Preparation method and application of material for rapidly detecting H2O2

Abstract

The invention discloses a preparation method and application of a material for rapidly detecting H2O2. The preparation method comprises the following steps: synthesizing ZnGa2O4: Cr long-afterglow nanoparticles based PLNPs by using a hydrothermal method; the preparation method comprises the following steps: carrying out group modification and optimization on the surfaces of long-afterglow nano-particles, and after optimization, selecting hydroxyl groups to modify long afterglow, so as to synthesize the long-afterglow nano-particles PLNPs-OH with hydroxyl groups; the preparation method comprises the following steps: dissolving dried and ground PLNPs-OH in an MES buffer solution, mixing with an equivalent KMnO4 solution under strong stirring, and carrying out ultrasonic treatment until PLNPs (at) MnO2 with a nanoflower structure is synthesized, and at the moment, the mixed solution becomes brown and afterglow luminescence is quenched; the material for rapidly detecting H2O2 is obtained. The probe PLNPs (at) MnO2 with the nanoflower structure is constructed, H2O2 can be rapidly and sensitively detected in a solution system, meanwhile, H2O2 can be detected in a flat plate and paper-based system through the probe, use of expensive precise instruments is avoided through flat plate and paper-based detection, and the probe is suitable for developing field detection tools for H2O2.

Description

Technical Field

[0001] The present invention relates to the field of rapid detection technology, and in particular to a preparation method and application of a material for rapid detection of H2O2. Background Art

[0002] Currently, the methods reported for detecting H2O2 include electrochemical method, nanoenzyme detection method, non-enzyme sensor detection method, quantum dot sensor detection method, etc. Electrochemical method is easily interfered by complex samples and detection environment, and most of the above methods cannot avoid using fluorescence detection, while fluorescence spectrometry detection method is very susceptible to background fluorescence interference caused by the excitation light of the sample itself. Summary of the invention

[0003] The purpose of the present invention is to make up for the shortcomings of the prior art and provide a preparation method and application of a material for rapid detection of H2O2. The sensor based on PLNPs detects by afterglow luminescence, and does not require the use of additional excitation light. This feature can effectively avoid background fluorescence interference, and constructs a system for rapid and simple detection of H2O2 in a solution system. At the same time, the system can also detect H2O2 in a flat plate and paper-based system. Flat plate and paper-based detection avoid the use of expensive precision instruments, and are suitable for the development of on-site detection tools for H2O2.

[0004] The technical solution of the present invention: A method for preparing a material for rapid detection of H2O2, the method comprising the following steps: S1: Synthesis of ZnGa2O4: Cr long afterglow nanoparticles: ZnGa2O4: Cr long afterglow nanoparticles bare PLNPs were synthesized using a hydrothermal method; S2: Modification and optimization of the surface groups of long afterglow nanoparticles: The surface of long afterglow nanoparticles was modified with different groups, and the groups that could promote the uniform coating of manganese dioxide shell on the surface of long afterglow were screened. Finally, hydroxylation modification was selected: the synthesized bare PLNPs were hydroxylated with NaOH solution to obtain PLNPs-OH; S3: Synthesis of PLNPs@MnO2: The dried and ground PLNPs-OH was dissolved in MES buffer solution, and the KMnO4 solution was mixed with an equal amount of PLNPs-OH solution under stirring and subjected to ultrasonic treatment until PLNPs@MnO2 with a nanoflower structure was synthesized, the mixed solution turned brown and the afterglow luminescence was quenched; The material for rapid detection of H2O2 is obtained.

[0005] Preferably, the operation of step S1 is as follows: zinc nitrate and gallium nitrate are dissolved in ultrapure water, and then mixed with chromium nitrate solution. Under vigorous stirring, the pH of the mixed solution is adjusted to 8.0 with ammonia water, and the reaction precursor solution is placed in a high-pressure reactor for reaction; after the reaction is completed, the supernatant in the reactor is discarded, the precipitate is collected, the unreacted ions are removed by centrifugation, and the precipitate is washed with ultrapure water and ethanol respectively, vacuum dried overnight, and ground for use.

[0006] Further preferably, the operation of step S1 is: the molar ratio of zinc nitrate, gallium nitrate and chromium nitrate is 1: (2-2.5): (0.001-0.005), and the reaction conditions are 210-230 ° C for 15-25 h; preferably, the molar ratio of zinc nitrate, gallium nitrate and chromium nitrate is 1: 2: 0.004, and the reaction conditions are 220 ° C for 20 h.

