CN107478695A - Electrode based on the modification of nano-copper sulfide multi-walled carbon nanotube compound and its preparation method and application - Google Patents

Abstract

The invention discloses an electrode modified based on nanometer copper sulfide-multi-wall carbon nanotube composite, the surface of the electrode is covered with nanometer copper sulfide/multiwall carbon nanotube composite, and the electrode is a glassy carbon electrode. At the same time, the preparation method and application thereof are also provided. The nano-copper sulfide-multi-walled carbon nanotube composite modified electrode of the present invention has good electrocatalytic activity, and the modified electrode has low preparation cost, good reproducibility and stability, and high measurement sensitivity, and is especially suitable for the analysis of biologically active substances . The nano-copper sulfide multi-walled carbon nanotube composite of the present invention is used as a working electrode to form a three-level system as a sensor for the determination of paracetamol (PCT), which has high sensitivity.

Description

Electrode based on nano-copper sulfide-multi-walled carbon nanotube composite modification and its preparation Methods and Applications

technical field

The invention belongs to the field of electrochemical analysis, and in particular relates to an electrode modified based on nanometer copper sulfide-multi-walled carbon nanotube composite and its preparation method and application.

Background technique

Paracetamol (PCT), also known as acetaminophen or N-methyl-p-aminophenol, is one of the most widely used over-the-counter medicines in the world, which has the effect of reducing fever and relieving pain. However, excessive use can cause serious liver damage and other adverse consequences. Therefore, accurate determination of the content of paracetamol in medicines is helpful to control the safety of medicines and patients. At present, the commonly used analytical chemical methods for the determination of paracetamol (PCT) mainly include spectrophotometry, high performance liquid chromatography, capillary electrophoresis, chemiluminescence, electrochemical methods, and titration. Among them, the electrochemical analysis method has the characteristics of high sensitivity, fast analysis speed, simple instrument, easy operation and low cost, and has been widely used in the determination of biologically active molecules.

Electrochemical sensors developed based on electrochemical methods are a type of sensors that use electrodes as signal converters to measure potential or current. The electrochemical system realizes the input or output of electrical energy by means of electrodes, so as to obtain the electrical signal of the modified substance on the electrode surface, and a three-electrode system is commonly used. The three-electrode system includes a working electrode, an auxiliary electrode (also called a counter electrode) and a reference electrode, usually the counter electrode is a platinum electrode, the reference electrode is a saturated calomel electrode, and the working electrode is a glassy carbon electrode. However, the electrochemical analysis method is used to measure paracetamol (PCT), and there is a technical problem that the electrochemical response of paracetamol is poor on the bare electrode.

Nanomaterials refer to materials with an average particle size of less than 100nm. They have novel physical and chemical properties that many macroscopic objects do not possess. They are not only a dispersion system of multi-component substances, but also a new type of material. Nanomaterials have many special properties that solids do not have, such as volume effect, surface effect, quantum size effect, macroscopic quantum tunneling effect and dielectric confinement effect, etc., which make them have microwave absorption properties, high surface activity, strong oxidation, super Paramagnetism and absorption spectrum show obvious blue shift or red shift phenomenon, so it can be widely used. Such as: nano-copper sulfide (CuS), as a new type of wide-bandgap semiconductor photocatalytic material, has good biocompatibility and high electron transfer characteristics; carbon nanotubes (CNTs) are a single-layer or multi-layer The hollow tubular nano-carbon material formed by curling graphene sheets can be used as an electrode material to promote electron transfer of electroactive substances, accelerate electron exchange, and enhance electrochemical reactivity.

Contents of the invention

The purpose of the present invention is to provide an electrode based on nano-copper sulfide-multi-walled carbon nanotube composite modification, while providing its corresponding preparation method and application is another purpose of the present invention.

Based on the above-mentioned purpose, the present invention takes the following technical solutions:

The electrode is modified based on nanometer copper sulfide-multiwall carbon nanotube composite, the surface of the electrode is covered with nanometer copper sulfide/multiwall carbon nanotube composite, and the electrode is a glassy carbon electrode.

