A single-atom chemiluminescence enhancer and its preparation method and application

Abstract

The present invention relates to the field of chemiluminescence, and in particular to a single-atom chemiluminescence enhancer and its preparation method and application. The chemiluminescence enhancer includes a transition metal single-atom cobalt (Co) and a two-dimensional sheet nanomaterial C3N4; wherein the metal single-atom cobalt (Co) is dispersed in the two-dimensional sheet nanomaterial C3N4, and the metal single-atom cobalt (Co) is used as the central atom and C3N4 is used as a ligand to constitute a nano-metal single-atom dispersed material (Co-C3N4) as a chemiluminescence enhancer; the ratio of the C3N4 to the metal single-atom cobalt (Co) is 1g:0.0005-0.01mol. The chemiluminescence enhancer can improve the detection effect of biochemical molecules by enhancing the chemiluminescence intensity of the hydrogen peroxide-bisulfite system.

Description

Technical Field

[0001] The present invention relates to the field of chemiluminescence, in particular to a single-atom chemiluminescence enhancer, a preparation method thereof, and application thereof in a hydrogen peroxide (H2O2)-bisulfite (NaHSO3) system. Background Art

[0002] Chemiluminescence (CL) is a luminescent phenomenon caused by a chemical reaction. Analytical methods based on CL have the following advantages: high sensitivity, fast reaction speed, convenient operation, low instrument cost, and low background signal.

[0003] Currently, chemiluminescence analysis is widely used in a variety of fields, including environmental science, life science, food science, and clinical medical diagnosis. However, chemiluminescence analysis still suffers from issues such as weak luminescence signals and short luminescence duration. Therefore, finding suitable chemiluminescence enhancers to achieve higher chemiluminescence signals has become a research priority in the field of chemiluminescence. Researchers have tried various methods to achieve stronger chemiluminescence signals and thus improve detection sensitivity.

[0004] Single-atom metal dispersions (SACs) consist of a uniform dispersion of a single metal atom on a two-dimensional network support material (such as graphene or C3N4). These materials have been applied to numerous catalytic reactions due to their fully exposed active sites, refined electronic structure, unsaturated coordination environment, and strong metal-support interactions. Despite their outstanding performance in catalysis, their application in bioanalysis and sensing is still in its infancy. Therefore, designing SACs and applying them to biosensing holds great promise. Summary of the Invention

[0005] In view of the above problems, the embodiments of this specification provide a single-atom chemiluminescence enhancer and its preparation method and application, which can improve the detection effect of biochemical molecules by enhancing the chemiluminescence of the hydrogen peroxide-bisulfite system.

[0006] In the first aspect, the embodiments of the present invention provide a single-atom chemiluminescence enhancer, which includes a transition metal single-atom cobalt (Co) and a two-dimensional sheet nanomaterial C3N4; wherein the metal single-atom cobalt (Co) is dispersed in the two-dimensional sheet nanomaterial C3N4, and the metal single-atom cobalt (Co) is used as the central atom and C3N4 is used as a ligand to constitute a nano-metal single-atom dispersed material (Co-C3N4) serving as a chemiluminescence enhancer; the ratio of C3N4 to the metal single-atom cobalt (Co) is 1g:0.0005-0.01mol.

[0007] In one possible embodiment, the chemiluminescence enhancer is a nano-metal single-atom dispersed material (Co-C3N4) synthesized by ultrasonic method using cobalt chloride hexahydrate (CoCl2·6H2O) and two-dimensional sheet nanomaterial C3N4 as raw materials; wherein, in the nano-metal single-atom dispersed material (Co-C3N4), the ratio of C3N4 to metal single-atom cobalt (Co) is 1g:0.0005-0.001mol, and the two-dimensional sheet nanomaterial C3N4 is synthesized from melamine.

[0008] The chemiluminescence enhancer is a SAC nanomaterial, Co-C3N4, which is based on C3N4 and contains cobalt metal atoms (Co) as dispersed atoms, with a metal atom content of 0.004%.

[0009] In a second aspect, the present invention provides a method for preparing a single-atom chemiluminescence enhancer, comprising the following steps:

[0010] Melamine (C3H6N6) was placed in a muffle furnace, and the temperature of the muffle furnace was increased to 550°C at a heating rate of 5°C / min. Melamine (C3H6N6) was calcined for 2 hours to obtain a calcined product. Subsequently, 1 mol / L nitric acid was added to the calcined product and ultrasonically treated for 1 hour. The product was stirred for 24 hours to obtain a reaction solution. The reaction solution was filtered and washed, and then dried in an oven at 80°C for 12 hours to obtain C3N4 nanosheets.

