CN107478707A - A kind of novel electrode and its assay method for blood sugar detection - Google Patents

Abstract

The present invention relates to the technical field of electrochemical analysis and detection, in particular to a new type of electrode that can be used for blood sugar measurement and its measurement method, comprising a glassy carbon electrode or a modified electrode as a working electrode, a saturated calomel electrode as a reference electrode, and a platinum wire as a A three-electrode system composed of auxiliary electrodes, the modified electrode is a carbon nanotube/palladium nanostructure composite material prepared by electrodeposition, the purpose of the present invention is to use the carbon nanotube/palladium nanocomposite modified electrode to establish a new method for measuring blood sugar The method is to study the electrochemical behavior of blood sugar on the modified electrode, and the method has higher selectivity and higher sensitivity to glucose, and is relatively easy to operate.

Description

A novel electrode for measuring blood sugar and its measuring method

technical field

The invention relates to the technical field of electrochemical analysis and detection, in particular to a novel electrode that can be used for blood sugar measurement and a measurement method thereof.

Background technique

Glucose is an important industrial raw material, mainly used in the food industry, such as the production of candy, cakes, beverages, etc. In the medical field, glucose is widely used in the infusion of patients. The oxidized product is gluconic acid, which is an important raw material for the production of calcium supplementation drug - calcium gluconate. It can be reduced to generate hexyl alcohol, which can be used to synthesize vitamin C. At present, people have done a lot of research on the detection of glucose, and developed a variety of glucose detection methods, mainly including chromatography, spectroscopy, biological methods and electrochemical methods. Compared with other methods, the stability and sensitivity of electrochemical detection of glucose have been greatly improved, so it has received great attention in the field of glucose detection and has achieved rapid development.

Contents of the invention

The purpose of the present invention is to modify the glassy carbon electrode with carbon nanotube/palladium nanostructure composite material, establish a new method for measuring blood sugar, study the electrochemical behavior of blood sugar on the modified electrode, and provide a new method for the measurement of blood sugar Analytical method.

In order to achieve the above object, the technical solution adopted in the present invention is: a three-electrode system consisting of a glassy carbon electrode or a modified electrode as a working electrode, a saturated calomel electrode as a reference electrode, and a platinum wire as an auxiliary electrode. The modified electrode is carbon nanotube/palladium nanostructure composite material. Place the three-electrode system in the processed serum, and record the cyclic volts of the peak current in the concentration range of 0.06-2.0 mg/mL under the condition of a sweep rate of 100 mV/s in the potential range of -0.8-0.4 V. An curve. The specific operation steps include:

1) Preparation of sensors: pretreatment of glassy carbon electrodes, purification and carboxylation of carbon nanotubes, preparation of carbon nanotube/palladium nanostructure composite electrode materials by electrodeposition;

2) Optimization of measurement conditions: the type of buffer solution, the influence of pH, the influence of deposition time, and the influence of scan rate;

3) Determination of actual samples: the working electrode is a glassy carbon electrode (GCE), the reference electrode is a saturated calomel electrode (SCE), and the counter electrode is a platinum wire electrode, forming a three-electrode system; the three-electrode system is placed in a well-processed The cyclic voltammetry curve of the peak current in the concentration range of 0.06-2.0 mg/mL was recorded under the optimal experimental conditions.

The invention utilizes the good electrical conductivity of the glassy carbon electrode and combines the properties of carbon nanotubes and palladium chloride to prepare an electrode with high sensitivity to glucose. Then, by optimizing parameters such as deposition time, buffer type, scanning rate, and bottom liquid pH, an electrochemical analysis method with high selectivity, high sensitivity, and easy operation for glucose was obtained, and this method was applied to Actual sample determination.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Accompanying drawing 1 is the sulfuric acid activation diagram of the bare electrode.

Accompanying drawing 2 is the cyclic voltammogram of different electrodes in potassium ferricyanide solution.

Accompanying drawing 3 is the cyclic voltammetry curve of different electrodes in 0.5mg/mL glucose solution.

Accompanying drawing 4 is the optimization curve of PH.

Accompanying drawing 5 is the optimization curve of deposition time.

Accompanying drawing 6 is the optimization curve of scan rate.

