Preparation of PCN-224-based fluorescent probes and methods for detecting sulfite ions

Abstract

The present invention discloses the preparation of a fluorescent probe based on PCN‑224 and a method for detecting sulfite ions. The preparation method of the fluorescent probe includes: mixing KH2PO4 and PCN‑224 in a solvent and dispersing them uniformly to obtain a fluorescent probe dispersion based on PCN‑224 for detecting sulfite ions. The present invention forms a sensor with PCN‑224 and dihydrogen phosphate. Under the irradiation of 413nm excitation light, PCN‑224 has a strong emission peak at 650nm, and after forming a sensor with dihydrogen phosphate, different linear equations can be presented for sulfite in different concentration ranges, forming a sensor with bilinear characteristics. The present invention utilizes the change in fluorescence intensity of the fluorescent probe at 650nm to construct a sensor for SO3 2‑ The dual linear sensor has the advantages of high sensitivity, high selectivity and strong anti-interference ability.

Description

Technical Field

[0001] The present invention relates to the technical field of ion detection, and more specifically, to the preparation of a fluorescent probe based on PCN-224 and a method for detecting sulfite ions. Background Art

[0002] Sodium sulfite is an inorganic substance with strong reducing properties. It has an inhibitory effect on oxidases in plant foods and is widely used as a food additive to achieve the effect of food preservation. my country allows the addition of sodium sulfite as a preservative in plant foods such as candied fruit, fructose, bamboo shoots, and blackcurrant concentrate. Similarly, sodium sulfite, as a strong reducing agent, is also used for bleaching during agricultural product processing. However, excessive residual sulfite is easily hydrolyzed into sulfurous acid on the human mucosa, causing damage to the respiratory tract, causing allergic reactions and leading to acute symptoms and diseases such as asthma, respiratory lung cancer, and nervous system diseases. my country has strict regulations on the residual amount of sodium sulfite. The sodium sulfite in edible white sugar must be less than 0.1g / kg; the residual amount of fruit and vegetable juice and pulp must not exceed 0.05g / kg; the residual amount of potato starch must not exceed 0.03g / kg, etc. The World Health Organization (WHO) stated that the daily intake of sulfite ions in food is 0.7mg / kg relative to personal body weight.

[0003] Accurate analysis of sulfites in food is difficult due to the complexity of food ingredients. In order to protect people's physiological health, it is particularly important to accurately analyze and detect trace sulfites in food. At present, there are many different studies on the detection of sulfites at home and abroad. Most methods for detecting sulfites, including chromatography, electrochemical detection, etc., require expensive instruments or complex experimental processes, which are not suitable for rapid and large-scale detection of agricultural products and foods. In recent years, fluorescent probes have attracted much attention because of their simple operation, high sensitivity, and ability to obtain instant information.

[0004] Wang's research group studied and designed a ratiometric fluorescent probe for simultaneous detection of sulfite and bisulfite (Wang S, Cao, X, Gao, T, et al. A ratiometric upconversion nanoprobe forfluorometric turn-on detection of sulfite and bisulfite [J]. Mikrochim Acta, 2018, 185 (4): 218.). By modifying the upconversion nanoparticle β-NaYF_4, the ratiometric fluorescence detection of green emission and near-infrared emission was achieved. The near-infrared emission remained unchanged in this system, while the green fluorescence was restored in the presence of sulfite or bisulfite. The analytical detection range of the probe is 10-250μM, the detection limit is 0.14μM, and the detection can be completed within 40s.

[0005] A study used o-aminophenylboronic acid and ZnCl2 as raw materials to prepare zinc-boron co-doped carbon dots (ZnB-CDs) that can emit yellow fluorescence (535nm) through a one-step hydrothermal method (Ma Yunxia, ​​Chen Yonglei, Na Min, et al. Preparation of zinc-boron co-doped carbon dots and their application in the detection of sulfite [J]. Journal of Wuhan University (Science Edition), 2021, 67(01): 33-40.). Based on the phenomenon that sulfite reduces the surface defects of ZnB-CDs and causes fluorescence enhancement, a new method for fluorescence detection of sulfite was established. This method can detect sulfite in the pH range of 3.0-8.0, and there are two linear ranges, 4-50μM and 50-160μM, with a detection limit of 1.24μM.

