CN114957684A - TCPP (Ni) -Co electrode material and preparation method thereof - Google Patents

Abstract

The invention discloses a TCPP(Ni)-Co electrode material and a preparation method thereof. Through the synergistic use of microwave hydrothermal and ultrasonic methods, the product crystallization is completed at low temperature, and the synthesis yield of bimetallic TCPP(Ni)-Co with ultrathin two-dimensional structure features reaches 68%-75%. Using a step-by-step assembly strategy, metallic Ni ²⁺ and Co ²⁺ were immobilized on the nitrogen coordination center and carboxyl coordination center of 5, 10, 15, 20-tetracarboxyphenylporphyrin, respectively, to realize bimetallic in TCPP ( The co-coordination in Ni)‑Co provides two types of active sites for highly selective electrochemical detection of theophylline.

Description

A kind of TCPP(Ni)-Co electrode material and preparation method thereof

technical field

The invention relates to the field of electrochemical sensors, in particular to a TCPP(Ni)-Co electrode material and a preparation method thereof.

Background technique

Theophylline is a common dietary purine alkaloid found in a variety of beverages and natural ingredients. However, theophylline also has toxicological characteristics and may cause convulsions, tachycardia, and gastrointestinal problems when ingested inappropriately. Therefore, it is very important to detect theophylline with high sensitivity and strong anti-interference by electrochemical methods.

Electrochemical sensors are one of the most commonly used methods for detecting theophylline, in which electrode modification materials play a very critical role in the working process of electrochemical sensors. Two-dimensional layered metal-porphyrin framework materials (M-TCPPMOF) The extremely high specific surface area, two-dimensional layered structure, large porosity, and unsaturated metal sites have gradually been developed as high-performance electrode modification materials.

At present, the common problems of metal-porphyrin skeleton modified electrodes commonly used for theophylline detection are:

First, the anti-interference ability is not strong, which is due to the insufficient specific adsorption and recognition ability of a single type of active site in the electrode for theophylline, which leads to its limited practical application ability in the coexistence environment of various reducing substances. lack of specificity.

Second, because porphyrin has a planar macromolecular conjugated structure, its reactivity is low under conventional hydrothermal-solvothermal conditions, and the resulting ultra-thin two-dimensional layered structure has low precipitation efficiency during natural cooling. Therefore, the yield of two-dimensional metal-porphyrin framework materials is low. Generally, the yield of the mechanical exfoliation method is only about 15%. Although the intercalation chemical exfoliation method can reach 57%, the existing technology has the problem of low yield.

SUMMARY OF THE INVENTION

The invention provides a TCPP(Ni)-Co electrode material and a high-yield preparation method to solve the problems of insufficient specificity and low yield of metal-porphyrin skeleton ultrathin two-dimensional layered materials in the existing theophylline detection. .

In order to achieve the purpose of the present invention, the technical solution provided by the present invention is: a TCPP(Ni)-Co electrode material and a preparation method thereof, comprising the following steps:

Step 1: Weigh 0.3～0.5mmol of 5,10,15,20-tetracarboxyphenylporphyrin (H ₂ TCPP), put the weighed medicine into a 100mL quartz reaction flask, add 30～50mL N,N- Dimethylformamide, heated to 50°C with stirring, the drug was completely dissolved to form solution A;

Step 2: Weigh 3～5mmol NiSO ₄ ·6H ₂ O, dissolve in 6～10mL N,N-dimethylformamide to form solution B, then add solution B dropwise to solution A to form solution C;

Step 3: Place the solution C in the microwave ultrasonic reactor, in the temperature control mode, set the microwave reaction temperature to 80°C, the ultrasonic frequency of 26KHz to 28KHz, and the reaction time to be 40 to 60 minutes; after the reaction is over, set the reaction bottle to Cooling in a low temperature environment of -20°C for 2 hours to obtain TCPP(Ni) dark purple crystals with a yield of about 83-88%;

