Dual-mode optical probe based on Zn-mofs for the detection of hocl and h2o2

Abstract

The application discloses a kind of dual-mode optical probes based on Zn-MOFs and preparation and detection method of HOCl and H2O2, belongs to analysis and environmental monitoring field.The application is synthesized by simple "one-pot method" one-step dual-target detection optical probe BNBD@Zn-MOFs, selects 2,2-bipyridine-5,5-dicarboxylic acid (H2bpydc) and 2-amino benzimidazole (2-AMI) as organic ligand, wherein 2-AMI is as recognition unit can realize the visual colorimetric detection of HOCl, i.e.after adding HOCl, the color of probe solution can be judged by naked eye from light yellow to purple, and BNBD fluorophore can be specifically detected H2O2, and the effective encapsulation of Zn-MOFs to BNBD constructs the sensitive selective monitoring sensing platform of HOCl and H2O2 in environmental water sample.

Description

Technical Field

[0001] This invention relates to a method for detecting HOCl and H2O2, specifically to a method for simultaneous detection of HOCl and H2O2 using a metal-organic framework material optical probe (BNBD@Zn-MOFs) based on a compound encapsulated with an NBD-type fluorescent parent (BNBD), belonging to the field of analysis and environmental monitoring. Background Technology

[0002] Hypochlorous acid (HOCl) is a highly reactive oxidizing agent, synthesized by myeloperoxidase (MPO) secreted by phagocytes activated in inflammatory areas, catalyzing the reaction of hydrogen peroxide and chloride ions. Abnormal HOCl levels can lead to various diseases, including cardiovascular disease, arthritis, and cancer. Hydrogen peroxide (H2O2) is a metabolic product formed from the incomplete reduction of oxygen. Most endogenous H2O2 in cells is produced by superoxide dismutase (SOD) catalyzing the reaction of superoxide (·O2). - These substances are produced through disproportionation reactions. The significant impact of reactive oxygen species such as HOCl and H2O2 on human health and various diseases remains incompletely understood. Furthermore, hypochlorous acid and hydrogen peroxide are widely used in sterilization, disinfection, and medical applications, and the environmental pollution caused by the improper discharge and treatment of such wastewater is increasingly concerning. Therefore, developing a simple, sensitive, and effective monitoring technology for HOCl and H2O2 in living systems and environmental samples is of great importance.

[0003] Compared to traditional ROS analysis methods, including titration, high-performance liquid chromatography (HPLC), electrochemical analysis, and electron spin resonance (ESR), spectrophotometry, including ultraviolet spectrophotometry and fluorescence analysis, has attracted significant attention due to its advantages such as high sensitivity, fast response time, high selectivity, low cost, and ease of operation. Fluorescent probes can be combined with imaging technology for real-time in-situ monitoring of living organisms, showing potential application value in medical diagnosis and treatment. Meanwhile, visualization sensors developed based on ultraviolet spectrophotometry can achieve rapid naked-eye detection of target analytes, making them more suitable for on-site analysis of real-world environmental samples. Summary of the Invention

[0004] The purpose of this invention is to overcome the deficiencies in the prior art and to provide a dual-mode optical probe based on Zn-MOFs and a method for its preparation and detection of HOCl and H2O2.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] In a first aspect, the present invention provides a method for fabricating a dual-mode optical probe based on Zn-MOFs, as detailed below:

[0007] 100.0 mg of 2,2-bipyridine-5,5-dicarboxylic acid and 80.0 mg of 2-aminobenzimidazole were dissolved in 20.0 mL of water by sonication and stirred at room temperature. Then, 1.0 mL of 0.5 g / L BNBD solution was added. Finally, 1.0 mL of 1.5 M zinc nitrate solution was added dropwise to the resulting mixture. After precipitation, the mixture was stirred at room temperature for 2 h. The precipitate was collected by centrifugation and washed with methanol. The resulting pale yellow precipitate was the dual-mode optical probe constructed based on Zn-MOFs.