[0006] Using thiourea anion receptors to modify gold nanoparticles to obtain two-photon excited fluorescent materials, the KentaroTOMITA research group analyzed and detected sulfate ions in aqueous solution, with a detection range of 10 -4 -10 -3 M (Tomita K, Ishioka, T, Harata, A. Development of an anion probe: Detection of sulfate ion by two-photon fluorescence of gold nanoparticles [J]. Analytical Sciences, 2012.). Zhang's group developed a new near-infrared fluorescent probe (Zhang Q, Zhang, Y, Ding, S, et al. Anear-infrared fluorescent probe for rapid, colorimetric and ratiometric detection of bisulfite in food, serum, and living cells [J]. Sensors and Actuators B: Chemical, 2015, 211: 377-384.) for colorimetric ratiometric fluorescence detection of sulfite anions. The probe has an intramolecular charge transfer effect and can detect HSO3 in water environment under mild conditions. - / SO3 2- Detection was achieved with a detection limit as low as 27nM.

[0007] However, the environment of food and agricultural products is complex. Fluorescent probes are easily interfered by other ingredients in food in complex detection environments. Most fluorescent probes currently studied still have problems such as poor sensitivity and lack of high selectivity. In order to solve these problems, some nanomaterials are studied as part of sensors as emerging fluorescent probes. In particular, metal-organic framework materials have become a research hotspot for fluorescent probes due to their easy synthesis, adjustable structure, and rich binding sites.

[0008] Metal-organic framework is an emerging material in recent years. It is a coordination polymer composed of metal clusters as nodes and organic ligands. It is an adjustable porous framework structure. Different metal-organic framework materials can be synthesized by changing metals or organic ligands according to needs, or the materials can be modified, encapsulated, coated and modified after synthesis. The powerful functionality of metal-organic framework materials has made them applicable in various fields such as catalysis, adsorption, sensing, drug delivery, and bioimaging.

[0009] As a framework material, MOFs have a regular porous structure. The pore size, porosity and particle size can be changed by changing its material composition and synthesis conditions. The superior porosity provides a pre-concentration effect for analytical detection, and improves the sensitivity of fluorescent probes to the detected object. Selectivity, which is equally important as sensitivity, is an important indicator of the performance of analytical detection sensors, and is also improved due to the unique structural characteristics of MOFs materials. In addition to using different substances coordinated by itself to achieve detection effects due to specific recognition of the detected object or target conditions, MOFs materials can also rely on structural characteristics such as molecular sieve effects, surface pore size, and porosity to identify substances. The porous structure of MOFs becomes a recognition receptor for other small molecules and ions, or a host for small molecules, thus giving fluorescent probes good selectivity. The application of MOFs in the field of sensors also utilizes its photoluminescence characteristics. The structure of MOFs materials includes various types of inorganic ions, metal clusters, and organic ligands, forming a complex system and a regular porous structure, which can trigger a variety of photoluminescence mechanisms. For example, FRET, DEE, PET, etc., achieve photoluminescence by completing ion exchange between organic ligands, inorganic ions and metal clusters through different mechanisms, or synthesize MOFs materials with fluorescent properties by combining materials with other substances to make them have fluorescent properties. A variety of simple and extensive luminescence mechanisms have expanded the applicability of MOFs as fluorescent probes. However, MOFs materials have not been applied to the detection of sulfite in the prior art. Based on the above advantages of MOFs materials, designing a sensor that can detect sulfite based on metal-organic framework materials has important significance and development prospects. Summary of the invention

[0010] One object of the present invention is to provide a method for preparing a fluorescent probe based on PCN-224. PCN-224 and dihydrogen phosphate form a sensor. Under the irradiation of 413nm excitation light, PCN-224 has a strong emission peak at 650nm, and after forming a sensor with dihydrogen phosphate, different linear equations can be presented for sulfite in different concentration ranges, forming a sensor with bilinear characteristics. The present invention utilizes the change in fluorescence intensity of the fluorescent probe at 650nm to construct a sensor for SO3 2- The dual linear sensor has the advantages of high sensitivity, high selectivity and strong anti-interference ability.