Accompanying drawing 7 is the CV figure of different concentration glucose solutions.

Accompanying drawing 8 is the reduction peak of the voltammetry characteristic analysis diagram of the glucose solution modified with carbon nanotubes/palladium chloride electrode with different concentrations, and the standard curve diagram made.

detailed description

A new electrode for measuring blood sugar and an electrochemical method using the electrode for measuring blood sugar involved in the present invention will be described in detail below with reference to the accompanying drawings.

In order to achieve the purpose of the invention, the technical solution adopted in the present invention is: a three-electrode system comprising a glassy carbon electrode or a modified electrode as a working electrode, a saturated calomel electrode as a reference electrode, and a platinum wire as an auxiliary electrode. The modified electrode is carbon nanotube/palladium nanostructure composite material.

Pretreatment of the glass electrode: Take the glassy carbon electrode and grind it on metallographic sandpaper (3000#), then polish it with 1.0, 0.3 and 0.05 μm Al ₂ O ₃ powder on the dry and wet suede pads respectively, and then use deionized Distilled water, absolute ethanol, and deionized distilled water were fully ultrasonically cleaned, and then the electrode was placed in 0.5mol/L H ₂ SO ₄ solution, at a scanning speed of 50mV/s, in the potential range of -0.5 to +1.4V, with a cyclic voltmeter An method (CV) scan 20 circles, take out the electrode activated by sulfuric acid, rinse it with distilled water, and place it in 0.01g/mL K ₃ [Fe(CN) ₆ solution, scan at 50mV/s at - In the 0.5-+1.2V potential range, use cyclic voltammetry (CV) to scan until it is stable.

Purification and carboxylation of carbon nanotubes: During the preparation of carbon nanotubes, amorphous carbon, carbon nanoparticles and carbon fibers are accompanied by the formation of amorphous carbon. In order to eliminate the influence of impurities as much as possible, carbon nanotubes Tubes need to be purified before carboxylation. Carbon nanotubes were heated at 400°C for 2 hours before use to remove the amorphous carbon on them. Carbon nanotubes were carboxylated by mixed acid reflux oxidation, that is, carbon nanotubes were mixed in V(HNO ₃ ):V(H ₂ SO ₄ ) =1:3 mixed solution, heated to reflux for 6h, filtered after cooling, centrifuged with ultrapure water until neutral, and dried in an oven. Prepare 0.5 mg/mL carbon nanotube dispersion liquid for use.

Preparation of carbon nanotube/palladium nanostructure composite electrode material by electrodeposition: Electrodeposition was prepared using CHI660 electrochemical workstation, using a three-electrode system: glassy carbon electrode (GCE) as the working electrode, platinum wire as the counter electrode, saturated calomel electrode ( SCE) as the reference electrode. A proper amount of carbon nanotube scattered liquid is dropped on the surface of the glassy carbon electrode, and dried under an infrared lamp to prepare the carbon nanotube modified electrode. This step is due to the strong conductivity of the carbon nanotubes, which makes the response signal of the modified electrode more obvious. The carbon nanotube modified electrode was placed in 0.5mmol/L palladium chloride solution, and was deposited at -0.2V for 180s at a constant potential to prepare a nano-palladium/carbon nanotube modified electrode.

Accompanying drawing 1 is the sulfuric acid activation diagram of the bare electrode. Take the glassy carbon electrode and polish it on metallographic sandpaper (3000#), and then polish it with 1.0, 0.3 and 0.05 μm Al ₂ O ₃ powder on the dry and wet suede pads respectively, and then use deionized distilled water, absolute ethanol, Fully ultrasonically clean with deionized distilled water, then place the electrode in 0.5mol/L H ₂ SO ₄ solution, scan with cyclic voltammetry (CV) at a scanning speed of 50mV/s, in the potential range of -0.5～+1.4V 20 laps. Take out the electrode activated by sulfuric acid, rinse it with distilled water, and place it in 0.01g/mL K ₃ [Fe(CN) ₆ ] solution, scan at a speed of 50mV/s, in the potential range of -0.5～+1.2V, Scan with cyclic voltammetry (CV) until stable.