[0008] Preferably, the preparation method of the BNBD is as follows:

[0009] 502.0 mg of 4-chloro-7-nitro-2,1,3-benzoxadiazole was dissolved in 15.0 mL of anhydrous ethanol, then 310.0 mg of sodium acetate was added, followed by dropwise addition of 374.0 mg of methylpiperazine. The mixture was stirred overnight at room temperature. The resulting reaction mixture was filtered and washed several times with anhydrous ethanol to obtain an orange solid powder, the first compound. 199.0 mg of the first compound was dissolved in 10.0 mL of ethanol by heating, then 78.0 mg of sodium acetate and 136.0 mg of 4-(bromomethyl)phenylboronic acid were rapidly added, and the mixture was heated under reflux and stirred overnight. After the reaction was completed and cooled to room temperature, the resulting reaction mixture was filtered and the precipitate was washed several times with ethanol to obtain a pale yellow powder, which is BNBD.

[0010] Preferably, the centrifugation is performed at 8000 rpm for 15 min.

[0011] In a second aspect, the present invention provides a dual-mode optical probe based on Zn-MOFs, obtained by any of the preparation methods described in the first aspect.

[0012] Thirdly, the present invention provides a method for detecting HOCl and H2O2 using a dual-mode optical probe based on Zn-MOFs as described in the second aspect, as follows:

[0013] A dual-mode optical probe based on Zn-MOFs was added to the test solution containing HOCl. After adjusting the pH, the mixed solution was allowed to react fully at room temperature. The intensity of the new absorption peak at 560 nm was recorded using a UV-Vis spectrophotometer. The concentration of HOCl in the test solution was obtained by combining the linear relationship between the UV absorbance and different concentrations of HOCl.

[0014] A dual-mode optical probe based on Zn-MOFs was added to the test solution containing H2O2. After adjusting the pH, the mixed solution was shaken and incubated. Then, the fluorescence intensity at 542 nm, where the emission peak was located, was recorded using 470 nm as the excitation wavelength. Both the excitation and emission slits were fixed at 5 nm. Based on the fluorescence intensity at the 542 nm emission wavelength, combined with the linear relationship between quenching efficiency and different concentrations of H2O2, the concentration of H2O2 in the test solution was obtained.

[0015] Preferably, the concentration of the dual-mode optical probe based on Zn-MOFs in the mixed solution is 25.0 mg / L, and the pH is 7.0.

[0016] Preferably, for the test solution containing HOCl, the reaction time is 2 min.

[0017] Preferably, the test solution containing H2O2 is incubated with shaking at 40°C for 20 min.

[0018] Preferably, the pH of the mixed solution is adjusted by using 200.0 mM PBS phosphate buffer (pH = 7.0).

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] This invention synthesizes a dual-target optical probe, BNBD@Zn-MOFs, in a simple one-pot method. 2,2-Bipyridine-5,5-dicarboxylic acid (H2bpydc) and 2-aminobenzimidazole (2-AMI) are selected as organic ligands. 2-AMI serves as the recognition unit, enabling visual colorimetric detection of HOCl; upon the addition of HOCl, the probe solution changes color from pale yellow to purple, as can be observed with the naked eye. Meanwhile, the BNBD fluorophore specifically detects H2O2. The effective encapsulation of BNBD by Zn-MOFs constructs a sensitive and selective monitoring platform for HOCl and H2O2 in environmental water samples. Attached Figure Description

[0021] Figure 1 Fluorescence and UV-Vis absorption spectra of BNBD@Zn-MOFs in the presence of different concentrations of H₂O₂ (A) and HOCl (B). BNBD@Zn-MOFs: 25.0 mg / L, PBS buffer: 20.0 mM, pH = 7.0, λ ex =470nm.

[0022] Figure 2(A) Effect of probe concentration on the fluorescence intensity of BNBD@Zn-MOFs at 542 nm in the presence and absence of H2O2; (B) Effect of probe concentration on the probe quenching efficiency caused by H2O2 (60.0 μM). F0 and F represent the fluorescence intensity of the probe BNBD@Zn-MOFs at 542 nm in the absence and presence of H2O2, respectively. BNBD@Zn-MOFs: 25.0 mg / L, PBS buffer: 20.0 mM, pH = 7.0, λex = 470 nm.

