field of electrochemical analysis and mainly comprises the steps of preparing a rGO/Fe 3 O 4 /Cu 2 O magnetic nano material, reacting the magnetic nano material with H 2 S to generate a sulfur copper compound rGO/Fe 3 O 4 /Cu 2 O-Cu 9 S 8 with a cavity structure, and constructing the electrochemical sensor taking rGO/Fe 3 O 4 /Cu 2 O and H 2 S (NaHS) as a system by utilizing the weak electrochemical signal characteristic of rGO/Fe 3 O 4 /Cu 2 O-Cu 9 S 8 .)
1. A construction method of an electrochemical sensor for detecting endogenous H 2 S is characterized by comprising the following steps:
(1) synthesizing magnetic reduced graphene oxide:
Adding reduced graphene oxide into ethylene glycol, mixing and dissolving, adding ferric acetylacetonate, carrying out ultrasonic treatment on the mixed solution for 30-40min, then adding 1.4-1.6g of amine acetate, stirring for 30-50min, transferring the mixed solution obtained by stirring into a reaction kettle, carrying out reaction at the temperature of 190-210 ℃ for 22-26h, cooling to room temperature after the reaction is finished, carrying out solid-liquid separation to obtain a solid phase, cleaning the solid phase with water and ethanol, dissolving and dispersing the obtained solid phase again with water, and fixing the volume to 2-4mg/mL to obtain a magnetic reduced graphene oxide solution, namely an rGO/Fe 3 O 4 solution;
(2) Synthesis of rGO/Fe 3 O 4/Cu 2 O solution:
adding the rGO/Fe 3 O 4 solution obtained in the step (1) into 0.01-0.012g/mL of copper nitrate solution, carrying out ultrasonic treatment for 30-40min, uniformly mixing, then adding 80-100 mu L of 0.035-0.04mol/L NaOH solution while stirring, continuously stirring for 30-50min, then adding 400-450mL of 85-90mol/L hydrazine hydrate solution and stirring for 40-50min, then carrying out solid-liquid separation to obtain a solid phase, washing and drying the solid phase with water, and finally dispersing in water again to obtain 2-3mg/mL of rGO/Fe 3 O 4/Cu 2 O solution;
(3) MGCE electrode pretreatment:
MGCE with the diameter of 4-10mm is sequentially polished on alumina powder with the particle size of 0.4-0.6mm and 0.025-0.03mm, then the polished electrode is cleaned by ethanol and water, the cyclic voltammetry curve of the bare electrode is measured, when the potential difference between an oxidation peak and a reduction peak is less than 90mV, the polishing is finished, then the polished electrode is cleaned by ethanol and water, and the cleaned electrode is dried by nitrogen or argon for standby;
(4) Construction of the electrochemical sensor:
adding a certain amount of rGO/Fe 3 O 4/Cu 2 O solution obtained in the step (2) into a series of NaHS with different concentrations and ammonia water with the concentration of 5-7 wt%, reacting for a certain time, adsorbing the reacted magnetic mixed nano material by using a magnet, removing supernatant liquid, separating the magnetic mixed nano material, re-dissolving and dispersing the magnetic mixed nano material in ultrapure water, then dropwise coating a certain amount of the obtained solution on the surface of the electrode obtained in the step (3), performing electrochemical scanning on the obtained electrode, recording signal change, and establishing a standard curve between an electrochemical signal and the NaHS concentration of the reacted magnetic mixed nano material.
2. the construction method according to claim 1, wherein the concentration of the ethylene glycol solution for reducing graphene oxide in step (1) is 1-2 w/v%, and the mass ratio of reduced graphene oxide, ferric acetylacetonate and amine acetate is 30-60:15-35: 100-.
3. The construction method according to claim 1, wherein the volume usage ratio of the reduced graphene oxide dispersion liquid, the copper nitrate solution, the NaOH solution and the hydrazine hydrate solution in step (2) is 0.2-1.2:5-15:0.04-0.16: 200-.
4. the method of claim 1, wherein the electrochemical scanning in step (3) is performed at a voltage ranging from-0.5 v to 0.3 v.
5. the construction method of claim 1, wherein the electrochemical sensor in step (4) is constructed by placing 5-12 parts of 20-30 μ L of the rGO/Fe 3 O 4/Cu 2 O dispersion obtained in step (2) into a centrifuge tube, adding 100-150 μ L of NaHS solutions with different concentrations, adding 20-30 μ L of 5-7 wt% ammonia water, reacting for 50-70min, separating the reacted magnetic mixed nano-materials, re-dispersing the separated magnetic mixed nano-materials into 20-30 μ L of ultrapure water, applying 8-12 μ L of the dispersed liquid onto the surface of the electrode obtained in step (3), performing electrochemical scanning, recording signal changes, and establishing a standard curve between the electrochemical signal and the NaHS concentration of the magnetic mixed nano-materials.
