CN111537461A - A method for detecting adenine and guanine in solution with boron cluster gold nanoparticles - Google Patents

Abstract

The invention is suitable for the identification and detection field of nano-gold, and provides a method for detecting adenine and guanine in a solution of boron cluster nano-gold. First, prepare the gold nanoparticles reduced by boron clusters according to the conventional process, and dilute it to obtain the diluted solution; then adjust the pH of the diluted solution with acid, and then add the sample aqueous solution to realize the specific recognition of adenine; There is no adenine in the system, then continue to add acid to adjust the pH of the solution, and then the specific recognition of guanine can be realized; finally, the obtained nano-gold sample solution is subjected to ultraviolet-visible absorption spectrum scanning, according to the nano-gold A ₆₅₀ /A ₅₂₅ . The signal strength can be used to measure the concentration of adenine or guanine. Compared with the traditional detection method, the invention has the advantages of convenience and quickness, low detection cost, less loss of raw materials, and low requirements for instruments.

Description

A method for detecting adenine and guanine in solution with boron cluster gold nanoparticles

technical field

The invention belongs to the field of identification and detection of nano-gold, in particular to a method for detecting adenine and guanine in a solution of boron cluster nano-gold.

Background technique

Purines are important contributors to human health and play a crucial role in supplying energy, forming coenzymes, and regulating metabolism. Adenine, formerly known as vitamin B ₄ , is an important part of DNA and RNA. It can promote the proliferation of white blood cells and is often used to treat leukopenia and acute neutropenia. In addition, it is also used to produce vitamins. B ₄ , plant growth hormone and other drugs, as well as biochemical research. Guanine is an organic base that exists widely in animals and plants, and is also an important base that constitutes nucleic acids. It is often used in the preparation of intermediates of antiviral drug acyclovir, preparation of caffeine and other drugs, and biochemical research.

The human body can rely on its own synthesis of adenine and guanine, and food also contains a lot of purine compounds. However, the more purines the body absorbs, the better. Purines are catabolized in the human body into uric acid, which is excreted in urine. If the human body takes in too much purine, purine metabolism disorder and uric acid excretion disorder will often occur, resulting in hyperuricemia, which is what we often call gout. Therefore, gout patients especially should control the intake of high purine, and the simple determination of purine content in the food and drugs they come into contact with is particularly important.

Nanogold colorimetry is a fast and convenient detection method based on phenomena that can be observed with the naked eye. When the gold nanoparticles are dispersed in the solution, the solution is wine red, and when the gold nanoparticles are agglomerated in the solution, the solution is blue-violet, which makes the nano-gold colorimetry can be easily applied to Qualitative analysis of samples. At the same time, this color change will also bring about the shift of the maximum absorption peak on the ultraviolet-visible absorption spectrum (from around 525nm to around 650nm), and the ratio of the absorbance of the sample around 650nm to around 525nm is within a certain range and the object to be tested in the sample. The concentration of gold nanoparticles is proportional to the concentration, which provides the basis for the quantitative analysis of samples by the nano-gold colorimetric method. However, the application of nanogold colorimetry often requires the connection of some recognition groups that can interact with the substance to be tested on the surface of gold nanoparticles, which usually leads to complex modification processes and loss of raw materials.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, the object of the present invention is to provide a kind of boron cluster nano-gold detection method for adenine and guanine in solution, aiming to solve the complicated operation, high detection cost, many loss of raw materials and requirements for instruments existing in the existing detection method Advanced technical issues.

The method includes the following steps:

Step S1: prepare the gold nanoparticles reduced by boron clusters according to a conventional process, and dilute it to obtain a diluted solution;

Step S2: adjusting the pH of the diluted solution with acid, and then adding the sample aqueous solution, the specific recognition of adenine can be realized;

Step S3: if there is no adenine in the system, continue to add acid to adjust the pH of the solution, so as to realize the specific recognition of guanine;

Step S4: Scanning the obtained nano-gold sample solution by ultraviolet-visible absorption spectrum, according to the signal strength of nano-gold A ₆₅₀ /A ₅₂₅ , the concentration of adenine or guanine can be determined.

Preferably, in step S1, Cs ₂ B ₁₂ H ₁₂ is used as reducing agent and stabilizer, Cs ₂ B ₁₂ H ₁₂ is added to the chloroauric acid solution in a molar ratio of 1:1, and stirred at 25° C. for 30 min , the gold nanoparticles reduced by boron clusters can be obtained.

Preferably, the concentrations of Cs ₂ B ₁₂ H ₁₂ and chloroauric acid in the solution are both 0.4 mM, and the solvent is water.

Preferably, in step S2, the pH of the solution is in the range of 2.0-2.5, and the concentration of the sample aqueous solution is 0-200 μM.

Preferably, in step S3, the pH of the solution is in the range of 1.8-2.0.