[0023] Figure 3 (A) Effect of pH on the fluorescence intensity of probe BNBD@Zn-MOFs at 542 nm; (B) Effect of pH on probe quenching efficiency caused by H2O2 (60.0 μM); (C) Effect of reaction time on the fluorescence intensity of probe before and after the addition of H2O2 and HOCl; (D) Effect of reaction time on the absorbance of probe before and after the addition of HOCl. F0 and F represent the fluorescence intensity of probe BNBD@Zn-MOFs at 542 nm in the absence and presence of H2O2, respectively. BNBD@Zn-MOFs: 25.0 mg / L, PBS buffer: 20.0 mM, pH = 7.0, λ ex =470nm.

[0024] Figure 4 (A) Linear relationship between (F0-F) / F0 and H2O2 concentration; (B) Linear relationship between probe absorbance at 560 nm and HOCl concentration. F0 and F represent the fluorescence intensity of probe BNBD@Zn-MOFs at 542 nm in the absence and presence of H2O2, respectively. BNBD@Zn-MOFs: 25.0 mg / L, PBS buffer: 20.0 mM, pH = 7.0, λ ex =470nm.

[0025] Figure 5 Interference and selectivity experiments of probe BNBD@Zn-MOFs for the detection of H2O2 (A,B) and HOCl (C,D). F0 and F represent the fluorescence intensity of BNBD@Zn-MOFs at 542 nm in the absence and presence of H2O2, respectively. The concentrations of H2O2 and HOCl were 60.0 μM and 20.0 μM, respectively, and the concentrations of other substances were 200.0 μM. The concentrations of BNBD@Zn-MOFs were 25.0 mg / L, the concentration of PBS buffer was 20.0 mM, the pH was 7.0, and the λ... ex =470nm. Detailed Implementation

[0026] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.

[0027] This invention provides a method for preparing a dual-mode optical probe (BNBD@Zn-MOFs) based on Zn-MOFs. The BNBD@Zn-MOFs are synthesized via a one-pot method, as detailed below:

[0028] 100.0 mg of 2,2-bipyridine-5,5-dicarboxylic acid and 80.0 mg of 2-aminobenzimidazole were dissolved in 20.0 mL of water by sonication and stirred at room temperature. Then, 1.0 mL of 0.5 g / L BNBD solution was added. Finally, 1.0 mL of 1.5 M zinc nitrate solution was added dropwise to the resulting mixture. A precipitate formed instantly in the container. The mixture was stirred at room temperature for 2 h, centrifuged (preferably 8000 rpm, 15 min), collected, and washed with methanol (3 times). The resulting pale yellow precipitate is the dual-mode optical probe constructed based on Zn-MOFs. In practical use, the resulting pale yellow precipitate can be redispersed in 10.0 mL of ultrapure water and stored at 4 °C for later use.

[0029] As a preferred embodiment of the present invention, the preparation method of BNBD is as follows:

[0030] 502.0 mg of 4-chloro-7-nitro-2,1,3-benzoxadiazole was dissolved in 15.0 mL of anhydrous ethanol, then 310.0 mg of sodium acetate was added, followed by dropwise addition of 374.0 mg of methylpiperazine. The mixture was stirred overnight at room temperature. The resulting reaction mixture was filtered and washed several times with anhydrous ethanol to obtain an orange solid powder, compound one. 199.0 mg of the obtained compound one was dissolved in 10.0 mL of ethanol by heating, then 78.0 mg of sodium acetate and 136.0 mg of 4-(bromomethyl)phenylboronic acid were rapidly added, and the mixture was heated under reflux and stirred overnight. After the reaction was completed and cooled to room temperature, the resulting reaction mixture was filtered and the precipitate was washed several times with ethanol to obtain a pale yellow powder, which is BNBD.

[0031] Utilizing the aforementioned dual-mode optical probe constructed based on Zn-MOFs, this invention also provides a method for detecting HOCl and H2O2 using this BNBD@Zn-MOFs optical probe. The specific detection method is as follows:

[0032] A dual-mode optical probe based on Zn-MOFs was added to the test solution containing HOCl. After adjusting the pH, the mixed solution was allowed to react fully at room temperature. The intensity of the new absorption peak at 560 nm was recorded using a UV-Vis spectrophotometer. The concentration of HOCl in the test solution was obtained by combining the linear relationship between the UV absorbance and different concentrations of HOCl.