The preparation method of the electrode modified based on nano-copper sulfide-multi-walled carbon nanotube composite comprises the following steps: 1) dissolving 12-20 mg of polyvinylpyrrolidone in 15-25 mL of MWCNTs aqueous solution with a concentration of 0.08-1.5 mg mL ^-1 , and then add 0.02～0.03mmol CuCl ₂ , 0.056～0.094mmol Na ₂ S in turn, mix to obtain a suspension, seal the suspension, heat at 160～200°C for 20-26h, cool, centrifuge, wash, and store at 45～ Dry at 55°C for 10-14 hours to obtain nano-copper sulfide/multi-walled carbon nanotube composites;

2) Dissolve 1.2-2.0 mg of the nano-copper sulfide/multi-walled carbon nanotube composite in step 1) in 1.5 mL of distilled water and ultrasonically mix it, drop-coat it on the surface of the electrode, and dry it.

Step 2) After the electrode is ground, polished, cleaned and dried, the nano-copper sulfide/multi-wall carbon nanotube composite in step 1) is dissolved in water and ultrasonically mixed, and then drop-coated on its surface.

Based on the application of nano-copper sulfide-multi-walled carbon nanotube composite modified electrode, the modified electrode is used as a working electrode to form a three-level system with a counter electrode and a reference electrode for the determination of paracetamol.

The counter electrode is a platinum electrode, and the reference electrode is a saturated calomel electrode.

Compared with the prior art, the present invention has the following beneficial effects:

1. The nano-copper sulfide-multi-walled carbon nanotube composite modified electrode of the present invention has good electrocatalytic activity, and the modified electrode has low preparation cost, good reproducibility and stability, and high measurement sensitivity, and is especially suitable for biological activity Analysis of matter. The nano-copper sulfide-multi-wall carbon nanotube composite of the present invention is used as a working electrode to form a three-level system as a sensor to measure paracetamol (PCT), and the sensitivity is high.

2. The preparation method of the present invention is simple and low in cost.

Description of drawings

The cyclic voltammogram of Fig. 1 different electrodes in potassium ferricyanide solution;

Fig. 2 is the cyclic voltammogram of different electrodes measuring PCT;

Fig. 3 is the AC impedance diagram of different electrodes;

Figure 4 shows the potential window behavior on different electrodes;

Figure 5 is the chronocoulombic behavior on different electrodes;

Figure 6 is the cyclic voltammogram of PCT in CuS/MWCNTs/GCE at different scan rates;

Figure 7 is the cyclic voltammogram of PCT in CuS/MWCNTs/GCE at different pH values;

Figure 8 is a differential pulse voltammogram of PCT at different concentrations.

detailed description

Example 1

The electrode is modified based on nano copper sulfide-multi-wall carbon nanotube composite, the surface of the electrode (glassy carbon electrode) is covered with nano copper sulfide/multi-wall carbon nano tube composite.

The preparation method based on the electrode modified by nano-copper sulfide-multi-walled carbon nanotube composites comprises the following steps: 1) dissolving 16 mg of polyvinylpyrrolidone in 20 mL of MWCNTs aqueous solution with a concentration of 0.1 mg mL ^-1 , and then adding 0.025 Mmol CuCl ₂ , 0.075 mmol Na ₂ S, stirred slowly at room temperature for 30 minutes, mixed to obtain a suspension, sealed the suspension, heated at 180°C for 24 hours, cooled naturally, centrifuged at 12000rpm for 10 minutes, discarded the supernatant, and the lower layer After the precipitate was washed three times with distilled water, it was dried at 50°C for 12 hours to obtain the nano-copper sulfide/multi-walled carbon nanotube composite;

2) Grind the glassy carbon electrode (GCE) on sandpaper, and then polish it twice on the glass plate until the surface of the electrode is smooth (in the first polishing, the polishing powder on the glass plate is alumina powder with a particle size of 0.3 μm; During the second polishing, the polishing powder on the glass plate has a particle size of 0.05 μm aluminum oxide powder), then ultrasonic cleaning is carried out in absolute ethanol and distilled water successively, rinsed with twice distilled water, and dried for subsequent use;

3) Dissolve 1.5 mg of the nano-copper sulfide/multi-walled carbon nanotube composite in step 1) in 1.5 mL of double-distilled water and mix, and obtain a black suspension after ultrasonication for 2 hours, and then use a pipette to absorb 5 μL of the black suspension and drop it evenly Apply to the electrode surface and dry under infrared lamp.