[0007] Preferably, the modification and optimization of the surface groups of the long afterglow nanoparticles in step S2 are specifically performed as follows: PLNPs are added to NaOH, PEG, CS, and PAH solutions, ultrasonically dispersed, magnetically stirred, centrifuged to discard the supernatant, washed with ultrapure water and ethanol respectively, dried under vacuum, and ground to obtain long afterglow nanomaterials PLNPs (with -OH, -PEG, -CTAB, -CS, -PAH) modified with different groups; the effects of constructing PLNPs@MnO2 probes with long afterglow materials modified with different groups are compared. The more uniform the MnO2 coating on PLNPs@MnO2 and the less the amount used, the more sensitive the probe is to H2O2, and the formation of PLNPs@MnO2 is affected by the surface modification groups of the long afterglow. The specific operation of screening surface modification groups is as follows: PLNPs were added to NaOH solution, polyethylene glycol (PEG) solution, chitosan (CS) solution, and polyallylamine hydrochloride (PAH) solution, respectively, ultrasonically dispersed, magnetically stirred, centrifuged to discard the supernatant, washed with ultrapure water and ethanol, respectively, dried under vacuum and ground to obtain long afterglow nanomaterials PLNPs (-OH, -PEG, -CTAB, -CS, -PAH) modified with different groups. The long afterglow with different modification groups (P-OH, P-PEG, P-CTAB, P-CS, P-PAH) were stirred and mixed with an equal amount of KMnO4 solution, and ultrasonically assisted in the MES buffer system to form P-OH@MnO2, P-PEG@MnO2, P-CTAB@MnO2, P-CS@MnO2, P-PAH@MnO2, and the PL quenching effect, ultraviolet characteristic absorption peak, surface potential and morphology characteristics were investigated. The probes with good quenching effect and uniform surface shell coating and nanoflower structure were further screened out, i.e., probes obtained by long afterglow of surface modified with -OH.

[0008] The specific operation of hydroxylation modification is as follows: PLNPs are added to NaOH solution, ultrasonically dispersed, magnetically stirred, centrifuged to discard the supernatant, washed with ultrapure water and ethanol respectively, dried under vacuum and then ground to obtain hydroxylated long afterglow nanomaterial PLNPs-OH; Further preferably, the solid-to-liquid ratio of the PLNPs and the NaOH solution is (95-105): (95-105) mg mL -1 , NaOH solution concentration is 4-5.5 mmol L -1 , magnetic stirring for 10-14 h; Preferably, the solid-liquid ratio of the PLNPs and NaOH solution is 100:100 mg mL -1 , the concentration of NaOH solution is 5 mmol L -1 , magnetic stirring for 12 h.

[0009] Preferably, in step S3, the dried and ground PLNPs-OH is dissolved in MES buffer solution to obtain a PLNPs-OH solution, the PLNPs-OH solution is stirred with an equal volume of KMnO4 solution to obtain a mixed solution, and ultrasonic treatment is performed until the mixed solution turns brown and the afterglow luminescence is quenched to obtain PLNPs@MnO2.

[0010] Preferably, in step S3, the solid-to-liquid ratio of PLNPs-OH to MES buffer solution is 20:2 mg mL -1 , the concentration of KMnO4 solution was 3-8 mM, the ultrasonic treatment conditions were 30-40 KHz, and the time was 0.5-1.5 h.

[0011] The material obtained by the preparation method is used for detecting H2O2 in a solution system or detecting H2O2 in a test paper system.

[0012] Preferably, the material obtained by the preparation method is used for the detection of H2O2 in a solution system as follows: 5 μL of hydrogen peroxide standard solution (hydrogen peroxide solution concentrations: 0, 0.25, 0.4, 0.8, 1.0, 2.0, 2.5, 3.0, 4.0, 5.0 μM, final concentration) and sample solution were mixed with 2 mL of PLNPs@MnO2 solution (0.5 mg mL -1 ) were mixed, and the afterglow luminescence (PL) intensity of the solution at 700 nm was measured using a fluorescence spectrophotometer in phosphorescence mode under the conditions of an excitation light source of 254 nm and a slit width of 10 nm for excitation and emission.