[0033] In practical use, 200 μL of PBS phosphate buffer (200.0 mM, pH = 7.0), 10 μL of BNBD@Zn-MOFs solution (5.0 g / L), and a certain concentration of HOCl solution (0-150.0 μM) were added sequentially to a 2.0 mL colorimetric tube. The volume was then adjusted to 2.0 mL with ultrapure water, and the reaction was allowed to proceed for 2 min at room temperature. The absorption spectrum was then recorded using a UV-Vis spectrophotometer. The concentration of HOCl in the test solution was determined by combining the absorption spectrum and the linear relationship between the color change and different concentrations of HOCl.

[0034] A dual-mode optical probe based on Zn-MOFs was added to the test solution containing H2O2. After adjusting the pH, the mixed solution was shaken and incubated. Then, the fluorescence intensity at 542 nm, where the emission peak was located, was recorded using 470 nm as the excitation wavelength. Both the excitation and emission slits were fixed at 5 nm. Based on the fluorescence intensity at the 542 nm emission wavelength, combined with the linear relationship between quenching efficiency and different concentrations of H2O2, the concentration of H2O2 in the test solution was obtained.

[0035] In practical use, 200 μL of PBS phosphate buffer (200.0 mM, pH = 7.0), 10 μL of BNBD@Zn-MOFs solution (5.0 g / L), and a certain concentration of H2O2 solution (0-150.0 μM) were added sequentially to a 2.0 mL colorimetric tube. The volume was then adjusted to 2.0 mL with ultrapure water, and the tube was incubated at 40 °C with shaking for 20 min. Finally, the fluorescence intensity at the emission peak of 542 nm was recorded using 470 nm as the excitation wavelength, with the slit width set to 5 / 5 nm. Based on the fluorescence intensity at the 542 nm emission wavelength and the linear relationship between quenching efficiency and different concentrations of H2O2, the concentration of H2O2 in the test solution was obtained.

[0036] Example

[0037] This embodiment fabricates a dual-mode optical probe based on Zn-MOFs. The fabrication method includes the following steps:

[0038] (1) Synthesis of BNBD: 502.0 mg of 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) was dissolved in 15.0 mL of anhydrous ethanol, then 310.0 mg of sodium acetate was added, followed by dropwise addition of 374.0 mg of methylpiperazine. The mixture was stirred overnight at room temperature. The reaction mixture was then filtered and washed several times with anhydrous ethanol to obtain an orange solid powder, i.e., the first compound. Subsequently, 199.0 mg of the first compound was weighed and dissolved in 10.0 mL of ethanol by heating. Then, 78.0 mg of sodium acetate and 136.0 mg of 4-(bromomethyl)phenylboronic acid were quickly added, and the mixture was heated under reflux and stirred overnight. After the reaction was completed and cooled to room temperature, the reaction mixture was filtered and the precipitate was washed several times with ethanol to obtain a pale yellow powder, i.e., BNBD.

[0039] (2) Preparation of BNBD@Zn-MOFs optical probe (i.e., a dual-mode optical probe based on Zn-MOFs): 100.0 mg of 2,2-bipyridine-5,5-dicarboxylic acid and 80.0 mg of 2-aminobenzimidazole were dissolved in 20.0 mL of ultrapure water by sonication and stirred at room temperature. Then, 1.0 mL of 0.5 g / L BNBD solution was added. Finally, 1.0 mL of 1.5 M zinc nitrate solution was added dropwise to the mixed solution. A precipitate was formed instantly in the beaker. Stirring was continued at room temperature for 2 h. The precipitate was collected by centrifugation (8000 rpm, 15 min) and washed three times with methanol. The resulting pale yellow precipitate was redispersed in 10.0 mL of ultrapure water and stored in a refrigerator at 4 °C for later use.