[0011] Another object of the present invention is to provide a method for detecting sulfite ions using a fluorescent probe based on PCN-224, which can achieve high selectivity for sulfite and a small detection limit by using a simple mechanism through MOF materials.

[0012] In order to achieve these purposes and other advantages of the present invention, a method for preparing a fluorescent probe based on PCN-224 is provided, comprising:

[0013] KH2PO4 and PCN-224 are mixed and dispersed uniformly in a solvent to obtain a fluorescent probe dispersion for detecting sulfite ions based on PCN-224.

[0014] Preferably, in the method for preparing the fluorescent probe for detecting sulfite ions based on PCN-224, the mass concentration of PCN-224 in the dispersion is 20 μg / mL.

[0015] Preferably, in the method for preparing the fluorescent probe for detecting sulfite ions based on PCN-224, the content of KH2PO4 in the dispersion is 0.06 μM.

[0016] Preferably, in the method for preparing the fluorescent probe for detecting sulfite ions based on PCN-224, the method for preparing PCN-224 is:

[0017] TCPP, ZrOCl2·8H2O and BA are added to a solvent and fully dissolved, then heated and stirred, and then dried to obtain a mixture. The mixture is washed with a solvent and dried to obtain PCN-224.

[0018] Preferably, in the preparation method of the fluorescent probe for detecting sulfite ions based on PCN-224, 0.2 mol of TCPP, 3.6 mol of ZrOCl2·8H2O and 216 mol of BA are added to 10 mL of DMF, fully dissolved by ultrasonication for 5 minutes, and then transferred to a hydrothermal reactor lined with polytetrafluoroethylene, heated and stirred at 120°C for 18 hours, then placed in an oven and heated at 120°C for 18 hours to obtain a dark purple mixture, the mixture is washed 2-3 times with DMF, and dried to obtain a purple solid PCN-224.

[0019] The method for detecting sulfite ions using the fluorescent probe comprises:

[0020] Step 1: Add different concentration gradients of SO3 to the dispersion 2- Solution, detect fluorescence intensity, SO3 2- The concentration is the horizontal axis, and the fluorescence intensity of the sensor when the excitation wavelength is 413nm is the vertical axis. 2- The linear relationship between the concentration and the fluorescence intensity value is obtained to obtain a working curve, and a linear equation is obtained through the working curve;

[0021] Step 2: Add a certain amount of sample of unknown concentration to the dispersion, detect the fluorescence intensity of the solution after a certain period of time, substitute the fluorescence intensity value of the solution into the linear equation to obtain the concentration of the sulfite solution in the sample.

[0022] Preferably, in the method for detecting sulfite ions using a fluorescent probe, in the step one, linear equation one Y=1261.03519X+13344.35767 and linear equation two Y=125.11186X+17765.21932 are obtained through the working curve, the linear range of linear equation one is 0.01-4.00 μM, the linear range of linear equation two is 4.00-18.00 μM, and the detection limit is 3.8 nM. In the step two, the fluorescence intensity value of the solution is substituted into linear equation one or linear equation two to obtain the concentration of the sulfite solution in the sample.

[0023] Preferably, in the method for detecting sulfite ions using a fluorescent probe, in step 1, SO3 with different concentration gradients is added to 4 mL of PCN-224 dispersion having a mass concentration of 20 μg / mL and a KH2PO4 content of 0.06 μM. 2- Solution, detect fluorescence intensity, establish SO3 2- The linear relationship between concentration and fluorescence intensity value was obtained to obtain the working curve.

[0024] Preferably, in the method for detecting sulfite ions using a fluorescent probe, in step 2, the fluorescence intensity of the solution is detected after 4 minutes.

[0025] The present invention has at least the following beneficial effects:

[0026] The present invention uses metal zirconium as the metal node of the metal-organic framework and porphyrin as the organic ligand to synthesize the PCN-224 metal-organic framework material with photoluminescence properties, and designs a bilinear sensor that can achieve fluorescence enhancement effect on sulfite. 3- Has strong fluorescence response, PO4 3- It can specifically recognize PCN-224, greatly enhancing the fluorescence of PCN-224, and PCN-224 also has a fluorescence response to changes in pH. - The root is used as an auxiliary material and combined with PCN-224 to form a sensor, using SO3 2- The strong reducing robbing system H2PO4 - The proton hydrogen is reduced to HPO4 2- and PO4 3- .HPO4 2- and PO4 3- It produces specific recognition with Zr6 in PCN-224 to achieve the fluorescence enhanced sensing effect. We found that under the irradiation of 413nm excitation light, PCN-224 has a strong emission peak at 650nm, and after forming a sensor with dihydrogen phosphate, it can present different linear equations for sulfite in different concentration ranges, forming a sensor with bilinear characteristics. The present invention uses the change of fluorescence intensity of the fluorescent probe at 650nm to construct a sensor for SO3 2- The dual linear sensor has the advantages of high sensitivity, high selectivity and strong anti-interference ability.