[0013] Preferably, the material obtained by the preparation method is used for the detection of H2O2 in a test paper system as follows: 10 μL of PLNPs@MnO2 solution (5 mg mL -1 ) were mixed evenly with 10 μL of hydrogen peroxide standard solution (the concentrations of hydrogen peroxide solutions were: 160, 200, 300, 400, 600, 700, 800, 900, 1000 μM) or sample solution on the inner surface of a black 96-well plate cover, and observed and photographed in a dark-box four-purpose UV analyzer under an excitation light source of 254 nm, and then image processing was performed using image J software. The present invention has the following beneficial effects: ZGO:Cr PLNPs were prepared by a one-step hydrothermal method. MnO2 shells were grown in situ on the surface of ZGO:Cr PLNPs by an ultrasonic-assisted method to form PLNPs@MnO2 probes. Due to the presence of the MnO2 shell, the afterglow of PLNPs was quenched. When H2O2 appeared in the detection system, the probe was excited and the MnO2 shell decomposed, so that the afterglow luminescence intensity of PLNPs was quickly restored. The response sensitivity of PLNPs@MnO2 to H2O2 was affected by the MnO2 on its surface, that is, the more uniform the MnO2 shell coating, the less the amount used, and the better the afterglow quenching effect, the more sensitive PLNPs@MnO2 was to H2O2 detection and the lower the detection limit. However, the surface of barePLNPs has no active groups, which is not conducive to the reaction. Therefore, the modification groups on the long afterglow surface were optimized to obtain a more sensitive probe. In addition, the unique afterglow characteristics of PLNPs without in-situ excitation avoid fluorescence interference caused by continuous excitation of other substances in the solution system. At the same time, under the irradiation of a 254 nm ultraviolet light source, the red afterglow of PLNPs can be easily observed by the naked eye and in photos. Quantitative analysis can be achieved by using free mobile phone software to perform RGB analysis on the photos taken. The naked eye detection method of H2O2 is suitable for rapid detection on site without instruments, while solution detection can be used for complex matrix samples. The material of the present invention can not only detect the restored afterglow luminescence in the solution system with a fluorescence photometer, but also observe the restored afterglow luminescence with the naked eye on a flat plate and paper substrate. Therefore, we have successfully established a method for detecting H2O2 in a solution system and a naked eye detection system with fast reaction time and low detection cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 . Schematic diagram of the synthesis process of PLNPs@MnO2 and H2O2 detection based on PLNPs@MnO2 probe. Figure 2. Characterization of ZGO:CrPLNPs: (A) XRD pattern of ZGO:CrPLNPs; (B) TEM image of ZGO:CrPLNPs; (C) emission spectrum of ZGO:CrPLNPs (excitation light is 254 nm); (D) afterglow image of ZGO:Cr powder (the sample was re-excited with LED for 2 minutes after 1 hour). Figure 3 . Optimization of surface modification groups of ZGO:Cr PLNPs: PL emission spectra (A) and UV-absorption spectra (B) of PLNPs modified with different groups (-OH, -PEG, -CTAB, -CS, -PAH groups) coated with MnO2 shell; (C) Zeta potential diagram of P-OH@MnO2, P-PEG@MnO2, P-CTAB@MnO2, P-CS@MnO2, P-PAH@MnO2 and MnO2; (D) Photos of P-OH@MnO2, P-PEG@MnO2, P-CTAB@MnO2, P-CS@MnO2, P-PAH@MnO2.

[0015] Figure 4. TEM images of P-OH@MnO2 (A), P-PEG@MnO2 (B), and P-CTAB@MnO2 (C).

[0016] Figure 5. (A) UV-absorption spectra of MnO2 nanosheets (black line), PLNPs (blue line), and PLNPs@MnO2 (red line). (B) PL emission spectra of PLNPs with different surface modification methods. (C) PL emission spectra of PLNPs modified with MnO2 nanosheets at different KMnO4 dosages (50 - 200 μL); (D) PL emission spectra of PLNPs modified with MnO2 nanosheets at different ultrasonic times (0.5 -2.0 h), the concentration of PLNPs was fixed at 0.5 mg mL -1 .

[0017] Figure 6. TEM images of PLNPs@MnO2 prepared under different ultrasonic treatment times: (A) 0.5 h, (B) 1 h, (C) 1.5 h, (D) 2.0 h; TEM images of PLNPs@MnO2 prepared under different KMnO4 dosages: (E) 50 μL, (F) 80 μL, (G) 100 μL, (H) 150 μL, (I) 200 μL.

[0018] Figure 7: (A) PL emission spectra of PLNPs, PLNPs@MnO2, PLNPs@MnO2 with HCl, PLNPs@MnO2 with H2O2, and PLNPs@MnO2 with HCl and H2O2, (B) Photos of PLNPs, PLNPs@MnO2, and PLNPs@MnO2 with HCl and H2O2. Figure 8: (A) Luminescence emission spectra of PLNPs@MnO2 treated with different concentrations of H2O2 (0-1000 μM); (B) Relationship between F / F0 intensity and H2O2 at different concentrations of H2O2. (C) Image of PLNPs@MnO2 based on the detection of H2O2 by naked eye.