[0040] Based on the BNBD@Zn-MOFs optical probe prepared above, this embodiment also verifies its response to HOCl and H2O2, as follows:

[0041] Add 200 μL of PBS phosphate buffer (200 mM, pH 7.0), 10 μL of LB NBD@Zn-MOFs solution (5.0 g / L), and a certain concentration of H2O2 solution or HOCl solution to a 2.0 mL colorimetric tube. Finally, bring the volume to 2.0 mL with ultrapure water, and incubate at 40 °C with shaking for 20 min or at room temperature for 2 min. Record the fluorescence spectrum or UV absorption spectrum at an excitation wavelength of 470 nm.

[0042] BNBD@Zn-MOFs exhibited a maximum fluorescence emission peak at 542 nm under optimal excitation wavelength of 470 nm. Figure 1It can be seen that when 0-500.0 μM H2O2 is added to the detection system, H2O2 quenches the fluorescence peak at 542 nm. However, after adding 0-150.0 μM HOCl, the intensity of the new absorption peak at 560 nm in the UV spectrum of BNBD@Zn-MOFs gradually increases, and the solution color gradually changes from pale yellow to purple. This allows for dual-mode determination of HOCl and H2O2 using the BNBD@Zn-MOFs optical probe. Based on the BNBD@Zn-MOFs optical probe prepared above, this embodiment also optimizes the probe's detection conditions (including probe concentration, pH, and response time), as follows:

[0043] As a dual-mode, dual-target fluorescence colorimetric detection system, the effects of fluorescent probe concentration, pH, and equilibration time on quenching efficiency or UV absorbance changes caused by H₂O₂ or HOCl are important optimization factors. For optimizing probe detection concentration, the fluorescence intensity and H₂O₂ fluorescence quenching efficiency of probe solutions with different concentrations (5 mg / L, 10 mg / L, 25 mg / L, 50 mg / L, 100 mg / L, 200 mg / L) were measured. Figure 2 As shown, the fluorescence intensity of BNBD@Zn-MOFs gradually increases with the increase of probe concentration, but the fluorescence quenching efficiency caused by H2O2 is the greatest when the probe concentration is 25.0 mg / L. Therefore, 25.0 mg / L can be used as the probe concentration for subsequent analysis and detection.

[0044] To optimize the pH conditions of the system, PBS buffer solutions of different pH values ​​(pH 3.5-9.0) were added to 25.0 mg / L BNBD@Zn-MOFs probe solutions, followed by the addition of 60.0 μM H2O2. After reacting for 20 min, the fluorescence intensity at 542 nm was measured. Figure 3 As shown in A and 3B, BNBD@Zn-MOFs exhibit stable fluorescence under acidic to weakly alkaline conditions, and the fluorescence quenching efficiency is highest under neutral pH conditions with H2O2. This also aligns with the physiological pH environment of organisms. Therefore, pH 7.0 was selected as the subsequent detection condition.

[0045] Equilibrium time is another important factor affecting fluorescence sensing systems. Different concentrations of H₂O₂ or HOCl were added to a 25.0 mg / L BNBD@Zn-MOFs probe solution, and the fluorescence intensity at 542 nm and the UV absorbance at 560 nm were recorded at different time points. Figure 3As shown in C and 3D, the fluorescence intensity of the probe at 542 nm and the UV absorbance at 560 nm remained stable within 60 min, and the probe could achieve complete response to H2O2 and HOCl within 20 min and 2 min, respectively. Therefore, 20 min and 2 min were selected as the equilibration time for further experiments.

[0046] Therefore, the optimal probe concentration was 25.0 mg / L, and the optimal pH was 7.0. The optimal reaction time for HOCl determination was 2 min, and the optimal reaction time for H2O2 determination was 20 min. Under the optimized experimental conditions, this example also tested the quantitative detection of HOCl and H2O2 using the BNBD@Zn-MOFs optical probe, as detailed below:

[0047] Add 200 μL of PBS phosphate buffer (200 mM, pH 7.0), 10 μL of LB NBD@Zn-MOFs solution (5.0 g / L), and a certain concentration of H2O2 solution (0-500.0 μM) sequentially to a 2.0 mL colorimetric tube. Finally, bring the volume to 2.0 mL with ultrapure water and incubate at 40 °C with shaking for 20 min. Finally, record the fluorescence spectrum with an emission peak at 542 nm using 470 nm as the excitation wavelength, with the slit width set to 5 / 5 nm.