The invention provides a method for detecting adenine and guanine in a solution of boron cluster nano-gold, which has the following advantages:

1. Nano-gold synthesis adopts one-step method, the synthesis process is simple, and the loss of raw materials is small;

2. The preparatory work for the detection is simple, and the qualitative detection can be carried out after the solution is prepared;

3. The qualitative detection process is simple, the phenomenon is visible to the naked eye, and it is easy to observe;

4. Quantitative detection requires low instrument requirements, and can be completed by conventional UV-Vis spectrophotometer;

5. The detection of two kinds of purines can realize step-by-step detection, without complex pretreatment operation, only need to adjust the pH of the solution and record the discoloration time.

Description of drawings

Fig. 1 is the histogram of the UV-Vis absorption spectrum A ₆₅₀ /A ₅₂₅ pair base species under the condition of pH=2.0 for 0 min and 10 min in Example 1 of the present invention (base concentration is 200 μM);

Fig. 2 is the curve diagram of UV-Vis absorption spectrum A ₆₅₀ /A ₅₂₅ versus salt concentration at pH=2.0 for 0 h and 0.5 h in Example 2 of the present invention (base concentration is 40 μM);

3 is a graph of the UV-Vis absorption spectrum A ₆₅₀ /A ₅₂₅ at pH=2.0 for 0 h versus adenine concentration in Example 3 of the present invention (base concentration is 20 μM);

4 is a graph showing the UV-Vis absorption spectrum A ₆₅₀ /A ₅₂₅ for 1 h under the condition of pH=2.0 in Example 3 of the present invention versus guanine concentration (base concentration is 20 μM);

Fig. 5 is the UV-Vis absorption spectrogram of different base systems at 0 h under the condition of pH=2.0 in Example 4 of the present invention (base concentrations are all 20 μM);

FIG. 6 is the UV-Vis absorption spectra of different base systems under the condition of pH=2.0 for 1 h in Example 4 of the present invention (base concentrations are all 20 μM).

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.

A boron cluster nano-gold detection method for adenine and guanine in a solution, the method comprising the steps of:

Step S1: Prepare the gold nanoparticles reduced by boron clusters according to the conventional process, and dilute it to obtain a diluted solution.

In this step, when preparing gold nanoparticles reduced by boron clusters, Cs ₂ B ₁₂ H ₁₂ is used as reducing agent and stabilizer, and Cs ₂ B ₁₂ H ₁₂ is added to the chloroauric acid solution in a molar ratio of 1:1. , and stirred at 25 °C for 30 min to obtain gold nanoparticles reduced by boron clusters. The concentrations of Cs ₂ B ₁₂ H ₁₂ and chloroauric acid in the system are both 0.4 mM, and the solvent is water; when diluting the nano-gold, it should be diluted 2-10 times according to the type of the detection instrument, as a preferred , choose to dilute 4-5 times in this experiment.

Step S2: The pH of the diluted solution is adjusted with acid, and then the sample aqueous solution is added to realize the specific recognition of adenine.

In this step, the pH of the solution is in the range of 2.0-2.5, and only acid can be used to adjust the pH of the solution. Too high concentration of buffer solution will bring too high salt concentration, which will affect the stability of gold nanoparticles. The concentration of the sample aqueous solution is 0-200 μM.

Step S3: If there is no adenine in the system, continue to add acid to adjust the pH of the solution, so as to realize the specific recognition of guanine.

In this step, the pH of the solution is in the range of 1.8-2.0, and only acid can be used to adjust the pH of the solution.

In the detection of adenine and guanine, the pH value of the solution is not fixed, and the detection can be completed within a certain pH range, and the lower the pH value, the shorter the detection time, but the interference of other bases is also greater at this time. . For example, when pH = 2.0, adenine can be quickly detected, and the detection of guanine requires 10 minutes or even more than 1 hour according to the concentration of guanine; and when pH < 1.8, guanine can be detected quickly. However, after a period of time, cytosine, thymine, and uracil will also change the color of the solution successively.

Step S4: Scanning the obtained nano-gold sample solution by ultraviolet-visible absorption spectrum, according to the signal strength of nano-gold A ₆₅₀ /A ₅₂₅ , the concentration of adenine or guanine can be determined.

In this step, the obtained nano-gold sample solution is subjected to ultraviolet-visible absorption spectrum scanning, and within a certain range, the ratio of absorbance at 650 nm and 525 nm is proportional to the concentration of adenine or guanine.

In order to illustrate the technical solutions of the present invention, the following specific embodiments are used for description.

Example 1:

The Cs ₂ B ₁₂ H ₁₂ reduction-stabilized gold nanoparticles were diluted 4 times, and the pH of the solution was adjusted to 2.5, 2.0, and 1.8 with concentrated hydrochloric acid, and the volume of the concentrated hydrochloric acid used was recorded.

In addition, take the Cs ₂ B ₁₂ H ₁₂ reduction-stabilized gold nanoparticles and dilute it by 3 times, add concentrated hydrochloric acid in the same volume ratio of the previous step, and then add 1 volume of the original gold nanoparticles solution of adenine, guanine, cytosine, thymine, urine The aqueous solution of pyrimidine (the final concentration of base is 200 μM), the discoloration time of gold nanoparticles was recorded, and the results are shown in the following table.