Step 4: Weigh 0.3-0.5 mmol CoSO ₄ ·7H ₂ O (0.1405 g) and 0.1-0.2 mmol TCPP(Ni), put the above medicines into a 50 mL quartz reaction flask, add 20-30 mL mixed solution (N, N-dimethylformamide: absolute ethanol volume ratio = 3:1), mix and stir for 30 minutes, after the drug is completely dissolved, obtain solution D, place solution D in the microwave ultrasonic reactor, and set the temperature control mode. The microwave reaction temperature is 150°C, the ultrasonic frequency is 26KHz to 28KHz, and the reaction time is 1 to 2 hours; after the reaction is completed, the reaction flask is placed in a low temperature environment of -20°C to cool down for 2 hours, washed with ethanol and centrifuged 3 times, and then dried. The TCPP(Ni)-Co dark purple product was obtained. The yield is about 68% to 75%.

Compared with the prior art, the advantages of the present invention are:

1. In the present invention, by using microwave hydrothermal and ultrasonic means, the product crystallization is completed by means of low temperature, and the metal Ni ²⁺ and Co ²⁺ are respectively fixed on 5, 10, 15, 20-tetracarboxyphenyl by using a step-by-step assembly strategy. The nitrogen coordination center and carboxyl coordination center of porphyrin realize the co-coordination of bimetals in TCPP(Ni)-Co, providing two types of active sites. Therefore, the anti-interference ability is effectively improved, and the specificity is significantly enhanced.

2. The preparation method provided by the present invention can increase the synthesis yield of the two-dimensional metal-porphyrin skeleton to 68%-75%, thereby improving the utilization efficiency of raw materials and the yield of products.

3. The preparation method of the present invention is simple, the raw materials are readily available, the microwave hydrothermal reaction time is short, and the energy consumption is low.

Description of drawings

Fig. 1 is the SEM image of the TCPP (Ni)-Co synthesized by the present invention;

Fig. 2 is the XRD pattern of the TCPP (Ni)-Co synthesized by the present invention;

Figure 3 is a graph of amperometric current response in the presence of various interfering substances.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

Example 1:

A high-yield preparation method for TCPP(Ni)-Co electrode material, comprising the following steps:

Step 1: Weigh 0.3mmol of 5,10,15,20-tetracarboxyphenylporphyrin (H ₂ TCPP) into a 100 mL quartz reaction flask, add 30 mL of N,N-dimethylformamide, stir and heat to 50 ℃, the drug is completely dissolved to form solution A;

Step 2: Weigh 3 mmol NiSO ₄ ·6H ₂ O, dissolve it in 6 mL N,N-dimethylformamide to form solution B, then add solution B dropwise to solution A to form solution C;

Step 3: Place solution C in a microwave ultrasonic reactor, set a microwave reaction temperature of 80°C, an ultrasonic frequency of 28KHz, and react for 60 minutes; after the reaction, place the reaction flask in a -20°C environment to cool down for 2 hours to obtain TCPP(Ni) dark purple crystals in about 88% yield.

Step 4: Weigh 0.3mmol CoSO ₄ ·7H ₂ O and 0.1mmol TCPP(Ni) into a 50mL quartz reaction flask, add 20mL mixed solution (N,N-dimethylformamide: absolute ethanol volume ratio= 3:1), mix and stir for 30min, after the drug is completely dissolved, obtain a suspension D, place the suspension D in a microwave ultrasonic reactor, set a microwave reaction temperature of 150 ° C, an ultrasonic frequency of 28KHz, and react for 2 hours; The reaction flask was cooled at -20°C for 2 hours, washed with ethanol and centrifuged three times, and dried to obtain a TCPP(Ni)-Co dark purple product with a yield of about 75%. Referring to Figure 1, it can be seen that the morphology of TCPP(Ni)-Co is a porous curd structure formed by the self-assembly of nanosheets. Referring to Figure 2, it can be seen that TCPP(Ni)-Co has good crystallinity.