[0048] Add 200 μL of PBS phosphate buffer (200.0 mM, pH = 7.0), 10 μL of LBNBD@Zn-MOFs solution (5.0 g / L), and a certain concentration of HOCl solution (0-150.0 μM) to a 2.0 mL colorimetric tube in sequence. Finally, bring the volume to 2.0 mL with ultrapure water and react at room temperature for 2 min. Record the absorption spectrum using a UV-Vis spectrophotometer.

[0049] The results showed that, Figure 4 As shown in Figure A, within the range of 0.05–100.0 μM, there is a good linear relationship between the quenching efficiency (F0–F) / F0 at 542 nm and the H2O2 concentration. The linear regression equation is (F0–F) / F0 = 0.00517c + 0.08964(R). 2 =0.9914), the detection limit is 15.3 nM (3σ / K); for colorimetric quantitative detection of HOCl; such as Figure 4 As shown in Figure B, with the addition of HOCl, the absorbance at 560 nm gradually increased. The linear range of absorbance value A and HOCl concentration was 0.5-30.0 μM, and the regression equation was A = 0.00499c + 0.04273(R). 2=0.9902), and the limit of detection (LOD) is 0.14 μM (3σ / K), which is far lower than the residual chlorine in disinfectants stipulated by the WHO (0.6 mg / L) and the threshold for residual free chlorine at the end of the pipeline in drinking water stipulated by the national standard (0.05 mg / L).

[0050] To investigate the selectivity of the BNBD@Zn-MOFs optical probe for HOCl and H2O2, common ions (Na+, Na+, and So2+) were tested. + ,K + ,Zn 2+ Mg 2+ Ca 2+ ,Fe 3+ ,Cl - NO3 - CO3 2- SO4 2- Antioxidants (Glu, GSH, Cys) and active substances ROS / RNS (NO, ONOO) - ,·O 2- (1O2,·OH,HOCl,H2O2), specifically as follows:

[0051] Add 200 μL of PBS phosphate buffer (200 mM, pH 7.0), 10 μL of LB NBD@Zn-MOFs solution (5.0 g / L), and solutions of anions, cations, antioxidants, and other active substances of a certain concentration to a 2.0 mL colorimetric tube. Finally, bring the volume to 2.0 mL with ultrapure water and incubate at 40 °C with shaking for 20 min. Record the fluorescence spectra with an emission peak at 542 nm using 470 nm as the excitation wavelength, with the slit width set to 5 / 5 nm.

[0052] Add 200 μL of PBS phosphate buffer (200.0 mM, pH = 7.0), 10 μL of LBNBD@Zn-MOFs solution (5.0 g / L), and solutions of anions, cations, antioxidants, and other active substances of a certain concentration to a 2.0 mL colorimetric tube. Finally, bring the volume to 2.0 mL with ultrapure water and react at room temperature for 2 min. Record the absorption spectrum using a UV-Vis spectrophotometer.

[0053] The results are as follows Figure 5 As shown. By Figure 5 As shown in A and 5B, BNBD@Zn-MOFs achieve specific recognition of H2O2 due to the redox reaction of the boric acid group. Other substances have no significant effect on the fluorescence intensity of the system, and the quenching effect of H2O2 on BNBD@Zn-MOFs is not affected even in the presence of other interfering substances. Figure 5The C and 5D results showed that only HOCl enhanced the absorption of BNBD@Zn-MOFs, changing the color from pale yellow to purplish-red. However, the presence of antioxidants (GSH, cys) significantly affected the HOCl response. Since the concentration of reducing substances in water is low, BNBD@Zn-MOFs can effectively detect and analyze HOCl in actual environmental water samples. These results strongly demonstrate that the dual-mode, bifunctional probe possesses good selectivity and anti-interference capabilities, showing broad application prospects in the simultaneous detection of H2O2 and HOCl in real water samples.