6. the method of claim 5, wherein the NaHS solution is used at a concentration ranging from 0.5 to 100000 nM.
7. The construction method according to claim 1 or 5, wherein the magnetic mixed nanomaterial is a mixture of rGO/Fe 3 O 4/Cu 2 O and rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 nanomaterials.
8. an electrochemical sensor for detecting endogenous H 2 S, which is prepared by the construction method of claim 1, and is applied to the detection of endogenous H 2 S.
Technical Field
The invention belongs to the technical field of electrochemical analysis, and particularly relates to a construction method of an electrochemical sensor for detecting endogenous H 2 S.
Background
H 2 S in organisms is mainly produced by three enzymes, cystathionine-beta-synthase (CBS), cystathionine-gamma-lyase (CSE) and fungi/yeast thioglycolic acid-sulfur transferase (3-MST), cystine (Cys). in normal biological systems, the presence of H 2 S contributes to the physiological activities of maintaining a healthy balance, but once the content of H 2 S in the organisms is unbalanced, the occurrence of certain diseases such as cervical cancer, colon cancer and certain lung diseases is marked, and therefore, a great number of researchers use H 2 S as a biological index to measure the healthy state, and thus, the detection of H 2 S is particularly important.
Compared with the detection methods, the electrochemical method has the characteristics of high sensitivity, easiness in operation, simplicity in instrument and the like, and brings great attention to people, for example, ferrocene and Ag NPs are used as electrochemical beacons, and the electrochemical signals are influenced by chemical reaction between sodium hydrosulfide and sodium sulfide as substitutes of H 2 S and the beacons so as to achieve the purpose of detecting H 2 S.
Meanwhile, in order to simplify the collection of materials and the modification process of electrodes, magnetic Fe 3 O 4 and a two-dimensional material rGO capable of improving electron conduction are reflected on sensor materials, and an rGO/Fe 3 O 4/Cu 2 O material is prepared.
disclosure of Invention
aiming at the defects of the prior art, the invention provides a construction method and application of an electrochemical sensor for detecting endogenous H 2 S.
the technical scheme of the invention is as follows:
A construction method of an electrochemical sensor for detecting endogenous H 2 S, comprising the following steps:
(1) synthesis of magnetic reduced graphene oxide (rGO/Fe 3 O 4):
adding reduced graphene oxide into ethylene glycol, mixing and dissolving, adding ferric acetylacetonate, carrying out ultrasonic treatment on the mixed solution for 30-40min, then adding 1.4-1.6g of amine acetate, stirring for 30-50min, transferring the mixed solution obtained by stirring into a reaction kettle, carrying out reaction at the temperature of 190-210 ℃ for 22-26h, cooling to room temperature after the reaction is finished, carrying out solid-liquid separation to obtain a solid phase, cleaning the solid phase with water and ethanol, dissolving and dispersing the obtained solid phase again with water, and fixing the volume to 2-4mg/mL to obtain a magnetic reduced graphene oxide solution, namely an rGO/Fe 3 O 4 solution;
(2) synthesis of rGO/Fe 3 O 4/Cu 2 O solution:
adding the rGO/Fe 3 O 4 solution obtained in the step (1) into 0.01-0.012g/mL of copper nitrate solution, carrying out ultrasonic treatment for 30-40min, uniformly mixing, then adding 80-100 mu L of 0.035-0.04mol/L NaOH solution while stirring, continuously stirring for 30-50min, then adding 400-450mL of 85-90mol/L hydrazine hydrate solution and stirring for 40-50min, then carrying out solid-liquid separation to obtain a solid phase, washing and drying the solid phase with water, and finally dispersing in water again to obtain 2-3mg/mL of rGO/Fe 3 O 4/Cu 2 O solution;
(3) MGCE electrode pretreatment:
MGCE with the diameter of 4-10mm is sequentially polished on alumina powder with the particle size of 0.4-0.6mm and 0.025-0.03mm, then the polished electrode is cleaned by ethanol and water, the cyclic voltammetry curve of the bare electrode is measured, when the potential difference between an oxidation peak and a reduction peak is less than 90mV, the polishing is finished, then the polished electrode is cleaned by ethanol and water, and the cleaned electrode is dried by nitrogen or argon for standby;
(4) construction of the electrochemical sensor:
and (3) adding a certain amount of the rGO/Fe 3 O 4/Cu 2 O dispersion liquid obtained in the step (2) into a series of NaHS with different concentrations and ammonia water with the concentration of 5-7 wt%, reacting for a certain time, adsorbing the reacted magnetic mixed nano material by using a magnet, removing supernatant liquid, separating the magnetic mixed nano material, redissolving and dispersing the magnetic mixed nano material in ultrapure water, then dropwise coating a certain amount of the obtained solution on the surface of the electrode obtained in the step (3), performing electrochemical scanning on the obtained electrode, recording signal change, and establishing a standard curve between the electrochemical signal and the NaHS concentration of the reacted magnetic mixed nano material.