Example 2:

A high-yield preparation method for TCPP(Ni)-Co electrode material, comprising the following steps:

Step 1: Weigh 0.5mmol of 5,10,15,20-tetracarboxyphenylporphyrin ( _H2TCPP ) into a 100mL quartz reaction flask, add 50mL of N,N-dimethylformamide, stir and heat to 50 ℃, the drug is completely dissolved to form solution A;

Step 2: Weigh 5mmol NiSO ₄ ·6H ₂ O, dissolve it in 10mL N,N-dimethylformamide to form solution B, then add solution B dropwise to solution A to form solution C;

Step 3: place solution C in the microwave ultrasonic reactor, set microwave reaction temperature 80 ℃, ultrasonic frequency 26KHz, react 40 minutes; After finishing, the reaction flask was placed in the environment of -20 ℃ and cooled for 2 hours to obtain TCPP ( Ni) dark purple crystals in about 83% yield.

Step 4: Weigh 0.5mmol CoSO ₄ ·7H ₂ O and 0.2mmol TCPP(Ni) into a 50mL quartz reaction flask, add 30mL mixed solution (N,N-dimethylformamide: absolute ethanol volume ratio= 3:1), mix and stir for 30min, after the drug is completely dissolved, obtain a suspension D, place the suspension D in a microwave ultrasonic reactor, set a microwave reaction temperature of 150 ° C, an ultrasonic frequency of 26KHz, and react for 1 hour; after the end The reaction flask was placed in a -20°C environment to cool down for 2 hours, washed with ethanol and centrifuged three times, and dried to obtain a TCPP(Ni)-Co dark purple product. The yield is about 68%.

Embodiment three:

A high-yield preparation method for TCPP(Ni)-Co electrode material, comprising the following steps:

Step 1: Weigh 0.4mmol of 5,10,15,20-tetracarboxyphenylporphyrin ( _H2TCPP ) into a 100mL quartz reaction flask, add 40mL of N,N-dimethylformamide, stir and heat to 50 ℃, the drug is completely dissolved to form solution A;

Step 2: Weigh 4 mmol NiSO ₄ ·6H ₂ O, dissolve it in 8 mL N,N-dimethylformamide to form solution B, then add solution B dropwise to solution A to form solution C;

Step 3: place solution C in microwave ultrasonic reactor, set microwave reaction temperature 80 ℃, ultrasonic frequency 27KHz, react 50 minutes; After finishing, the reaction flask was placed in the environment of -20 ℃ and cooled down for 2 hours to obtain TCPP ( Ni) dark purple crystals in about 85% yield.

Step 4: Weigh 0.4mmol CoSO ₄ ·7H ₂ O and 0.15mmol TCPP(Ni) into a 50mL quartz reaction flask, add 25mL mixed solution (N,N-dimethylformamide: absolute ethanol volume ratio= 3:1), mix and stir for 30min, after the drug is completely dissolved, obtain the suspension D, place the suspension D in the microwave ultrasonic reactor, set the microwave reaction temperature 150 ° C, the ultrasonic frequency 26KHz, and react for 1.5 hours; after the end The reaction flask was placed in a -20°C environment to cool down for 2 hours, washed with ethanol and centrifuged three times, and dried to obtain a TCPP(Ni)-Co dark purple product. The yield is about 72%.

The above-mentioned embodiment 1 is the best embodiment, and the electrochemical detection of the TCPP(Ni)-Co electrode prepared in the embodiment 1 for theophylline comprises the following steps:

Step 1: Grind 30 mg of TCPP(Ni)-Co finely with a pestle, put it into a sample tube, add 3 mL of deionized water, and ultrasonically disperse it uniformly, then add 2 mL of Nafion (5wt%) solution, and ultrasonically disperse for 30 min to obtain the obtained solution. Required modified electrode suspension E. Glassy carbon electrodes (GCE) were polished on the fur surface with alumina slurries with particle sizes of 0.3 μm and 0.05 μm, respectively, for 15 minutes to a bright mirror surface. The surface of the GCE electrode was then cleaned with doubly distilled water under ultrasonic conditions and dried with nitrogen. Use a micro-injector to draw 3 μL of modified electrode suspension E dropwise onto the surface of the glassy carbon electrode, and let it dry naturally at room temperature to obtain the desired TCPP(Ni)-Co@GCE electrode, which is finally stored in a refrigerator at 4°C Waiting for testing.