[0011] The C3N4 nanosheets and cobalt chloride hexahydrate (CoCl2·6H2O) were then dissolved in 40 mL of ethanol, pre-stirred for 6 hours, and then ultrasonically treated for 1 hour. The product was stirred for 24 hours, filtered, washed, and placed in an oven at 110°C for 24 hours to obtain Co-C3N4; wherein the feed ratio of the C3N4 to cobalt chloride hexahydrate (CoCl2·6H2O) was 1 g:0.0005-0.01 mol.

[0012] In one possible embodiment, the feed ratio of C3N4 to cobalt chloride hexahydrate (CoCl2·6H2O) is 1g:0.0005-0.001mol.

[0013] In one possible embodiment, the feed ratio of C3N4 to cobalt chloride hexahydrate (CoCl2·6H2O) is 1 g:0.001 mol.

[0014] In one possible embodiment, the method includes the following steps:

[0015] 4 g of melamine (C3H6N6) was placed in a crucible and then placed in a muffle furnace. The muffle furnace was heated at a rate of 5°C / min, and the melamine (C3H6N6) was calcined at 550°C for 2 hours to obtain a calcined product; the calcined product was ground in a mortar, and then added with 1 mol / L nitric acid and ultrasonically treated for 1 hour; the calcined product was then placed in a reaction bottle and stirred for 24 hours to mix uniformly to obtain a first reaction solution; the first reaction solution was then placed in a suction filter and filtered three times with 500 mL of water; the filter paper containing the filtered product was placed in a petri dish and then dried in an oven at 80°C for 12 hours to obtain C3N4 nanosheets;

[0016] Add 40 mL of ethanol, 1 g of C3N4, and 0.001 mol of CoCl2·6H2O into the reaction flask, mix well, and stir for 6 h to obtain a uniform solution.

[0017] The reaction bottle was reacted under ultrasound for 1 hour, the frequency of ultrasonic treatment was 80 kHz, and the room temperature was maintained constant; after the ultrasonic reaction was completed, stirring was continued for 24 hours to make the product more uniform to obtain a second reaction solution; then the second reaction solution was placed in a suction filter and filtered three times with 500 mL of water; the filter paper containing the filtered product was placed in a culture dish and then placed in an oven and dried at 110° C. for 24 hours to obtain a chemiluminescence enhancer.

[0018] In a third aspect, the embodiments of the present invention provide the use of the above-mentioned single-atom chemiluminescence enhancer in a chemiluminescence system.

[0019] In one possible embodiment, the chemiluminescence system is a hydrogen peroxide (H2O2)-bisulfite (NaHSO3) system, and the chemiluminescence enhancing reagent is used to enhance the chemiluminescence intensity of the hydrogen peroxide (H2O2)-bisulfite (NaHSO3) system.

[0020] In one possible embodiment, the chemiluminescence enhancer is used to enhance the luminescence of the H2O2-NaHSO3 system, comprising the following steps: preparing a 0.02 mol / L NaHSO3 solution, adding the chemiluminescence enhancer to obtain a mixed solution; adding an H2O2 solution to the mixed solution so that the concentration of H2O2 in the mixed solution is 0.1 mol / L and each 2 mL of the mixed solution contains 0.5 mg of the chemiluminescence enhancer.

[0021] In a fourth aspect, the use of the single-atom chemiluminescence enhancer as described in the first aspect in detecting glutathione is provided, wherein the use is the use of the chemiluminescence enhancer in combination with H2O2 and NaHSO3 in detecting glutathione; wherein the chemiluminescence enhancing reagent is used to enhance the chemiluminescence intensity of the H2O2-NaHSO3 system, and the detection limit is 7.221 μM.

[0022] The single-atom chemiluminescence enhancer provided by the present invention can increase the chemiluminescence intensity of hydrogen peroxide-bisulfite systems, thereby improving detection sensitivity and accuracy, and further enhancing the detection effect of hydrogen peroxide-bisulfite chemiluminescence analysis methods. This single-atom chemiluminescence enhancer can be applied to bioanalysis and sensing to improve detection results, for example, improving the detection effect of chemiluminescence enhancers in glutathione detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 A scanning electron microscope (SEM) photograph of the single-atom dispersion material Co-C3N4 provided in the examples of the present application;

[0025] Figure 2 This is a transmission electron microscope (TEM) photograph of the single-atom dispersion material Co-C3N4 provided in the examples of the present application;

[0026] Figure 3 A high-angle annular dark field scanning transmission (HAADF-STEM) photograph of the single-atom dispersed material Co-C3N4 provided in an embodiment of the present application;

[0027] Figure 4 Energy dispersive spectrometer (EDS) photo of the single-atom dispersed material Co-C3N4 provided in the embodiment of this application