[0027] The present invention uses MOF materials and a simple mechanism to achieve high selectivity for sulfite when detecting it and also has a small detection limit.

[0028] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the ultraviolet-visible absorption spectrum and fluorescence spectrum of PCN-224 prepared by the present invention;

[0030] Figure 2 is a transmission electron microscope (TEM) image of PCN-224 prepared by the present invention;

[0031] Figure 3is an X-ray diffraction (XRD) pattern of PCN-224 prepared by the present invention;

[0032] Figure 4 is the working curve of the present invention;

[0033] Figure 5 The sensor of the present invention detects SO3 2- The action time diagram of

[0034] Figure 6 The sensor of the present invention is for SO3 2- Selective results graph. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0036] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0037] Example 1

[0038] The preparation method of the fluorescent probe based on PCN-224 comprises:

[0039] KH2PO4 and PCN-224 are mixed and dispersed uniformly in a solvent to obtain a fluorescent probe dispersion for detecting sulfite ions based on PCN-224.

[0040] In the method for preparing the fluorescent probe for detecting sulfite ions based on PCN-224, the mass concentration of PCN-224 in the dispersion is 20 μg / mL. The optimal concentration of PCN-224 in this sensor is 20 μg / mL.

[0041] In the preparation method of the fluorescent probe for detecting sulfite ions based on PCN-224, the content of KH2PO4 in the dispersion is 0.06 μM. The optimal concentration of KH2PO4 in this sensing system is 0.06 μM.

[0042] In the method for preparing the fluorescent probe for detecting sulfite ions based on PCN-224, the method for preparing PCN-224 is as follows:

[0043] TCPP, ZrOCl2·8H2O and BA are added to a solvent and fully dissolved, then heated and stirred, and then dried to obtain a mixture. The mixture is washed with a solvent and dried to obtain PCN-224.

[0044] In the preparation method of the fluorescent probe for detecting sulfite ions based on PCN-224, 0.2 mol of TCPP, 3.6 mol of ZrOCl2·8H2O and 216 mol of BA are added to 10 mL of DMF, fully dissolved by ultrasonication for 5 minutes, and then transferred to a hydrothermal reactor lined with polytetrafluoroethylene, heated and stirred at 120°C for 18 hours, and then placed in an oven and heated at 120°C for 18 hours to obtain a dark purple mixture. The mixture is washed with DMF 2-3 times and dried to obtain a purple solid PCN-224, which is dispersed in a HEPES buffer solution and stored for later use.

[0045] The method for detecting sulfite ions using a fluorescent probe comprises:

[0046] Step 1: Add different concentration gradients of SO3 to the dispersion 2- Solution, detect fluorescence intensity, SO3 2- The concentration is the horizontal axis, and the fluorescence intensity of the sensor when the excitation wavelength is 413nm is the vertical axis. 2- The linear relationship between concentration and fluorescence intensity value is obtained to obtain the working curve, such as Figure 4 As shown, the linear equation is obtained through the working curve;

[0047] Step 2: Add a certain amount of sample of unknown concentration to the dispersion, detect the fluorescence intensity of the solution after a certain period of time, substitute the fluorescence intensity value of the solution into the linear equation to obtain the concentration of the sulfite solution in the sample.

[0048] In the method for detecting sulfite ions using a fluorescent probe, in the step one, a linear equation one Y=1261.03519X+13344.35767 and a linear equation two Y=125.11186X+17765.21932 are obtained through a working curve, the linear range of the linear equation one is 0.01-4.00 μM, the linear range of the linear equation two is 4.00-18.00 μM, and the detection limit is 3.8 nM. In the step two, the fluorescence intensity value of the solution is substituted into the linear equation one or the linear equation two to obtain the concentration of the sulfite solution in the sample.