Step 2: Using TCPP(Ni)-Co@GCE as the working electrode, platinum wire electrode as the counter electrode, saturated calomel electrode as the reference electrode, 0.2mol/L, pH=4.5 Na ₂ HPO ₄ -C ₄ H ₂ O ₇ is the electrolyte solution. Before the test, the solution is filled with nitrogen to discharge the oxygen in the solution.

Step 3: Using TCPP(Ni)-Co@GCE as the working electrode, platinum wire electrode as the counter electrode, saturated calomel electrode as the reference electrode, and 0.2mol/L, pH=4.5 Na ₂ HPO ₄ -C ₄ H ₂ O ₇ is the electrolyte solution. Before the test, the solution is filled with nitrogen to discharge the oxygen in the solution. Add 0.125 mmol/L theophylline solution to the electrolyte with a micro-injector for 4 consecutive drops, 4 μL each time, and then add 10 times the concentration of interfering substances, including ascorbic acid, sucrose, glucose, sodium citrate, glycine and chlorine. After each dropwise addition, the ampere current response at 1.0V was recorded. Finally, the ampere current anti-interference response curve was obtained. See Figure 3, which shows that the TCPP(Ni)-Co electrode modification material has excellent performance on the above substances when detecting theophylline. anti-interference performance.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (4)

1. A preparation method of TCPP (Ni) -Co electrode material is characterized by comprising the following steps: the method comprises the following steps:

1) weighing 0.3-0.5 mmol of 5,10,15, 20-tetracarboxyphenyl porphyrin, adding 30-50 mLN, N-dimethylformamide, stirring and heating to 50 ℃, and dissolving the medicine completely to form a solution A;

2) weighing 3-5 mmol of NiSO ₄ ·6H ₂ Dissolving O in 6-10 mL of N, N-dimethylformamide to form a solution B, and then dropwise adding the solution B into the solution A to form a solution C;

3) placing the solution C in a microwave ultrasonic reactor for reaction, and after the reaction is finished, placing a reaction bottle in a low-temperature environment of-20 ℃ for cooling for 2 hours to obtain TCPP (Ni) dark purple crystals;

4): weighing 0.3-0.5 mmol of CoSO ₄ ·7H ₂ Placing O and 0.1-0.2 mmol TCPP (Ni) into a 50mL quartz reaction bottle, adding 20-30 mL of mixed solution, mixing and stirring for 30min, obtaining a suspension D after the medicine is completely dissolved, placing the suspension D into a microwave ultrasonic reaction instrument, setting the microwave reaction temperature at 150 ℃, the ultrasonic frequency at 26 KHz-28 KHz, and the reaction time at 1-2 hours; after the reaction is finished, the reaction bottle is placed in a low-temperature environment of minus 20 ℃ for cooling for 2 hours, washed and centrifuged for 3 times by ethanol, and dried to obtain a TCPP (Ni) -Co dark purple product.

2. The method for preparing TCPP (Ni) -Co electrode material according to claim 1, wherein: in the step 3), the ultrasonic reaction is to place the solution C in a microwave ultrasonic reactor, set the microwave reaction temperature to be 80-90 ℃, the ultrasonic frequency to be 26 KHz-28 KHz, and the reaction time to be 40-60 minutes.

3. The method for preparing a TCPP (Ni) -Co electrode material according to claim 1 or 2, wherein: the mixed solution in the step 4) is N, N-dimethylformamide and absolute ethyl alcohol, and the volume ratio of the N, N-dimethylformamide to the absolute ethyl alcohol is 3: 1.

4. The TCPP (Ni) -Co electrode material prepared by the preparation method according to claim 1.

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