[0019] Fig. 9 Electron microscope image of ZGC@MnO2. DETAILED DESCRIPTION

[0020] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1: Optimization of the PLNPs@MnO2 preparation process 1.1 Synthesis of PLNPs ZnGa2O4: Cr (ZGO: Cr) PLNPs were synthesized by hydrothermal method. The specific steps are as follows: 1.0 mmol Zn(NO3)2 and 2.0 mmol Ga(NO3)3 were dissolved in 15 mL ultrapure water, then mixed with 0.004 mmol Gr(NO3)3 in a 50 mL round-bottom flask, and the pH value of the mixed solution was adjusted to 8.0 with NH3-H2O (28% by weight) and stirred at room temperature for 1 hour. The precursor solution was then placed in an autoclave and reacted at 220 °C for 20 hours. The final product was washed with ultrapure water several times and vacuum dried at 60 °C.

[0022] 1.2 Optimization of surface modification groups of PLNPs 100 mg of the prepared ZGO:Cr PLNPs were dispersed in NaOH solution, polyethylene glycol (PEG) solution, chitosan (CS) solution, and polyallylamine hydrochloride (PAH) solution (5 mmol L -1), stirred vigorously for 12 hours, centrifuged and discarded the supernatant, washed with ultrapure water and dried in vacuum. 20 mg of dried and ground PLNPs with different groups were dissolved in 2 mL of MES buffer solution (0.1 M). Subsequently, an equal volume of PLNPs (with -OH, -PEG, -CTAB, -CS, -PAH groups) was added to the 5 mM KMnO4 solution under strong stirring. Ultrasonic treatment was performed at room temperature for 1 hour until the PLNPs@MnO2 solution turned brown. The effects of different modification groups on the MnO2 shell coated on the surface of the long afterglow were investigated, and the modification groups with uniform coating and good quenching effect were screened out to obtain PLNPs@MnO2 with a nanoflower structure that was sensitive to H2O2, that is, the surface hydroxylated long afterglow was coated with the MnO2 shell.

[0023] 1.3 Synthesis of PLNPs@MnO2 Weigh 20 mg of dried and ground PLNPs-OH and dissolve it in 2 mL of MES buffer solution (0.1 M). Then, add an equal volume of PLNPs-OH to the 5 mM KMnO4 solution under vigorous stirring. Ultrasonic treatment was performed at room temperature for 1 hour until the PLNPs@MnO2 solution turned brown and the luminescence of PLNPs was quenched.

[0024] 1.3 H2O2 detection based on PLNPs@MnO2 in solution system A certain concentration of H2O2 standard solution (0, 0.25, 0.4, 0.8, 1.0, 2.0, 2.5, 3.0, 4.0, 5.0 μM, final concentration) was added to 2 mL of PLNPs@MnO2 (diluted to 0.5 mg mL with MES buffer). -1 ). The solution was then incubated for 1 min. The PL intensity was measured using the phosphorescence mode of a fluorescence spectrophotometer at an excitation wavelength of 254 nm. The slit widths for excitation and emission were fixed at 10 nm.

[0025] 1.4 Naked-eye detection of H2O2 based on PLNPs@MnO2 H2O2 naked eye detection was performed on a plate or test paper. 10 μL PLNPs@MnO2 solution (5 mg mL -1) were mixed with 10 μL H2O2 standard solution (H2O2 concentrations were 0, 160, 200, 300, 400, 600, 700, 800, 900, 1000 μM). Then, PL was observed and photographed under 254 nm excitation in a UV light box. The sample images were then processed using Image J software.

[0026] 2.1 Design and principle of H2O2 determination Figure 1 shows the synthesis diagram of PLNPs@MnO2 and the detection principle diagram of H2O2. In order to overcome the problem of spontaneous fluorescence interference encountered in traditional fluorescence detection, ZGO: Cr PLNPs with near-infrared luminescence were used as detection signal probes. ZGO: Cr PLNPs were prepared by hydrothermal method. MnO2 shell was generated in situ on the surface of ZGO: Cr PLNPs by ultrasonic-assisted method to form PLNPs@MnO2 probe. In order to further improve the response sensitivity of the probe to H2O2, the modified groups on the surface of PLNPs were first optimized, and the probe constructed by hydroxylation-modified long afterglow was screened out. The MnO2 shell on the surface was evenly coated, with good quenching effect, showing a clear nanoflower structure. Due to the presence of MnO2 shell, the luminescence of PLNPs was quenched. When H2O2 appeared in the detection system, MnO2 was decomposed, so that the afterglow luminescence of PLNPs was quickly restored. The use of PLNPs avoids the spontaneous fluorescence interference caused by in situ excitation in the solution system. In addition, under 254 nm UV light, the red afterglow of PLNPs can be easily observed by the naked eye and photos. Therefore, the photos taken can also be analyzed by RGB using free mobile phone software to achieve quantitative analysis. The naked eye detection of H2O2 is suitable for rapid on-site screening without instruments, while the solution detection can be used for samples with complex matrices.