[0028] Figure 5 X-ray diffraction (XRD) spectrum of the single-atom dispersed material Co-C3N4 provided in the embodiments of the present application;

[0029] Figure 6 The infrared spectrum of the single-atom dispersed material Co-C3N4 provided in the embodiments of the present application;

[0030] Figure 7 This is the (X-ray photoelectron spectroscopy) XPS spectrum of the single-atom dispersed material Co-C3N4 provided in the examples of the present application;

[0031] Figure 8 Fluorescence spectrum of the single-atom dispersed material Co-C3N4 provided in the examples of this application;

[0032] Figure 9The chemiluminescence intensity of the NaHSO3-H2O2 system catalyzed by the single-atom dispersed material Co-C3N4 provided in the examples of this application;

[0033] Figure 10 is the chemiluminescence intensity of the NaHSO3-H2O2 system catalyzed by different metal doping;

[0034] Figure 11 is the chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system under different reaction ultrasound times;

[0035] Figure 12 is the chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system under different Co doping amounts;

[0036] Figure 13 The chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system under different sample addition orders;

[0037] Figure 14 is the chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system at different NaHSO3 concentrations;

[0038] Figure 15 is the chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system under different H2O2 concentrations;

[0039] Figure 16 is the chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system at different Co-C3N4 concentrations;

[0040] Figure 17 This is the (electron paramagnetic resonance) EPR spectrum of the Co-C3N4-NaHSO3-H2O2 system;

[0041] Figure 18 This is the dissolved oxygen experiment of Co-C3N4-NaHSO3-H2O2 system;

[0042] Figure 19 This is the chemical luminescence spectrum of the Co-C3N4-NaHSO3-H2O2 system;

[0043] Figure 20 Schematic diagram of the chemiluminescence mechanism of the Co-C3N4-NaHSO3-H2O2 system;

[0044] Figure 21 Schematic diagram of detecting glutathione concentration for Co-C3N4; DETAILED DESCRIPTION

[0045] It should be understood that the scope of protection of the present application is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present application are for the purpose of describing specific embodiments rather than for the purpose of limiting the scope of protection of the present application; in the specification and claims of the present application, unless otherwise expressly stated herein, the singular forms "a", "an" and "the" include plural forms.

[0046] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified herein, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of this application, any method, equipment, and material of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present application can also be used to realize this application.

[0047] The "room temperature" mentioned in the examples of this application has a meaning well known in the art, generally referring to 24-28°C.

[0048] Example 1

[0049] After a large number of experiments, the inventors of the present application found that SAC materials with transition metal cobalt as the central atom and C3N4 as the carrier can effectively promote the production of reactive oxygen species in the NaHSO3-H2O2 system, thereby enhancing the chemiluminescence performance of the NaHSO3-H2O2 system.

[0050] Based on the above findings, this application further selected transition metal Co as the central atom and C3N4 as the carrier, and prepared Co-C3N4 by ultrasonic method.

[0051] Therefore, the present invention uses the SAC material Co-C3N4 prepared by ultrasonic method with C3N4 as the carrier and transition metal cobalt as the central atom as the single-atom chemiluminescence enhancer, which can effectively improve the chemiluminescence intensity, especially suitable for hydrogen peroxide-bisulfite system.

[0052] The above is an introduction to the single-atom chemiluminescence enhancer provided by this solution. Next, the preparation method of the single-atom chemiluminescence enhancer described above will be introduced.

[0053] Example 2

[0054] The present invention provides a method for preparing the above-mentioned SAC material Co-C3N4. Specifically, the method uses C3N4 as a carrier and Co atoms as metal center atoms, and is prepared by ultrasonic method, including the following steps:

[0055] Step (1), placing melamine (C3H6N6) in a muffle furnace, heating the muffle furnace to 550°C at a heating rate of 5°C / min, and calcining the melamine (C3H6N6) for 2 hours to obtain a calcined product, then adding 1 mol / L nitric acid to the calcined product and ultrasonically treating it for 1 hour, and then stirring it for 24 hours to obtain a reaction solution, filtering and washing the reaction solution, and drying it in an oven at 80°C for 12 hours to obtain C3N4 nanosheets;

[0056] In step (2), the C3N4 nanosheets and cobalt chloride hexahydrate (CoCl2·6H2O) were dissolved in 40 mL of ethanol, pre-stirred for 6 h, and then ultrasonically treated for 1 h. The product was stirred for 24 h, filtered, washed, and dried in an oven at 110°C for 24 h to obtain Co-C3N4.