Based on the application of nano-copper sulfide-multi-walled carbon nanotube composite modified electrodes, the dried glassy carbon electrode obtained in step 3) is used as a working electrode, and a platinum electrode is used as a counter electrode and a saturated calomel electrode is used as a reference. The electrodes constitute a three-level system for the determination of paracetamol.

Example 2

The preparation method of the electrode modified based on nano-copper sulfide-multi-walled carbon nanotube composites comprises the following steps: 1) dissolving 12 mg of polyvinylpyrrolidone in 15 mL of MWCNTs aqueous solution with a concentration of 1.5 mg mL ^-1 , and then adding 0.02 Mmol CuCl ₂ , 0.056 mmol Na ₂ S, stirred slowly at room temperature for 30 minutes, mixed to obtain a suspension, sealed the suspension, heated at 160°C for 26 hours, cooled naturally, centrifuged at 12000rpm for 10 minutes, discarded the supernatant, and the lower layer After the precipitate was washed three times with distilled water, it was dried at 45°C for 14 hours to obtain the nano-copper sulfide/multi-walled carbon nanotube composite;

2) Grind the glassy carbon electrode on sandpaper, and then polish it twice on the glass plate until the surface of the electrode is smooth (when polishing for the first time, the polishing powder on the glass plate is alumina powder with a particle size of 0.3 μm; the second time During polishing, the polishing powder on the glass plate has a particle size of 0.05 μm aluminum oxide powder), then ultrasonic cleaning is carried out in absolute ethanol and distilled water successively, and after being rinsed with twice distilled water, it is set aside;

3) Dissolve 1.2 mg of the nano-copper sulfide/multi-walled carbon nanotube composite in step 1) in 1.5 mL of double-distilled water and mix it. After ultrasonication for 2 hours, a black suspension is obtained, and 5 μL of the black suspension is evenly dripped with a pipette gun. Apply to the electrode surface and dry under infrared lamp.

Others are the same as embodiment 1.

Example 3

The preparation method based on the electrode modified by nano-copper sulfide-multi-walled carbon nanotube composites comprises the following steps: 1) 20mg polyvinylpyrrolidone is dissolved in 25mL concentration and is 0.08mg mL ^-1 in the MWCNTs aqueous solution, then add 0.03 mmol CuCl ₂ , 0.094 mmol Na ₂ S, stirred slowly at room temperature for 30 minutes, mixed to obtain a suspension, sealed the suspension, heated at 200°C for 20 hours, cooled naturally, centrifuged at 12000rpm for 10 minutes, discarded the supernatant, and the lower layer After the precipitate was washed three times with distilled water, it was dried at 55°C for 10 hours to obtain the nano-copper sulfide/multi-walled carbon nanotube composite;

2) Grind the glassy carbon electrode on sandpaper, and then polish it twice on the glass plate until the surface of the electrode is smooth (when polishing for the first time, the polishing powder on the glass plate is alumina powder with a particle size of 0.3 μm; the second time During polishing, the polishing powder on the glass plate has a particle size of 0.05 μm aluminum oxide powder), then ultrasonic cleaning is carried out in absolute ethanol and distilled water successively, and after being rinsed with twice distilled water, it is set aside;

3) Dissolve 2.0 mg of the nano-copper sulfide/multi-walled carbon nanotube composite in step 1) in 1.5 mL of twice-distilled water and mix, and obtain a black suspension after ultrasonication for 2 hours. Use a pipette to draw 5 μL of the black suspension and evenly drop it on Apply to the electrode surface and dry under infrared lamp.

Others are the same as embodiment 1.

Embodiment 4 Test example

Test method: The electrochemical behavior of the modified electrode in potassium ferricyanide solution and acetic acid-sodium acetate buffer solution (ABS) containing paracetamol (PCT) was studied by cyclic voltammetry (CV). Differential pulse voltammetry (DPV) was used to measure the effect of different concentrations of paracetamol (PCT) on the oxidation peak current. At the same time, the impedance, potential window, chronocoulomb, sweep rate, pH, etc. are also analyzed and determined. During the determination, paracetamol was diluted with a certain pH ABS buffer solution. The whole experiment process was carried out at room temperature.