[0027] 2.2 Characterization of ZGO:Cr PLNPs The prepared ZGO: Cr PLNPs have high crystallinity, present a standard cubic spinel structure ZnGa2O4 (PDF No.: 086-0413) (Figure 2A), good dispersion, and uniform size with a diameter of 11.07 ± 0.63 nm ( Figure 2 Figure 2C shows the strong emission peak of ZGO:Cr PLNPs at 700 nm in phosphorescence mode, which is attributed to Cr 3+ Typical R-type transition of ions ( 2 E→ 4 A2 transition), which proves that Cr 3+The luminescence properties of ZGO:Cr PLNPs were studied on an IVIS LuminaIII imaging system (PerkinElmer, USA). After the excitation light stops, the luminescence of ZGO:Cr PLNPs can last for 1 hour and can be repeatedly excited by red LED light ( Figure 2 D).

[0028] 2.3 Optimization of surface modification groups of ZGO:Cr PLNPs ZGO:Cr PLNPs have strong PL emission, but PL will be quenched after being coated with MnO2. The coating of MnO2 shell is very important for constructing probe PLNPs@MnO2. The more uniform the MnO2 shell coating is, the better the afterglow quenching effect of PLNPs is, and the more sensitive the response to H2O2 is. However, the MnO2 shell coating will be affected by the surface modification groups of PLNPs, so the appropriate surface groups are optimized and screened first. The results show that when constructing probes (P-CS-MnO2) and (P-PAH-MnO2) with PLNPs whose surface modification groups are -CS and -PAH, PL cannot be completely quenched, while the probes (P-OH-MnO2, P-PEG-MnO2, P-CTAB-MnO2) constructed with PLNPs whose surface is modified with -OH, PEG and CTAB show good quenching effect (Figure 3A), indicating that the MnO2 shell can be well wrapped on the PLNPs modified with -OH, PEG and CTAB. The absorption spectrum also shows that the surfaces of P-OH-MnO2, P-PEG-MnO2 and P-CTAB-MnO2 have characteristic peaks of MnO2 (Figure 3B). Zeta potential results and photos observed with the naked eye show that PLNPs modified with these three groups (-OH, PEG and CTAB) can be well coated by the MnO2 shell because the MnO2 shell exhibits strong negative charge ( Figure 3 C), the solution is brown in color ( Figure 3 D). TEM results show that when PLNPs are modified with -OH groups (PLNPs@MnO2), the MnO2 shell is more uniformly coated and forms a clear "nanoflower" structure ( Figure 4 ). Therefore, in subsequent experiments, PLNPs modified with -OH groups were selected. PLNPs@MnO2 also refers to the probes formed by modifying PLNPs with -OH groups and then coating them with MnO2 shells.

[0029] Figure 5A compares the UV-visible absorption spectra of PLNPs, MnO2, and PLNPs@MnO2. ZGO:Cr PLNPs have a wide absorption range between 300 nm and 600 nm, while MnO2 has a distinct characteristic absorption peak at 400 nm. After being coated with the MnO2 shell, PLNPs@MnO2 exhibits a new broad absorption band near 400 nm. To further prove that the MnO2 shell is coated on the surface of PLNPs, rather than just physically mixed, the afterglow quenching effects of PLNPs@MnO2 and PLNPs physically mixed with MnO2 nanosheets were compared ( Figure 5 B). In the solution of PLNPs+MnO2, the afterglow luminescence is partially weakened, while the afterglow luminescence of PLNPs@MnO2 is almost completely quenched. The reason may be that the in-situ growth of MnO2 and its uniform coating on the surface of PLNPs can maximize the absorption of long afterglow luminescence. PLNPs@MnO2 is prepared by ultrasound-assisted KMnO4 to form MnO2 flakes and in-situ coating on the surface of PLNPs. Therefore, the amount of KMnO4 and the ultrasonic time are important influencing factors. Figure 5C shows that the quenching effect is obvious after adding KMnO4, and the quenching efficiency is as high as 95% after 100 μL. Figure 5 D shows that after 1 h of ultrasonic treatment, the PL was almost completely quenched. Therefore, the addition of 100 μL KMnO4 and ultrasonic treatment for 1 h were used as the subsequent synthesis conditions.