[0057] In a preferred embodiment, the mass of the reactants, reaction time, and filtration conditions are as follows:

[0058] 4 g of melamine (C3H6N6) was placed in a crucible and then placed in a muffle furnace. The muffle furnace was heated at a temperature of 5°C / min, and the melamine (C3H6N6) was calcined at 550°C for 2 hours to obtain a calcined product; the calcined product was ground with a mortar, and 1 mol / L nitric acid was added and ultrasonically treated for 1 hour (for example, the ultrasonic power was 300W and the ultrasonic treatment frequency was 80kHz); then the product was placed in a reaction bottle and stirred for 24 hours to mix it evenly to obtain a first reaction solution; then the first reaction solution was placed in a filter and filtered three times with 500 mL of water; the filter paper containing the filtered product was placed in a culture dish and then placed in an oven and dried at 80°C for 12 hours to obtain C3N4 nanosheets.

[0059] Add 40 mL of ethanol, 1 g of C3N4, and 0.001 mol of CoCl2·6H2O into the reaction flask, mix well, and stir for 6 h to obtain a uniform solution.

[0060] The reaction bottle was reacted under ultrasound for 1 hour, the frequency of ultrasonic treatment was 80 kHz, and the room temperature was maintained constant; after the ultrasonic reaction was completed, stirring was continued for 24 hours to make the product more uniform to obtain a second reaction solution; then the second reaction solution was placed in a suction filter and filtered three times with 500 mL of water; the filter paper containing the filtered product was placed in a culture dish and then placed in an oven and dried at 110°C for 24 hours to obtain the single-atom chemiluminescence enhancer described above.

[0061] Next, specific examples are used to illustrate the characteristics of the SAC material Co-C3N4 provided in this specification and the application of the SAC material Co-C3N4 in chemiluminescence.

[0062] Example 3

[0063] Figure 1 The scanning electron microscope (SEM) image of Co-C3N4 prepared according to the above method is shown in Figure 2. Figure 2 The transmission electron microscope (TEM) image of Co-C3N4 prepared according to the above method is shown in Figure 1. Figure 3 This is the high-angle annular dark field scanning transmission (HAADF-STEM) of Co-C3N4 prepared according to the above method. Figure 4 The energy dispersive spectrometer (EDS) of Co-C3N4 prepared according to the above method is shown in FIG. Figure 4 Figures a, b, c, and d correspond to the distribution of all elements, C, N, and Co, respectively. The SEM, TEM, and HAADF-STEM images reveal the Co-C3N4 nanosheet structure and the dispersion of metal atoms obtained using the aforementioned steps.

[0064] Figure 5 Figure 3 is the X-ray diffraction (XRD) pattern of Co-C3N4 prepared according to the above method. Compared with the raw materials C3N4 and CoCl2·6H2O, it can be seen that the Co-C3N4 prepared according to the above steps has the structure of C3N4, and the characteristic peak of Co ions disappears, thereby proving the dispersion of Co on C3N4.

[0065] Figure 6 The infrared spectrum of Co-C3N4 prepared by the above method is shown in Figure 1. -1 The left and right sides are the triazine rings of C3N4, namely the out-of-plane bending peak of C6N7, 900cm -1 -1800cm -1 represents aromatic carbon-nitrogen heterocycles, 3000 cm -1 -3500cm -1 It represents the stretching vibration of the NH bond, which is related to the uncondensed amino group. And it can be observed that after Co doping, its infrared spectrum does not change, which indicates that Co does not destroy the structure of C3N4 itself.

[0066] Figure 7 The XPS spectrum of Co-C3N4 prepared by the above method is shown in FIG. Figure 7 The spectra of elements a and b correspond to those of element C and N, respectively. It can be seen that the structures of these two elements remain unchanged after doping with Co. However, since the Co doping level is very low, only 0.004% as measured by inductively coupled plasma optical emission spectroscopy, the distribution and bonding of Co cannot be seen in the XPS results.

[0067] Figure 8The fluorescence spectrum of Co-C3N4 prepared according to the above method is shown. The strongest emission wavelength of Co-C3N4 is at 450nm, which is consistent with that of C3N4. This demonstrates that the doping of Co element does not destroy the basic structure of C3N4. Furthermore, after reacting with NaHSO3 and H2O2, the fluorescence peak does not shift, and the intensity does not decrease. This proves that Co acts solely as a catalyst in the system and does not participate in the reaction.

[0068] Next, we will conduct experiments to verify whether the chemiluminescence enhancer obtained using the preparation method described above can catalyze the hydrogen peroxide-bisulfite chemiluminescence system, and how to achieve better luminescence effects by adjusting the order of addition of hydrogen peroxide and bisulfite and the concentrations of hydrogen peroxide and bisulfite. Details are described below.