Instruments and reagents: CHI660D electrochemical workstation (Shanghai Chenhua Instrument Co.); electronic balance (Shanghai Yueping Scientific Instrument Co., Ltd.); pHS-3C precision pH meter (Shanghai Dapu Instrument Factory); KQ2200E ultrasonic cleaner (Kunshan City Ultrasonic Instrument Co., Ltd.); XK96-B fast mixer (Jiangyan Xinkang Medical Instrument Co., Ltd.); MS-2000 magnetic stirrer (Henan Zhongliang Scientific Instrument Co., Ltd.); three-electrode system: nano-copper sulfide-carbon The nanotube composite nanomaterial modified glassy carbon electrode (d=3.0mm) was used as the working electrode, the saturated calomel electrode (SCE) was used as the reference electrode, and the platinum electrode was used as the counter electrode.

Paracetamol (PCT): analytically pure, Shanghai Pharmaceutical Company; MWCNTs: Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences; nano-copper sulfide nanomaterial (self-made); nano-copper sulfide/carbon nanotube composite material (self-made); potassium ferricyanide solution: Concentration 1mmol/LK ₃ [Fe(CN) ₆ ] solution, 1mmol/LK ₄ [Fe(CN) ₆ ] solution and 0.1mol/L KCl preparation; ABS buffer solution: mixed solution of 0.1mol/L acetic acid and sodium acetate The reagents used in the experiment were all analytically pure; the water used in the experiment was double distilled water.

4.1 Characterization of CV electrochemical behavior of different electrodes in potassium ferricyanide solution

Glassy carbon electrode (GCE), nano-copper sulfide modified electrode (CuS/GCE, the MWCNTs aqueous solution in its preparation method was replaced by distilled water, others are the same as in Example 1, the same below), carbon nanotube modified electrode (MWCNTs/GCE, its In the preparation method, no CuCl ₂ is added, the others are the same as in Example 1, the same below), the nano-copper sulfide-carbon nanotube composite nanomaterial modified electrode (CuS/MWCNTs/GCE) in Example 1 of the present invention is used as the working electrode, and the saturated Gan The mercury electrode (SCE) was used as the reference electrode, and the platinum electrode was used as the counter electrode to form a three-electrode system. Prepare the mixed aqueous solution of Fe(CN) ₆ ^3-/4- and KCl, the concentration of Fe(CN) ₆ ^3-/4- in the mixed aqueous solution is 1mmol/L (that is, Fe(CN) ₆ ^3- and Fe(CN ) ₆ ^4- the concentration is 1mmol/L), the concentration of KCl is 0.1mol/L (abbreviated as 1mmol/L Fe(CN) ₆ ^3-/4- +0.1mol/L KCl), at 1mmol/L Fe (CN) ₆ ^3-/4- +0.1mol/L KCl solution, with a scan rate of 100mv/s for cyclic voltammetry scanning, studied the electrochemical behavior of different electrodes, the results are shown in Figure 1. In Fig. 1 a: GCE; b: CuS/GCE; c: MWCNTs/GCE; d: CuS/MWCNTs/GCE, the following symbols are the same.

It can be seen from Figure 1 that the modified electrode prepared by the present invention has the largest measured peak current, and the peak shape is basically symmetrical. It can be seen that the modified electrode prepared by the present invention has good electrocatalytic activity and can significantly improve the analytical sensitivity.

4.2 Characterization of CV electrochemical behavior of PCT with different electrodes

Use 0.1mol/L ABS with pH=5.0 as a solvent to prepare a 0.5mmol/L PCT solution, and then use glassy carbon electrodes, nano-copper sulfide modified electrodes, carbon nanotube modified electrodes, and nano-sulfurized electrodes according to Example 1 of the present invention respectively. The copper-carbon nanotube composite nanomaterial modified electrode is used as the working electrode, the saturated calomel electrode is used as the reference electrode, and the platinum electrode is used as the counter electrode to form a three-electrode system. In the prepared PCT solution, the cyclic voltammetry scan was carried out at a scan rate of 100mV/s, and the electrochemical behavior of different electrodes was studied. The specific results are shown in Figure 2.

It can be seen from Fig. 2 that in the PCT solution, the peak current of the modified electrode of the present invention is also the largest, and the oxidation peak and the reduction peak present a good symmetry. It can be seen that due to the good electrical conductivity of nano-copper sulfide and carbon nanotubes, the sensitivity of the electrode measurement is significantly improved.

4.3 AC Impedance Study

In 1mmol/L Fe(CN) ₆ ^3-/4- +0.1mol/L KCl mixed solution, glassy carbon electrode, nano-copper sulfide modified electrode, carbon nanotube modified electrode, nano-copper sulfide of embodiment 1 of the present invention - The impedance of the carbon nanotube composite nanomaterial modified electrode was studied, and the results are shown in Figure 3.