[0030] 2.4 TEM image of PLNPs@MnO2 Figure 6 The formation process of PLNPs@MnO2 is shown from a microscopic perspective. Figures 6C and 6D demonstrate that the ultrasonic time and the amount of KMnO4 are the key to the preparation of PLNPs@MnO2 composite probes. After 0.5 h of ultrasonic treatment, the MnO2 shell began to form and gradually covered the ZGO:Cr PLNPs (Figure 6A). As the ultrasonic time increased, the MnO2 shell gradually decomposed and wrapped around the surface of the ZGO:Cr PLNPs, presenting a clear "nanoflower" shape at 1 h ( Figure 6 B). When the ultrasonic time increases, the structure of the "nanoflower" is destroyed and the MnO2 shell breaks (Figure 6C and Figure 6D). Therefore, 1 h was selected as the ultrasonic treatment time in subsequent experiments. In addition, the effect of the amount of KMnO4 on the morphology of PLNPs@MnO2 was also studied. When the amount of KMnO4 is too small, it is not enough to produce enough MnO2 shell ( Figure 6E and Figure 6F); when the amount of KMnO4 is too much, the MnO2 shell tends to become thicker (Figure 6H and Figure 6I). Therefore, it is more appropriate to fix the amount of KMnO4 at 100 μL (Figure 6G).

[0031] 2.5 Reaction of PLNPs@MnO2 to H2O2 The luminescence intensity of the PLNPs@MnO2 nanoflower composite material is "off", while H2O2 in a weakly acidic environment triggers the decomposition of the MnO2 shell, thereby restoring the afterglow luminescence intensity of PLNPs@MnO2. As shown in Figure 7A, the afterglow luminescence of PLNPs@MnO2 is almost completely quenched due to the coating of the MnO2 shell. Only when the environment is acidic or H2O2 exists alone, the afterglow luminescence recovery intensity is still weak, indicating that the decomposition of the MnO2 shell depends on acidity and H2O2. Only when the system is an acidic environment and H2O2 is present, the afterglow luminescence intensity will recover rapidly. Therefore, the PLNPs@MnO2 probe can be further used to monitor inflammatory sites in vivo. At the same time, it can be clearly seen from Figure 7B that the ZGO:Cr PLNPs solution is milky white, and after coating the MnO2 shell, the PLNPs@MnO2 turns brown. After reacting with H2O2 under acidic conditions, the solution returned to milky white, which further demonstrated the feasibility of PLNPs@MnO2 for H2O2 sensing.

[0032] 2.6 Response of PLNPs@MnO2 to H2O2 In the presence of H2O2, the afterglow luminescence intensity of PLNPs@MnO2 gradually recovered, and the increase in intensity was positively correlated with the concentration of H2O2. In the range of 0 to 5 μM, the recovered PL intensity F / F0 (F: PL intensity at 700 nm caused by H2O2, F0: PL intensity of PLNPs@MnO2) showed a good linear relationship with the H2O2 concentration, and the linear regression equation was F / F0 = 6.284X - 0.5727 (R 2 = 0.9962) (Figure 8B). The limit of detection (LOD) (3s) was calculated to be 0.079 μM. In addition, this method also enables the detection of H2O2 by naked eye photography. Since the naked eye can detect the red afterglow, we used ImageJ software to analyze the RGB image and calculate the luminescence intensity of the red part. The intensity of the red part is positively correlated with the H2O2 concentration (160-1000 μM) (Figure 8C). Although the sensitivity of naked eye detection is not as good as that of instruments, its advantage is that H2O2 can be detected without the aid of any precision instruments, which greatly reduces the cost and has good application prospects.

[0033] In practical application, we calculated the recovery rate by adding H2O2 standard solution to the actual sample, and the results are shown in Table 1. The results show that the method developed based on PLNPs and MnO2 is suitable for the analysis of actual samples.

[0034] Table 1. Detection of H2O2 in spiked samples

[0035] Comparative Example 1 ZnGa2O4:Cr (ZGC) long afterglow nanoparticles were synthesized by a hydrothermal method combined with a high-temperature calcination method. The conditions for synthesizing long afterglow are: first, the hydrothermal method is to mix zinc nitrate: gallium nitrate: chromium nitrate solution in a ratio of 1:2:0.004 and react at 220 ℃ for 10 h. The hydrothermally synthesized long afterglow was calcined at 750 ℃ ​​for 4 h to obtain long afterglow nanoparticles with no surface group modification. Probe synthesis: The long afterglow nanoparticles ZGC were directly mixed with 2.5mM KMnO4, and after ultrasonic treatment for 30 min, the MnO2 shell was directly modified on the surface of the long afterglow to construct a probe ZGC@MnO2 that responds to H2O2. The probe ZGC@MnO2 that responds to H2O2 was constructed.

[0036] The result is the synthesis of ZGC long afterglow nanomaterials with near-infrared luminescence and an emission peak at 680-730 nm. After calcination, the particle size is about 30 nm and the afterglow can last for 30 minutes. The constructed probe ZGC@MnO2 shows a positive correlation response to H2O2 in the range of 0-1 mM.