[0069] Example 4

[0070] (1) By detecting the change in the luminescence intensity of the hydrogen peroxide-bisulfite system, it is proved that the chemiluminescence enhancer can enhance the luminescence of the system.

[0071] Detection of Co 2+ -NaHSO3-H2O2, C3N4-NaHSO3-H2O2 and Co-C3N4-NaHSO3-H2O2 systems were used to investigate whether Co-C3N4 had an enhancing effect on the chemiluminescence of the system.

[0072] The experimental conditions were: 1 mL of 0.02 mol / L NaHSO₃ and 100 μL of a 5 mg / mL Co-C₃N₄ aqueous dispersion were mixed, and then 1 mL of a 0.1 mol / L H₂O₂ aqueous solution was injected to obtain the Co-C₃N₄-NaHSO₃-H₂O₂ system. The NaHSO₃-H₂O₂ system was prepared without the addition of Co-C₃N₄.

[0073] like Figure 9 As shown in the figure, after adding Co-C3N4 to the NaHSO3-H2O2 system, the luminescence intensity increased significantly to about 23315 (counts). The luminescence intensity of the NaHSO3-H2O2 system with the addition of CoCl2·6H2O and C3N4 was about 235 (counts) and 2220 (counts), respectively.

[0074] Example 5

[0075] (2) The strongest luminescence intensity of the system was obtained by optimizing the synthesis conditions of the Co-C3N4 catalyst. At this time, the other reaction conditions were: 1 mL of 0.02 mol / L NaHSO3 aqueous solution was mixed with 100 μL of 5 mg / mL Co-C3N4 aqueous solution, and then 1 mL of 0.1 mol / L H2O2 aqueous solution was injected.

[0076] By adding different types of metal doping to obtain the best catalyst type, such as Figure 10 As shown, among the ten elements of cobalt, iron, nickel, chromium, copper, zinc, lanthanum, terbium, europium and holmium, cobalt has the highest light intensity of 23315, so the best choice is to use Co-doped C3N4 as a catalyst.

[0077] The strongest luminescence intensity can be obtained by optimizing the ultrasound duration, such as Figure 11 As shown in the figure, the strongest luminescence intensity can be obtained when the ultrasound time is 1 h.

[0078] The strongest luminescence intensity can be obtained by optimizing the doping amount of Co. Figure 12 As shown, 0.0005, 0.001, 0.005, and 0.01 mol of CoCl2·6H2O were added to 1 g of C3N4 respectively. When the input ratio was 0.001 mol CoCl2·6H2O: 1 g C3N4, the chemiluminescence intensity was the strongest.

[0079] Among them, Co is the central atom of Co-C3N4, and its doping amount will directly affect the rate and effect of the chemical reaction. Too high or too low Co doping amount may lead to poor catalytic effect. When the Co doping amount is 0.001mol, the best catalytic effect is achieved. The possible reason is that 0.001mol Co doping amount can form the optimal amount of active sites on the C3N4 surface, effectively increase the OO bond breaking rate of H2O2, accelerate the generation process of free radicals, and then promote SO3 - The production of , thereby promoting the chemiluminescence reaction.

[0080] Furthermore, at this doping ratio, the surface area and structure of the Co-C3N4 composite material reach an optimal balance, which helps to improve the activity of the catalyst, increase the number of active sites, and promote the reaction, ultimately leading to an increase in the chemiluminescence intensity.

[0081] Excessive Co doping may enhance the interaction between active sites, thereby reducing the reaction activity and leading to a decrease in chemiluminescence intensity. In addition, excessive Co doping may inhibit the formation of reaction intermediates or increase the formation of byproducts that are not conducive to the luminescence reaction, thereby reducing the overall luminescence effect.

[0082] However, too low a Co doping amount may lead to an insufficient number of active sites, limiting the rate and effect of the catalytic reaction and ultimately reducing the chemiluminescence intensity.

[0083] In summary, the input ratio of 0.001 mol CoCl₂·6H₂O:1 g C₃N₄ likely achieves an optimal balance between catalyst activity and surface structure, thereby maximizing chemiluminescence intensity. However, exceeding or falling below this ratio can lead to a decrease in catalytic effectiveness and affect the chemiluminescence reaction.

[0084] Example 6

[0085] (3) By optimizing the reaction conditions of the Co-C3N4-NaHSO3-H2O2 system, the strongest luminescence intensity of the system was obtained.

[0086] Next, the luminescence kinetics of the Co-C3N4-NaHSO3-H2O2 system was studied by adjusting the order of addition of NaHSO3 and H2O2. Under static conditions, the following three different addition orders were adopted:

[0087] Sequence 1, adding NaHSO3 into the mixed solution of Co-C3N4 and H2O2;

[0088] Sequence 2, adding H2O2 to the mixed solution of Co-C3N4 and NaHSO3;

[0089] Sequence 3, Co-C3N4 is added to the mixed solution of H2O2 and NaHSO3.