[0049] In the method for detecting sulfite ions using a fluorescent probe, in step 1, SO3 with different concentration gradients is added to 4 mL of PCN-224 dispersion having a mass concentration of 20 μg / mL and a KH2PO4 content of 0.06 μM. 2- Solution, detect fluorescence intensity, establish SO3 2- The linear relationship between concentration and fluorescence intensity value was obtained to obtain the working curve.

[0050] In the method for detecting sulfite ions using a fluorescent probe, the fluorescence intensity of the solution is detected after 4 minutes in step 2.

[0051] experiment

[0052] 1. The optical properties of PCN-224 were characterized by UV-visible absorption spectroscopy and fluorescence spectroscopy. The results are as follows: Figure 1 As shown in a and 1b.

[0053] like Figure 1 As shown in a, there is a Soret characteristic absorption peak at a wavelength of 413 nm, and a Q band characteristic absorption peak of the porphyrin ligand at 500-700 nm. Figure 1 As shown in b, under irradiation with 413nm excitation light, there is a strong fluorescence emission peak at 650nm.

[0054] 2. The morphology and crystal structure of PCN-224 were characterized by transmission electron microscopy (TEM). Figure 2 shown.

[0055] like Figure 2 As shown, summarizing the average particle size of PCN-224, it can be seen that a rod-shaped material of 53.21 nm×125.74 nm (diameter×length) was synthesized.

[0056] 3. The morphology and crystal structure of PCN-224 were characterized by X-ray diffraction (XRD). The results are as follows: Figure 3 shown.

[0057] like Figure 3 As shown, the characteristic peak of PCN-224 is exhibited in the low-angle region of 2.5° to 15°.

[0058] 4. Explore the sensor detection of SO3 2- The effect time

[0059] Take several portions of 4 mL of PCN-224 dispersion containing a mass concentration of 20 μg / mL, add KH2PO4 solution to make its concentration 0.06 μM, and add different concentrations of SO3 2- The concentrations were 0, 2, 4, and 8 μM, and the addition of SO3 2- Fluorescence spectra before and after addition within 20 minutes, the results are as follows Figure 5 shown.

[0060] like Figure 5As shown in the figure, at the optimal PCN-224 and KH2PO4 concentrations, the action time of different concentrations (0, 2, 4, 8 μM) of sulfite on the sensor was studied. The fluorescence intensity increased sharply within 4 minutes after the addition of sulfite, and then stabilized after 4 minutes. The detection reaction time of the sensor to sulfite was 4 minutes.

[0061] 5. Selective Experiments

[0062] To investigate the sensor's response to SO3 2- To check whether the selectivity is good, take several portions of 4 mL of PCN-224 dispersion containing a mass concentration of 20 μg / mL, add KH2PO4 solution to make its concentration 0.06 μM, and incubate the sensor dispersion to allow it to fully react for 1 hour. Then add SO3 2- , Cl - 、HCO3 - 、SO4 2- Br - 、CO3 2- , K + 、NO2 - 、Na + , Ca 2+ , making SO3 2- The concentration ratio with other ions is 1:5. The fluorescence spectra after adding different ions are measured, and the results are as follows Figure 6 shown.

[0063] like Figure 6 As shown, under the optimal detection conditions, by adding other possible interfering ions such as SO3 2- , Cl - 、HCO3 - 、SO4 2- Br - 、CO3 2- , K + 、NO2 - 、Na + , Ca 2+ The sensor showed no obvious fluorescence enhancement response to interfering ions, which indicated that the sensing system had good selectivity and could selectively detect sulfite in complex samples.

[0064] 6. Actual sample testing

[0065] In order to evaluate the PCN-224 based sensor for SO3 2- The feasibility of detection was tested by adding a series of concentrations of SO3 2- Mixed with white sugar solution. Table 1 summarizes the sensor detection of SO3 2- Detailed results.

[0066] Table 1 Actual sample detection by spike recovery method

[0067]

[0068] As shown in Table 1, PCN-224 sensor detects SO3 in sugar 2- The recovery rate is 100.17%-106.25%, indicating that the sensor is effective in detecting SO3 2- It has certain potential in analytical detection applications.