The concentration of the ethylene glycol solution for reducing the graphene oxide in the step (1) is 1-2 w/v%, wherein the mass ratio of the reduced graphene oxide, the ferric acetylacetonate and the amine acetate is 30-60:15-35: 100-.
in the step (2), the volume usage ratio of the reduced graphene oxide dispersion liquid, the copper nitrate solution, the NaOH solution and the hydrazine hydrate solution is 0.2-1.2:5-15:0.04-0.16: 200-.
the voltage range of the electrochemical scanning in the step (3) is-0.5 v-0.3 v.
and (4) the construction of the electrochemical sensor in the step (4) comprises the following specific steps of parallelly taking 5-12 parts of 20-30 mu L of rGO/Fe 3 O 4/Cu 2 O dispersion liquid obtained in the step (2), respectively adding 100-150 mu L of NaHS solutions with different concentrations, simultaneously adding 20-30 mu L of ammonia water with the concentration of 5-7 wt%, reacting for 50-70min, respectively separating out the magnetic mixed nano material after reaction, taking out, respectively re-dispersing in 20-30 mu L of ultrapure water, then taking 8-12 mu L of the obtained dispersion liquid to drop and coat on the surface of the electrode obtained in the step (3), performing electrochemical scanning, recording signal change, and establishing a standard curve between the electrochemical signal and the NaHS concentration of the magnetic mixed nano material.
The concentration range of the NaHS solution is 0.5-100000 nM.
The magnetic mixed nano material is a mixture of rGO/Fe 3 O 4/Cu 2 O and rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 nano materials.
an electrochemical sensor for detecting endogenous H 2 S, which is applied to the detection of endogenous H 2 S.
the beneficial technical effects of the invention are as follows:
1. in the constructed electrochemical sensor, the used nano material has low cost and is simple and easy to obtain.
2. the principle of the invention is that an electroactive material rGO/Fe 3 O 4/Cu 2 O and NaHS are subjected to redox reaction to generate a sulfur copper compound rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 with a cavity structure, the electrochemical signal of the sulfur copper compound is weaker than that of rGO/Fe 3 O 4/Cu 2 O, the amount of rGO/Fe 3 O 4/Cu 2 O is reduced along with the increase of rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 in the reaction process, so that the electrochemical signal of the integral magnetic mixed nano material is weakened, and finally the purpose of detecting H 2 S is achieved by establishing a standard curve between the electrochemical signal of the integral magnetic mixed nano material and the concentration of NaHS, and the experimental principle is simple.
3. The existing method for detecting H 2 S is mainly a methylene blue method (the detection limit is about 8 mu M, and the detection range is 25 mu M-1000 mu M), and compared with the methylene blue method, the detection limit of the electrochemical sensor is 230pM, and the detection range is 500pM-500 mu M, so that the detection limit of the electrochemical sensor is lower, the detection range is wide, and the sensitivity is high.
4. According to the invention, by introducing Fe 3 O 4 and utilizing the magnetism of the material to be adsorbed on the surface of the magnetic electrode, the steps of electrode modification are greatly simplified, the cost of electrode modification is reduced, and errors caused by the traditional electrode modification process are reduced.
5. The reduced graphene oxide improves the electronic conduction capability of the sensor, so that the result is more accurate.
Drawings
FIG. 1 is the XRD patterns of the magnetic composite nano-materials of the intermediate product rGO/Fe 3 O 4/Cu 2 O, the final reaction mixture rGO/Fe 3 O 4/Cu 2 O and rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 prepared in example 1;
FIG. 2 is an XPS spectrum of the intermediate product rGO/Fe 3 O 4/Cu 2 O prepared in example 1, the final reaction mixture rGO/Fe 3 O 4/Cu 2 O and rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 magnetic composite nano-materials;
FIG. 3 is an AC impedance graph and a Cyclic Voltammetry (CV) graph of the electrochemical sensor prepared in example 1;
FIG. 4 is a DPV spectrum and validation UV spectrum of an electrochemical sensor;
FIG. 5 is a DPV graph of the electrochemical signals of reacted rGO/Fe 3 O 4/Cu 2 O and rGO/Fe 3 O 4/Cu 2 O-Cu 9 S 8 magnetic hybrid nanomaterials, as measured by the electrochemical sensor prepared in example 1, as a function of NaHS concentration, and a standard graph established between a peak current value and a NaHS concentration logarithm value.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings and examples.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：柔性电极及其制备方法、酶传感器及其制备方法