[0090] The Co-C3N4-NaHSO3-H2O2 systems obtained by the above three addition sequences all include 0.1 mol / L H2O2, 0.02 mol / L NaHSO3, and 0.5 mg Co-C3N4.

[0091] According to the above experimental findings, the order of adding reagents will affect the luminescence intensity of the Co-C3N4-NaHSO3-H2O2 system.

[0092] like Figure 13 As shown, sequence 2 obtains the highest luminescence intensity of the Co-C3N4-NaHSO3-H2O2 system, and this sequence is the optimal sample addition sequence.

[0093] Example 7

[0094] (4) The optimal reaction concentration of the luminescence system is obtained by adjusting the concentrations of hydrogen peroxide, bisulfite and catalyst.

[0095] Under the optimal sample addition order determined above, the chemiluminescence intensity of the system showed a certain correlation with the concentrations of NaHSO3, H2O2, and the catalyst. To obtain the best linear relationship, this example investigated the effects of NaHSO3, H2O2, and Co-C3N4 concentrations on chemiluminescence.

[0096] Fixed 0.1 mol·L -1 The addition amount of H2O2 and 0.5mg Co-C3N4. The concentration of NaHSO3 was investigated in the range of 0.01-0.1mol·L -1 .

[0097] Fixed 0.02 mol·L -1 The addition amount of NaHSO3 and 0.5mg Co-C3N4. The H2O2 concentration range is 0.01-10mol·L -1 .

[0098] Fixed 0.02 mol·L -1 NaHSO3 and 0.1 mol·L -1 The addition amount of Co-C3N4 was investigated in the range of 0.05-1 mg.

[0099] It should be noted that the concentrations of the aforementioned components are concentrations before mixing.

[0100] like Figure 14 As shown in the figure, when other conditions remain unchanged, the concentration of NaHSO3 is 0.02 mol·L -1 When the concentration of NaHSO3 is increased, the chemiluminescence intensity is the strongest. Continuing to increase the concentration of NaHSO3 will cause the luminescence intensity to gradually decrease.

[0101] like Figure 15 As shown in the figure, when other conditions remain unchanged, the concentration of H2O2 is 0.1 mol·L -1 When the concentration of H2O2 is increased, the chemiluminescence intensity is the strongest. Continuing to increase the concentration of H2O2 will cause the luminescence intensity to gradually decrease.

[0102] like Figure 16 As shown in Figure 2, when other conditions remain unchanged, the chemiluminescence intensity increases with the increase of Co-C3N4 concentration. For research cost considerations, the concentration of Co-C3N4 was set to 5 mg / mL in this paper.

[0103] When the concentrations of NaHSO₃ and H₂O₂ are too low, insufficient reactive oxygen species are generated, resulting in a weak luminescence signal. However, when the concentrations of NaHSO₃ and H₂O₂ are too high, the higher concentrations can quench the luminescence. For Co-C₃N₄, the catalytic effect increases significantly with increasing addition amount. However, increasing the concentration increases the research cost, so this paper did not use higher concentrations, instead selecting only 5 mg / mL.

[0104] The above experiments show that the optimal reaction conditions are 0.02 mol·L -1 NaHSO3, 0.1 mol·L -1H2O2, 5mg / mL Co-C3N4. The order of addition is to add the aqueous solution of H2O2 to the mixed solution of Co-C3N4 and NaHSO3 to obtain the Co-C3N4-NaHSO3-H2O2 system.

[0105] Next, we will explore the reaction mechanism

[0106] Example 8

[0107] (1) Conduct EPR experiments to test four free radicals, ·OH, ·O2 - , 1 O2 and SO3 - ,like Figure 17 As shown, it can be seen that the NaHSO3-H2O2 system will produce a small amount of four free radicals. After the addition of Co-C3N4 catalyst, the generation of these four free radicals is greatly increased, which can prove the catalytic effect of the catalyst.

[0108] (2) Whether dissolved oxygen participates in the reaction was investigated by bubbling N2 and O2 into the Co-C3N4-NaHSO3 aqueous solution for 30 min and comparing it with the case where no other gases were introduced but the solution was exposed to air. Figure 18 As shown, first of all, it can be determined that Co-C3N4-NaHSO3 will produce chemiluminescence, and through the N2, O2 bubbling experiment, it can be seen that the introduction of oxygen can enhance chemiluminescence, which shows that Co-C3N4 can indeed react with dissolved oxygen to produce free radicals, which further react with bisulfite to produce chemiluminescence.