[0069] 7. Summary

[0070] The present invention uses PCN-224 as a fluorescence sensor to achieve SO3 2- The detection mechanism of SO3 was discussed by using UV-visible absorption spectrum and fluorescence spectrum. 2- Detection sensitivity, SO3 2- By taking away H2PO 4- The proton hydrogen finally turns into PO4 3- , while free PO4 3- The specific recognition with PCN-224 significantly enhances the fluorescence intensity of PCN-224, thus achieving the effect of SO3 2- PCN-224 has a good detection effect on SO3 2- The detection has good selectivity and sensitivity, with a linear range of 0.01-4.00μM and 4.00-18.00μM, and a detection limit (LOD) of 3.8nM. The sensor is sensitive and shows good recovery rate through actual sample experiments, indicating that it has the potential to be used for SO3 2- Analyze the potential of detection.

[0071] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a fluorescent probe based on PCN-224, characterized in that: include: Mixing KH2PO4 and PCN-224 in a solvent and dispersing them uniformly to obtain a fluorescent probe dispersion for detecting sulfite ions based on PCN-224; Wherein, the preparation method of PCN-224 is: TCPP, ZrOCl2·8H2O and BA are added to a solvent and fully dissolved, then heated and stirred, and then dried to obtain a mixture. The mixture is washed with a solvent and dried to obtain PCN-224.

2. The method for preparing a fluorescent probe based on PCN-224 according to claim 1, characterized in that: The mass concentration of PCN-224 in the dispersion is 20 μg / mL.

3. The method for preparing a fluorescent probe based on PCN-224 according to claim 1, characterized in that: The content of KH2PO4 in the dispersion is 0.06 μM.

4. The method for preparing a fluorescent probe based on PCN-224 according to claim 1, characterized in that: 0.2 mol of TCPP, 3.6 mol of ZrOCl2·8H2O and 216 mol of BA were added to 10 mL of DMF and dissolved by ultrasonication for 5 min. Then, the mixture was transferred to a hydrothermal reactor lined with polytetrafluoroethylene and heated and stirred at 120 ℃ for 18 h. Then, the mixture was placed in an oven and heated at 120 ºC for 18 h to obtain a dark purple mixture. The mixture was washed with DMF 2-3 times and dried to obtain a purple solid PCN-224.

5. A method for detecting sulfite ions using a fluorescent probe prepared by the preparation method according to claim 1, characterized in that: include: Step 1: Add different concentration gradients of SO3 to the dispersion 2- Solution, detect fluorescence intensity, SO3 2- The concentration is the horizontal axis, and the fluorescence intensity of the sensor when the excitation wavelength is 413 nm is the vertical axis. 2- The linear relationship between the concentration and the fluorescence intensity value is obtained to obtain a working curve, and a linear equation is obtained through the working curve; Step 2: Add a certain amount of sample of unknown concentration to the dispersion, detect the fluorescence intensity of the solution after a certain period of time, substitute the fluorescence intensity value of the solution into the linear equation to obtain the concentration of the sulfite solution in the sample.

6. The method for detecting sulfite ions using a fluorescent probe as claimed in claim 5, characterized in that: In the step one, linear equation one Y=1261.03519X+13344.35767 and linear equation two Y=125.11186X + 17765.21932 are obtained through the working curve, the linear range of linear equation one is 0.01-4.00 μM, the linear range of linear equation two is 4.00-18.00 μM, and the detection limit is 3.8 nM. In the step two, the fluorescence intensity value of the solution is substituted into linear equation one or linear equation two to obtain the concentration of the sulfite solution in the sample.

7. The method for detecting sulfite ions using a fluorescent probe according to claim 5, wherein: In the step 1, different concentration gradients of SO3 were added to 4 mL of PCN-224 dispersion with a mass concentration of 20 μg / mL and a KH2PO4 content of 0.06 μM. 2- Solution, detect fluorescence intensity, establish SO3 2- The linear relationship between concentration and fluorescence intensity value was obtained to obtain the working curve.

8. The method for detecting sulfite ions using a fluorescent probe as claimed in claim 5, characterized in that: In the step 2, the fluorescence intensity of the solution is detected after 4 minutes.

Images