It can be seen from Figure 3 that, compared with the bare electrode (glassy carbon electrode), the impedance on the nano-copper sulfide modified electrode is slightly reduced, while the impedance on the MWCNTs modified glassy carbon electrode (curve c) is significantly reduced, and the CuS-MWCNTs composite The impedance on the modified glassy carbon electrode (curve d) is also smaller than that on the bare electrode. It can be seen that the CuS-MWCNTs composite modified electrode of the present invention has low impedance and good conductivity, and can effectively promote the electron transfer rate on the electrode surface.

4.4 Potential window research

Use the ABS solution of 0.1mol/L pH=5.0, to the potential window of glassy carbon electrode, nano-copper sulfide modified electrode, carbon nanotube modified electrode, nano-copper sulfide-carbon nanotube composite nanomaterial modified electrode of embodiment 1 of the present invention The results of the analysis are shown in Figure 4.

It can be seen from Figure 4 that compared with the bare electrode (curve a), the potential window on the nano-copper sulfide modified electrode is slightly reduced (curve b), and the potential window on the MWCNTs modified electrode is also reduced (curve c). The potential window of -MWCNTs composite modified electrode is also reduced to a certain extent compared with the bare electrode, and the potential window range of CuS-MWCNTs composite modification is -1.5V～1.5V.

4.5 Chronocoulombic studies

Using 0.1mmol/L potassium ferricyanide solution, the chronocoulometry of the bare electrode and the CuS-MWCNTs/GCE electrode of Example 1 of the present invention was analyzed and studied, and the results are shown in FIG. 5 .

It can be seen from Fig. 5 that, compared with the bare electrode (curve a), the chronocoulombs on the CuS-MWCNTs composite modified glassy carbon electrode (curve d) are significantly reduced.

According to Anson's formula

Q＝2nFAcD ^1/2 t ^1/2 π ^1/2 +Qdc+Qds

where A is the working electrode surface area, c is the substrate concentration, Qdc is the electric double layer charge that can be eliminated, Qds is the Faradaic charge, and other symbols have the usual meanings.

Through experimental measurement and analysis, the Qt ^1/2 relationship curve of the bare electrode is:

Q(μC)＝-1.68t-0.027

Therefore, the electrode surface area of the bare electrode is calculated to be 0.01782 cm ² according to Anson's formula.

The Qt ^1/2 relationship curve of CuS-MWCNTs/GCE electrode is:

Q(μC)＝-9.46t-0.88

Therefore, the CuS-MWCNTs/GCE electrode surface area is calculated to be 0.10035cm ² according to Anson's formula.

It can be seen that the specific surface area of the CuS-MWCNTs/GCE electrode is 4 times larger than that of the bare electrode, which shows that the use of CuS-MWCNTs/GCE as an electrode material can accelerate electron transfer, enhance electrochemical reactivity, and improve reaction sensitivity.

4.6 Effect of different scan rates on the electrochemical behavior of PCT

With the ABS solution (the ABS solvent concentration is 0.1mol/L (pH 5.0)) containing the pH=5.0 of 0.5mmol/L PCT, will change the scanning speed in the range from 20mV/s to 600mV/s, use embodiment 1 of the present invention The CuS/MWCNTs/GCE used as the working electrode was scanned by cyclic voltammetry, and the results are shown in Figure 6. Scan rate (a-k): 20, 50, 80, 120, 150, 180, 200, 300, 400, 500, 600mV/s.

It can be seen from Figure 6 that when the scan rate changes from 20 to 600mV/s, both the oxidation peak current and the reduction peak current increase continuously with the increase of the scan rate. The square root of the oxidation peak current and the reduction peak current showed a good linear relationship with the scan rate. Among them, the linear equation of the oxidation peak current is: I(μA)=-2.3091v ^1/2 +0.4376, the linear correlation coefficient R=0.996, and the linear equation of the reduction peak current is: I(μA)=1.1711v ^1/2 + 0.8507, linear correlation coefficient R=0.997, indicating that the redox process of PCT on the electrode is controlled by diffusion. In order to reduce the background current and improve the signal-to-noise ratio, 100mV/s was selected as the scan rate in this experiment.