[0109] (3) Use a filter to measure the chemiluminescence intensity of the Co-C3N4-NaHSO3 system every 25nm and determine its chemiluminescence spectrum.

[0110] like Figure 19 As shown, the Co-C3N4-NaHSO3 system emits broad-spectrum light in the range of about 400-600nm, which is consistent with the emission wavelength of SO2*, so it can be proved that the luminescence of this system comes from SO2*.

[0111] The above description describes the chemiluminescence enhancer's ability to catalyze the hydrogen peroxide-bisulfite system reaction, with this catalytic effect manifested in an increase in the luminescence intensity of the hydrogen peroxide-bisulfite system. Next, the reaction mechanism by which the chemiluminescence enhancer enhances the luminescence of the hydrogen peroxide-bisulfite system is described.

[0112] Based on experimental research and literature survey, the inventors found that the chemiluminescence principle of the Co-C3N4-NaHSO3-H2O2 system is as follows Figure 20 As shown. That is, H2O2 and NaHSO3 generate sulfite radical SO3 -When Co-C3N4 is added, the catalytic performance of Co-C3N4 can accelerate the electron transfer process in the NaHSO3-H2O2 system, thereby increasing the generation rate of multiple free radicals in the system.

[0113] As a catalyst, Co-C3N4 can catalyze the OO bond breakage of H2O2 in the NaHSO3-H2O2 system to generate ·OH, ·O2 and 1 O2. Thus promoting SO3 - In addition, Co-C3N4 can also react with dissolved oxygen-sodium bisulfite in small amounts to produce a small amount of SO3 - .

[0114] SO3 - Very active, easily forming excited SO2 * According to the above measured luminescence spectrum of the Co-C3N4-NaHSO3-H2O2 system, the wavelength is 400-600nm, which is consistent with * Characteristics of the spectral emission of SO2.

[0115] The reaction process of the Co-C3N4-NaHSO3-H2O2 chemiluminescence system is as follows:

[0116] H2O2+NaHSO3→·SO3 - +H2O+·OH (1)

[0117] HSO3 - +·OH→·SO3 - +H2O (2)

[0118] SO3 - +H2O2→HSO3 - + HO2 - (3)

[0119] HO2 - →H + + O2 - (4)

[0120] HO2 - +·OH→ 1 O2+H2O (5)

[0121] 2.SO3 - →SO2*+SO4 2- (6)

[0122] SO2*→SO2+hv (7)

[0123] Co(II)+H2O2→Co(III)+·OH (8)

[0124] Co(II)+O2→Co(III)+·O2 - (9)

[0125] O2 - +·OH+H + → 1 O2+H2O (10)

[0126] Co(III)+NaHSO3→Co(II)+·SO3 - (11)

[0127] SO3 - +O2→·SO5 - (12)

[0128] SO5 - +Co(III)→·SO4 - +·OH (13)

[0129] H2O2+C3N4→·OH+·O2 - (14)

[0130] Example 9

[0131] Next, we will conduct actual detection application. Glutathione, as a reducing substance, can be oxidized by hydrogen peroxide, thereby forming a competitive relationship with sodium bisulfite and reducing the chemiluminescence of the system. Based on this principle, glutathione detection was carried out. The detection effect is as follows: Figure 21 As shown in Figure 2, with the increase of glutathione concentration, the chemiluminescence signal gradually increased and showed good linearity. The linear range was 10 μM-500 μM, y=20.23x+174.679, R 2 =0.9978, and the detection limit was 7.221 μM.

[0132] This indicates that the single-atom chemiluminescence enhancer provided in this specification can linearly enhance the chemiluminescence intensity of the Co-C3N4-NaHSO3-H2O2 system containing glutathione. Therefore, the Co-C3N4-NaHSO3-H2O2 system established in this example can be used to detect glutathione based on chemiluminescence.

[0133] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. Use of a single-atom chemiluminescence enhancer in a chemiluminescence system, characterized in that: The chemiluminescence enhancer includes a transition metal single atom cobalt Co and a two-dimensional sheet nanomaterial C3N4; wherein the metal single atom cobalt Co is dispersed in the two-dimensional sheet nanomaterial C3N4, and the metal single atom cobalt Co is used as the central atom and C3N4 is used as a ligand to constitute the nano metal single atom dispersed material Co-C3N4 serving as a chemiluminescence enhancer; the ratio of C3N4 to the metal single atom cobalt Co is 1g:0.0005-0.01mol; the chemiluminescence system is an H2O2-NaHSO3 system, and the chemiluminescence enhancer is used to enhance the chemiluminescence intensity of the H2O2-NaHSO3 system.