[0037] Comparative Example 2 Based on 1.1-1.3 in Example 1, the difference is that our long afterglow has a strong near-infrared afterglow without high-temperature calcination, which is sufficient for detection needs. The long afterglow synthesized directly by the hydrothermal method (220 ℃, 20 h) has better afterglow performance, and the afterglow can last for 1 hour (Figure 1D), and the particle size is smaller (about 11 nm) (Figure 1B), the dispersibility is better, and it is more conducive to subsequent modification. In the long afterglow synthesis method in Comparative Example 1, the particle size of the long afterglow after hydrothermal and calcination is about 30nm, and after calcination, the morphology of the long afterglow will also be irregular, easy to aggregate, and not conducive to subsequent modification.

[0038] Example 3 Based on 1.1-1.2 in Example 1, the difference is that we modified the surface groups of the long afterglow directly synthesized by hydrothermal method and optimized the effect of the modified groups on the manganese coating. The modified long afterglow can make the manganese dioxide shell coating more uniform, forming a nanoflower structure (Figure 2B), thereby improving the response sensitivity of the probe to hydrogen peroxide. In Comparative Example 1, the probe ZGC@MnO2 is obviously coated with an uneven shell, and a large piece is covered on the surface of the long afterglow (Figure 9). The linearity of the probe is 0-5 μM in solution and 160-1000 μM on the plate. In Comparative Example 1, the concentration of H2O2 that can be identified is in the mM range, and ours is in the μM range, and the sensitivity is greatly improved. In addition to being used in solution, we can also directly use a plate to detect H2O2 with the naked eye.

[0039] Table 2 Comparison of H2O2 detection results between other methods and our method

[0040] Among them: [1] L. Zhao, JJ Song, Y. Xue, XH Zhao, YJ Deng, Q. Li,YZ Xia, Green Synthesis of Ag-Au Bimetallic Nanoparticles with Alginate forSensitive Detection of H2O2, Catalysis Letters, 148 (2018) 3248-3256, http: / / dx.doi.org / 10.1007 / s10562-018-2522-1. [2] M. Shafa, I. Ahmad, S. Hussain, M. Asif, Y. Pan, R. Zairov, AAAlothman, M. Ouladsmane, Z. Ullah, N. Ullah, C. Lai, U. Jabeen, Ag-Cunanoalloys: An electrochemical sensor for H2O2 detection, Surfaces andInterfaces, 36 (2023), http: / / dx.doi.org / 10.1016 / j.surfin.2022.102616. [3] W.F. Liu, L. Yin, Q. Jin, Y.M. Zhu, J. Zhao, L.B. Zheng, Z.H.Zhou, B. Zhu, Sensing performance of a self-powered electrochemical sensorfor H2O2detection based on microbial fuel cell, Journal of ElectroanalyticalChemistry, 832 (2019) 97-104, http: / / dx.doi.org / 10.1016 / j.jelechem.2018.10.045. [4] X.M. Wang, Y. Luo, H. Xu, D. Li, Y.H. Wang, para -HydroxyThiophenol-Coated CdSe / ZnS Quantum Dots as a Turn-On Fluorescent Probe forH2O2Detection in Aqueous Media, Australian Journal of Chemistry, 71 (2018)971-977, http: / / dx.doi.org / 10.1071 / ch18207. [5] F. Vetr, Z. Moradi-Shoeili, S. Ozkar, Mesoporous MnCo2O4 withefficient peroxidase mimetic activity for detection of H2O2, InorganicChemistry Communications, 98 (2018) 184-191, http: / / dx.doi.org / 10.1016 / j.inoche.2018.10.024. As can be seen from Table 2, the detection linear range of the present invention is wider and the detection limit is lower. In summary, the present invention has developed a non-autofluorescence detection method and a naked eye detection method for H2O2 in a solution system. First, a long afterglow nanomaterial was synthesized by a one-step hydrothermal method, and the surface groups suitable for uniform coating of manganese dioxide were screened out by modification and optimization of the groups. The MnO2 shell was uniformly coated on the PLNPs modified with hydroxyl groups by an ultrasonic-assisted method to construct a nanoflower structured probe PLNPs@MnO2. Based on the afterglow luminescence characteristics of PLNPs without in-situ excitation, the chemical reaction of MnO2 and H2O2, and the probe of the nanoflower structure, the detection method shows high sensitivity in the solution system without autofluorescence interference. In addition, PLNPs will produce red (sensitive to the naked eye) under irradiation with a 254 nm ultraviolet light source, and H2O2 can be visually detected without complex instruments. Therefore, the present invention provides two H2O2 optical sensing detection strategies based on PLNPs, which can meet the requirements of different application scenarios.