4.7 Effect of different pH buffer solutions on the electrochemical behavior of PCT

Using a series of ABS solutions with different pHs containing 0.5mmol/L PCT, using the CuS/MWCNTs/GCE modified electrode of Example 1 of the present invention as the working electrode, and using cyclic voltammetry for scanning research, the results are shown in Figure 7, a- f are respectively pH=3, 3.5, 4, 4.5, 5, 5.5.

It can be seen from Fig. 7 that the oxidation peak potential Ep and pH value of PCT satisfy the linear equation: Ep(V)=-0.0633pH+0.8025, and the linear correlation coefficient R=0.999. The slope of oxidation peak potential and pH is close to -56mV/pH, indicating that the number of electrons and protons are equal in the oxidation reaction of PCT. For the oxidation peak current, it can be observed that with the increase of pH, the current first increases and then decreases, and the oxidation peak current reaches the maximum at pH=5.0. Therefore, the ABS buffer solution with pH=5.0 can be regarded as the best supporting electrolyte.

4.8 Research on linear range and detection limit

A series of PCT solutions with different concentrations were prepared with a 0.1mol/L ABS buffer solution of pH=5.0, and the CuS/MWCNTs/GCE modified electrode of Example 1 of the present invention was used as a working electrode, and differential pulse voltammetry (DPV) was used to carry out electrical The research and analysis of chemical behavior, the results are shown in Figure 8, the PCT concentrations in the figure are: 2, 15, 30, 60, 100, 200 μmol/L.

It can be seen from Figure 8 that as the concentration of PCT solution increases, the oxidation peak current also gradually increases, and the oxidation peak current and concentration show a good linearity, and the linear equation is I(μA)=-0.16c(μmol/L) -0.04, the linear correlation coefficient is 0.998, and the detection limit is 2 μ mol/L.

In summary, the nano-copper sulfide-multi-walled carbon nanotube composite modified electrode of the present invention has good electrocatalytic activity, and the modified electrode has low preparation cost, good reproducibility and stability, and high measurement sensitivity, and is especially suitable for in the analysis of biological activity. The nano-copper sulfide-multi-wall carbon nanotube composite of the present invention is used as a working electrode to form a three-level system as a sensor to measure paracetamol (PCT), and the sensitivity is high.

Claims (5)

1. the electrode based on nano-copper sulfide-multi-walled carbon nanotube compound modification, it is characterised in that cover on the surface of the electrode It is stamped nano-copper sulfide/multi-walled carbon nanotube compound.

2. the preparation method of the electrode based on nano-copper sulfide-multi-walled carbon nanotube compound modification described in claim 1, its It is characterised by, comprises the following steps：1）It is 0.08 ~ 1.5 mg that 12 ~ 20mg polyvinylpyrrolidones are dissolved in into 15 ~ 25mL concentration mL^-1The MWCNTs aqueous solution in, then sequentially add 0.02 ~ 0.03mmol CuCl₂、0.056~0.094mmol Na₂S, mix Suspension is closed to obtain, suspension is sealed, 20-26h is heated at 160 ~ 200 DEG C, cooling, centrifugation, washing, is done at 45 ~ 55 DEG C Dry 10 ~ 14 h, produce nano-copper sulfide/multi-walled carbon nanotube compound；

2）Take 1.2 ~ 2.0mg steps 1）Nano-copper sulfide/multi-walled carbon nanotube compound to be dissolved in 1.5mL distilled water ultrasound mixed After conjunction, drop coating is in electrode surface, drying.

3. the preparation method of the electrode as claimed in claim 2 based on nano-copper sulfide-multi-walled carbon nanotube compound modification, Characterized in that, step 2）Electrode is after polishing, polish, clean, dry, then by step 1）Nano-copper sulfide/more walls carbon receive Mitron compound ultrasonic mixing soluble in water, then drop coating is in its surface.

4. the application of any described electrodes based on nano-copper sulfide-multi-walled carbon nanotube compound modification of claim 1-3, Characterized in that, using the electrode after modification as working electrode, with forming three electric grade systems to electrode and reference electrode, for surveying Determine paracetamol.

5. the application of the electrode as claimed in claim 4 based on nano-copper sulfide-multi-walled carbon nanotube compound modification, it is special Sign is that described is platinum electrode to electrode, and reference electrode is saturated calomel electrode.