2. The use according to claim 1, characterized in that The chemiluminescence enhancer is a nano-metal single-atom dispersion material Co-C3N4 synthesized by ultrasonic method using cobalt chloride hexahydrate and two-dimensional sheet nanomaterial C3N4 as raw materials; wherein, in the nano-metal single-atom dispersion material Co-C3N4, the ratio of C3N4 to metal single-atom cobalt Co is 1g:0.0005-0.001mol, and the two-dimensional sheet nanomaterial C3N4 is synthesized from melamine.

3. The use according to claim 1, characterized in that The method of using the chemiluminescence enhancer to enhance the luminescence of the H2O2-NaHSO3 system comprises the following steps: Prepare a 0.02 mol / L NaHSO3 solution, add the chemiluminescence enhancer, and obtain a mixed solution; H2O2 solution was added to the mixed solution to make the concentration of H2O2 in the mixed solution 0.1 mol / L and 0.5 mg of the chemiluminescence enhancer was contained in every 2 mL of the mixed solution.

4. A method for preparing a single-atom chemiluminescence enhancer for use as claimed in any one of claims 1 to 3, characterized in that: The steps include: Melamine was placed in a muffle furnace, and the temperature was increased to 550°C at a heating rate of 5°C / min. The melamine was calcined for 2 hours to obtain a calcined product. 1 mol / L nitric acid was then added to the calcined product and ultrasonically treated for 1 hour. The product was stirred for 24 hours to obtain a reaction solution. The reaction solution was filtered and washed, and then dried in an oven at 80°C for 12 hours to obtain C3N4 nanosheets. The C3N4 nanosheets and cobalt chloride hexahydrate were then dissolved in 40 mL of ethanol, pre-stirred for 6 hours, and then ultrasonically treated for 1 hour. The product was stirred for 24 hours, filtered, washed, and dried in an oven at 110°C for 24 hours to obtain Co-C3N4; wherein the feed ratio of the C3N4 to cobalt chloride hexahydrate was 1 g:0.0005-0.01 mol.

5. The method according to claim 4, characterized in that The feeding ratio of the C3N4 and cobalt chloride hexahydrate is 1g:0.0005-0.001mol.

6. The method according to claim 5, characterized in that The feeding ratio of the C3N4 and cobalt chloride hexahydrate is 1g:0.001mol.

7. The method according to claim 6, characterized in that The steps include: 4 g of melamine was placed in a crucible and then placed in a muffle furnace. The temperature of the muffle furnace was increased at a rate of 5°C / min, and the melamine was calcined at 550°C for 2 h to obtain a calcined product. The calcined product was ground in a mortar, and then ultrasonically treated with 1 mol / L nitric acid for 1 hour. The product was then placed in a reaction flask and stirred for 24 hours to mix evenly to obtain a first reaction solution. The first reaction solution was then filtered three times with 500 mL of water in a suction filter. The filter paper containing the filtered product was placed in a petri dish and then dried in an oven at 80°C for 12 hours to obtain C3N4 nanosheets. Add 40 mL of ethanol, 1 g of C3N4, and 0.001 mol of cobalt chloride hexahydrate into the reaction flask, mix well, and stir for 6 h to obtain a uniform solution. The reaction bottle was reacted under ultrasound for 1 hour, the frequency of ultrasonic treatment was 80 kHz, and the room temperature was maintained constant; after the ultrasonic reaction was completed, stirring was continued for 24 hours to make the product more uniform to obtain a second reaction solution; then the second reaction solution was placed in a suction filter and filtered three times with 500 mL of water; the filter paper containing the filtered product was placed in a culture dish and then placed in an oven and dried at 110° C. for 24 hours to obtain a chemiluminescence enhancer.

8. Use of a single-atom chemiluminescence enhancer in detecting glutathione, characterized in that: The use is the use of the chemiluminescence enhancer in combination with H2O2 and NaHSO3 in detecting glutathione; wherein the chemiluminescence enhancer is used to enhance the chemiluminescence intensity of the H2O2-NaHSO3 system, and the detection limit of the chemiluminescence enhancer in combination with H2O2 and NaHSO3 for detecting glutathione is 7.221 μM; wherein the chemiluminescence enhancer includes transition metal single atom cobalt Co and two-dimensional sheet nanomaterial C3N4; wherein the metal single atom cobalt Co is dispersed in the two-dimensional sheet nanomaterial C3N4, and the metal single atom cobalt Co is used as the central atom and C3N4 is used as the ligand to constitute the nano metal single atom dispersed material Co-C3N4 as a chemiluminescence enhancer; the ratio of C3N4 to metal single atom cobalt Co is 1g:0.0005-0.01mol.

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