[0041] The above are only relatively preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a material for rapid detection of H2O2, characterized in that: The preparation method comprises the following steps: S1: Synthesis of ZnGa2O4: Cr long afterglow nanoparticles: ZnGa2O4: Cr long afterglow nanoparticles bare PLNPs were synthesized using a hydrothermal method; S2: Modification and optimization of surface groups of long afterglow nanoparticles: The synthesized bare PLNPs were hydroxylated with NaOH solution to obtain modified PLNPs; S3: Synthesis of PLNPs@MnO2: The dried and ground modified PLNPs were dissolved in MES buffer solution, and the KMnO4 solution was mixed with an equal amount of the modified PLNPs solution under stirring and subjected to ultrasonic treatment until PLNPs@MnO2 with a nanoflower structure was synthesized, the mixed solution turned brown and the afterglow luminescence was quenched; and a material for rapid detection of H2O2 was obtained.

2. The method for preparing a material for rapid detection of H2O2 according to claim 1, characterized in that: The specific operation of step S1 is as follows: zinc nitrate and gallium nitrate are dissolved in ultrapure water, and then mixed with chromium nitrate solution. Under vigorous stirring, the pH of the mixed solution is adjusted to 7.5-8.5 with ammonia water, and the reaction precursor solution is placed in a high-pressure reactor for reaction; after the reaction is completed, the supernatant in the reactor is discarded, the precipitate is collected, and the unreacted ions are removed by centrifugation, and the precipitate is washed with ultrapure water and ethanol respectively, vacuum dried, and ground to obtain ZnGa2O4: Cr long afterglow nanoparticles bare PLNPs.

3. The method for preparing a material for rapid detection of H2O2 according to claim 2, characterized in that: The operation of step S1 is as follows: the molar ratio of zinc nitrate, gallium nitrate and chromium nitrate is 1: (2-2.5): (0.001-0.005), and the reaction conditions are 210-230°C for 15-25 hours; preferably, the molar ratio of zinc nitrate, gallium nitrate and chromium nitrate is 1: 2: 0.004, and the reaction conditions are 220°C for 20 hours.

4. The method for preparing a material for rapid detection of H2O2 according to claim 1, characterized in that: The specific operation of step S2 for modification and optimization of the surface groups of long afterglow nanoparticles is as follows: PLNPs are added to NaOH solution, polyethylene glycol solution, chitosan solution or polyallylamine hydrochloride solution respectively, ultrasonically dispersed, magnetically stirred, centrifuged to discard the supernatant, washed with ultrapure water and ethanol respectively, dried under vacuum and ground to obtain long afterglow nanomaterials PLNPs modified with different groups.

5. The method for preparing a material for rapid detection of H2O2 according to claim 4, characterized in that: The solid-liquid ratio of the PLNPs, NaOH solution, polyethylene glycol solution, chitosan solution, and polyallylamine hydrochloride solution is (95-105): (95-105) mg mL -1 The concentrations of polyethylene glycol solution, chitosan solution, and polyallylamine hydrochloride solution were 4-5.5 mmol L -1 , magnetic stirring for 10-14 h.

6. The method for preparing a material for rapid detection of H2O2 according to claim 1, characterized in that: In the step S3, the dried and ground modified PLNPs are dissolved in a MES buffer solution to obtain a modified PLNPs solution, the modified PLNPs solution is stirred with an equal volume of a KMnO4 solution to obtain a mixed solution, and ultrasonic treatment is performed until the mixed solution turns brown and the afterglow luminescence is quenched to obtain PLNPs@MnO2.

7. The method for preparing a material for rapid detection of H2O2 according to claim 1, characterized in that: In step S3, the solid-to-liquid ratio of the modified PLNPs to the MES buffer solution is (18-22): 2 mg mL -1 , the concentration of KMnO4 solution was 3-8 mM, the ultrasonic treatment conditions were 30-40 KHz, and the time was 0.5-1.5 h.

8. The material obtained by the preparation method according to any one of claims 1 to 7 is used for detecting H2O2 in a solution system or detecting H2O2 in a test paper system.

9. The use according to claim 8, characterized in that: The material obtained by the preparation method is used for the detection of H2O2 in a solution system as follows: The hydrogen peroxide standard solution or sample solution was mixed with the PLNPs@MnO2 solution, and the afterglow luminescence intensity of the solution at 700 nm was measured using a fluorescence spectrophotometer in phosphorescence mode with an excitation light source of 254 nm and a slit width of 10 nm for excitation and emission.

10. The use according to claim 8, characterized in that: The material obtained by the preparation method is used for the detection of H2O2 in a test paper system as follows: The PLNPs@MnO2 solution and the hydrogen peroxide standard solution or sample solution were mixed evenly on the inner surface of the black 96-well plate cover, and observed and photographed in a dark box four-way UV analyzer under the condition of an excitation light source of 254 nm, and then the image was processed using the image J software.

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