The system was scanned by UV-Vis absorption spectrum, and the results are shown in Figure 1.

Embodiment 2:

Dilute the Cs ₂ B ₁₂ H ₁₂ reduction-stabilized gold nanoparticles by 2 times, add the same volume ratio of concentrated hydrochloric acid and different volumes of NaCl aqueous solution adjusted to pH 2.0 in Example 1, and use deionized water to dilute to a total solution volume of 3 times that of the original nano-gold solution. Finally, 1 volume of the original gold nanoparticles solution was added with deionized water or adenine aqueous solution and guanine aqueous solution. When the salt concentration was less than 70 mM, the system without purine did not change color obviously, while the system with adenine or guanine added color changed after different time. The system was scanned by UV-Vis absorption spectrum, and the results are shown in Figure 2.

Embodiment three:

Dilute the Cs ₂ B ₁₂ H ₁₂ reduction-stabilized gold nanoparticles by 3 times, add concentrated hydrochloric acid and NaCl aqueous solutions, and different volumes of adenine or guanine aqueous solutions, and make up with deionized water to dilute the gold nanoparticles in the final system by 4 times, the NaCl concentration was 70 mM, the pH of the system was 2.0, the adenine concentration was 0-10 μM, and the guanine concentration was 0-30 μM. At 0h and 1h, the system was scanned by UV-Vis absorption spectrum. Among them, at 0h, in the range of 0.01-1μM, the UV-Vis absorption spectrum A ₆₅₀ /A ₅₂₅ is proportional to the concentration of adenine; at 1h, in the range of 0.01-5μM, the UV-Vis absorption spectrum A ₆₅₀ /A ₅₂₅ is proportional to the concentration of adenine. The concentration of guanine is proportional. The results are shown in Figures 3 and 4.

Embodiment 4:

Dilute the Cs ₂ B ₁₂ H ₁₂ reduction-stabilized gold nanoparticles by 3 times, add concentrated hydrochloric acid and NaCl aqueous solution, and a certain volume of various base aqueous solutions, and dilute the volume with deionized water to dilute the gold nanoparticles in the final system by 4 times. , the NaCl concentration was 70 mM, the pH of the system was 2.0, and the concentrations of various bases were 20 μM. Among them, at 0h, the system with 4 kinds of bases without adenine is red, and the system with 5 kinds of bases is blue-violet; at 1h, the system with 3 kinds of bases without guanine is red, The system with the addition of 4 bases is blue-purple. The UV-Vis absorption spectrum of the system was scanned at 0h and 1h, and the results are shown in Figures 5 and 6.

In the embodiment of the present invention, the electrostatic interaction between the two permanent negative charges of the boron cluster and the protonated N of the purine under acidic conditions is used to make the gold nanoparticles agglomerate, thereby causing the color of the solution to change, so as to achieve a fast and convenient Identify the purpose of detection and quantification. At the same time, due to the inconsistent strength of the interaction between adenine, guanine and boron clusters, the discoloration time of gold nanoparticles under different acidic conditions is inconsistent, so that the two purines can be detected step by step. Compared with the traditional detection method, the present invention has the advantages of convenience and quickness, low detection cost, less loss of raw materials, and low requirements for instruments.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (5)

1. a method for adenine and guanine in boron cluster nano-gold detection solution, it is characterised in that the method comprises the steps: Step S1: prepare the gold nanoparticles reduced by boron clusters according to a conventional process, and dilute it to obtain a diluted solution; Step S2: adjusting the pH of the diluted solution with acid, and then adding the sample aqueous solution, the specific recognition of adenine can be realized; Step S3: if there is no adenine in the system, continue to add acid to adjust the pH of the solution, so as to realize the specific recognition of guanine; Step S4: Scanning the obtained nano-gold sample solution by ultraviolet-visible absorption spectrum, according to the signal strength of nano-gold A ₆₅₀ /A ₅₂₅ , the concentration of adenine or guanine can be determined. 2. the method for adenine and guanine in boron cluster nano-gold detection solution as claimed in claim 1, is characterized in that, in step S1, adopts Cs ₂ B ₁₂ H ₁₂ as reducing agent and stabilizing agent, according to mol ratio 1: Add Cs ₂ B ₁₂ H ₁₂ to the chloroauric acid solution in an amount of 1, and stir at 25° C. for 30 min to obtain the gold nanoparticles reduced by boron clusters. 3. the method for boron cluster nano-gold detection solution of adenine and guanine as claimed in claim 2, it is characterized in that, the concentration of Cs ₂ B ₁₂ H ₁₂ and chloroauric acid in the solution is 0.4mM, and the solvent is water. 4. The method for detecting adenine and guanine in a solution by boron cluster gold nanoparticles as claimed in claim 1, wherein in step S2, the pH of the solution is in the range of 2.0-2.5, and the concentration of the sample aqueous solution is 0-200 μM. 5 . The method for detecting adenine and guanine in a solution by boron cluster gold nanoparticles according to claim 1 , wherein, in step S3 , the pH of the solution ranges from 1.8 to 2.0. 6 .

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