[0054] This embodiment also verifies the application of the BNBD@Zn-MOFs optical probe in the detection of HOCl and H2O2 in actual environmental water samples, as detailed below:

[0055] Two water samples, one from tap water and one from a lake, were collected. After simple filtration, the samples were spiked with different concentrations of HOCl and H2O2. The HOCl in the unspecified water sample was determined using the standard DPD colorimetric method, and the results are shown in Table 1. The HOCl in the unspecified water sample was determined using this method and the standard DPD colorimetric method, and the results were basically consistent. The recoveries of other spiked samples ranged from 92.4% to 107.0%, which is satisfactory.

[0056] Table 1. Detection of HOCl and H2O2 in water samples

[0057]

[0058] ND - Not detected, RSD - Relative standard deviation

[0059] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for fabricating a dual-mode optical probe based on Zn-MOFs, characterized in that, Specifically as follows: 100.0 mg of 2,2-bipyridine-5,5-dicarboxylic acid and 80.0 mg of 2-aminobenzimidazole were dissolved in 20.0 mL of water by sonication and stirred at room temperature. Then, 1.0 mL of 0.5 g / L BNBD solution was added. Finally, 1.0 mL of 1.5 M zinc nitrate solution was added dropwise to the resulting mixture. After precipitation, the mixture was stirred at room temperature for 2 h. The precipitate was collected by centrifugation and washed with methanol. The resulting pale yellow precipitate was the dual-mode optical probe constructed based on Zn-MOFs. The preparation method of the BNBD is as follows: 502.0 mg of 4-chloro-7-nitro-2,1,3-benzoxadiazole was dissolved in 15.0 mL of anhydrous ethanol, then 310.0 mg of sodium acetate was added, followed by dropwise addition of 374.0 mg of methylpiperazine. The mixture was stirred overnight at room temperature. The resulting reaction mixture was filtered and washed several times with anhydrous ethanol to obtain an orange solid powder, the first compound. 199.0 mg of the first compound was dissolved in 10.0 mL of ethanol by heating, then 78.0 mg of sodium acetate and 136.0 mg of 4-(bromomethyl)phenylboronic acid were rapidly added, and the mixture was heated under reflux and stirred overnight. After the reaction was completed and cooled to room temperature, the resulting reaction mixture was filtered and the precipitate was washed several times with ethanol to obtain a pale yellow powder, which is BNBD.

2. The method for fabricating a dual-mode optical probe based on Zn-MOFs according to claim 1, characterized in that, The centrifugation was performed at 8000 rpm for 15 min.

3. A dual-mode optical probe based on Zn-MOFs, obtained by the preparation method described in claim 1 or 2.

4. A method for detecting HOCl and H2O2 using the dual-mode optical probe based on Zn-MOFs as described in claim 3, characterized in that, Specifically as follows: A dual-mode optical probe based on Zn-MOFs was added to the test solution containing HOCl. After adjusting the pH, the mixed solution was allowed to react fully at room temperature. The intensity of the new absorption peak at 560 nm was recorded using a UV-Vis spectrophotometer. The concentration of HOCl in the test solution was obtained by combining the linear relationship between the UV absorbance and different concentrations of HOCl. A dual-mode optical probe based on Zn-MOFs was added to the test solution containing H2O2. After adjusting the pH, the mixed solution was shaken and incubated. Then, the fluorescence intensity at 542 nm, with the excitation wavelength of 470 nm, was recorded. Both the excitation and emission slits were fixed at 5 nm. Based on the fluorescence intensity at the emission wavelength of 542 nm, combined with the linear relationship between quenching efficiency and different concentrations of H2O2, the concentration of H2O2 in the test solution was obtained.

5. The method for detecting HOCl and H2O2 according to claim 4, characterized in that, The concentration of the dual-mode optical probe based on Zn-MOFs in the mixed solution was 25.0 mg / L, and the pH was 7.

0.

6. The method for detecting HOCl and H2O2 according to claim 4, characterized in that, For the test solution containing HOCl, the reaction time is 2 min.

7. The method for detecting HOCl and H2O2 according to claim 4, characterized in that, For the test solution containing H2O2, incubate with shaking at 40°C for 20 min.

8. The method for detecting HOCl and H2O2 according to claim 4, characterized in that, In the mixed solution, the pH was adjusted using 200.0 mM PBS phosphate buffer (pH=7.0).

Images