Accompanying drawing 2 is the cyclic voltammogram of different electrodes in potassium ferricyanide solution. Use glassy carbon electrode, carbon nanotube modified electrode, carbon nanotube/palladium chloride modified electrode to scan by cyclic voltammetry in 5mmol/L K ₃ [Fe(CN) ₆ ] solution (potential range -0.4～0.8 V, scan speed 50mV/s). In the figure, the carbon nanotube modified electrode (curve c) increases the oxidation peak current and reduces the reduction peak current compared with the glassy carbon electrode (curve b), indicating that the carbon nanotubes have aggregated to the surface of the GCE, which promotes the redox of the probe ions on the electrode surface reaction. And when palladium chloride is modified on the surface of carbon nanotubes (curve a), the redox peak on the carbon nanotube/palladium chloride modified electrode is more prominent, and the peak current is further enhanced, indicating that palladium chloride significantly enhances the conductivity of the electrode. The property makes the electron flow rate on the electron surface significantly enhanced, thereby promoting the reversible reaction of the probe molecule K ₃ [Fe(CN) ₆ on the electrode surface.

Accompanying drawing 3 is the cyclic voltammetry curve of different electrodes in 0.5mg/mL glucose solution. Glucose solution with a concentration of 0.5mg/mL prepared with PBS buffer solution with pH=6.8, glassy carbon electrode, carbon nanotube modified electrode, palladium chloride modified electrode, carbon nanotube/palladium chloride modified electrode at -0.8～0.4 Under the condition of scanning speed of 100mV/s between V potential ranges, cyclic voltammetry scanning of different electrode scans, reversible oxidation peaks and reduction peaks appeared on carbon nanotube/palladium chloride modified electrodes and carbon nanotube modified electrodes, It shows that the electrode reaction process of glucose is reversible. At the same time, it can also be seen that the electrochemical catalytic effect of the carbon nanotube/palladium chloride modified electrode on glucose is significantly enhanced, indicating that the modified electrode has the largest response to glucose.

Accompanying drawing 4 is the optimization condition of PH. In this experiment, PBS buffer solution with pH=6.7 was used as the bottom solution for the determination of glucose content.

Accompanying drawing 5 is the optimization curve of deposition time. When the deposition time is 3min, the catalytic current will appear the maximum value.

Accompanying drawing 6 is the optimization curve of scanning speed. When the scanning speed is 100mV/s, the peak current is the largest.

Accompanying drawing 7 is the CV figure of different concentration glucose solutions. Use PBS buffer solution with pH=7 to prepare glucose solutions with concentration of 0.06mg/mL, 0.5mg/mL, 1.0mg/mL, 1.5mg/mL and 2.0mg/mL respectively. Glucose solutions with different concentrations were measured by modified electrode by voltammetry.

Accompanying drawing 8 is standard curve. Use carbon nanotubes/palladium chloride to modify the reduction peaks in the voltammetric characteristic analysis graphs of glucose solutions with different concentrations, and use Excel software to make a standard curve.

The invention utilizes the good electrical conductivity of the glassy carbon electrode and combines the properties of carbon nanotubes and palladium chloride to prepare an electrode with high sensitivity to glucose. Then, by optimizing parameters such as deposition time, buffer type, scanning rate, and bottom liquid pH, an electrochemical analysis method with higher selectivity, higher sensitivity, and easier operation for glucose was obtained.

Claims (3)

1. A kind of 1. novel electrode for blood sugar detection, it is characterised in that including：Glass-carbon electrode or modified electrode are work electricity Pole, saturated calomel electrode are reference electrode, platinum filament for auxiliary electrode group into three-electrode system.
2. 2. a kind of novel electrode for blood sugar detection as claimed in claim 1, it is characterised in that modified electrode is carbon nanometer Pipe/palladium nanostructure composite material.
3. 3. a kind of a kind of novel electrode for blood sugar detection using described in claim 1 determines the method for blood glucose, its feature It is, the three-electrode system is placed in the serum handled well, speed is swept with 100mV/s between -0.8~0.4V potential ranges Under the conditions of, record peak current is in the cyclic voltammetry curve that concentration is in the range of 0.06~2.0 mg/mL.