A fluorescent probe for detecting perchlorate in water, preparation method and application thereof

Abstract

The present invention discloses a fluorescent probe for detecting perchlorate in water, a preparation method and an application thereof. The present invention synthesizes a perylene core derivative with adjustable hydrophilicity at the molecular level as a fluorescent probe for perchlorate by modifying the perylene molecule and adding pyridine with a long alkyl group. By optimizing the carbon chain length, a strong selective recognition of perchlorate is achieved, and the detection limit can reach 6.37nM (0.63ug / L), which is much lower than the limit of 70ug / L. Experiments have shown that the fluorescent probe has high selectivity and high sensitivity for perchlorate. The detection method of the present invention has the characteristics of wide detection linear range, low detection limit, strong anti-interference ability, simple operation, high efficiency and speed, and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical detection sensing, and in particular relates to a fluorescent probe for detecting perchlorate in water, a preparation method and an application thereof. Background Art

[0002] Perchlorate is an inorganic ion that is easily soluble in water, non-volatile, and persistent in the environment. It can combine with potassium, sodium, calcium, and a variety of ions including ammonium to form compounds. Due to its good solubility and stability in water, perchlorate easily contaminates surface water and groundwater and is widely present in natural water sources. In addition, based on these characteristics, perchlorate is also commonly found in many agricultural and animal products.

[0003] Although perchlorate has good solubility and can be quickly excreted from the body, due to its similar ionic radius to that of iodide ions, perchlorate ions can reversibly replace iodine in thyroid receptors, thereby reducing the secretion of T3 and T4 hormones and seriously affecting thyroid function.

[0004] Therefore, it becomes particularly critical to detect perchlorate ions in various samples (such as groundwater, propellants, explosives, and urine) in the presence of other anions. China's "Sanitary Standard for Drinking Water" (GB5749-2022) stipulates a limit of 70 μg / L for perchlorate in drinking water. The lower limit and the complex environment in the water source impose strict requirements on the highly sensitive and selective sensing of perchlorate.

[0005] At present, the detection methods of perchlorate include mass spectrometry, spectrophotometry, ion chromatography, Raman spectroscopy, etc. Among them,

[0006] Ion chromatography: It is the most common method for perchlorate detection in laboratories and one of the most commonly used methods for detecting perchlorate. Ion chromatography separates ions in the sample through an ion exchange column and then uses a detector (such as a conductivity detector) for quantitative detection. It is an efficient, sensitive and reliable method for analyzing perchlorate and other ion substances. The detection limit for perchlorate can reach 10 micrograms / liter, but it has disadvantages such as long detection time (>30 minutes) and the need for sample pretreatment.

[0007] Spectrophotometry: Spectrophotometry uses perchlorate to react with specific reagents to generate colored products, and then uses a UV-visible spectrometer to measure the absorbance for quantitative analysis. However, the sensitivity is relatively low, and the selectivity is low, making it difficult to apply to samples with complex background conditions.

[0008] Raman spectroscopy: Raman spectroscopy is a quantitative analysis method that detects the Raman scattering spectrum of perchlorate molecules under laser irradiation. This method has the advantages of being fast, non-destructive and highly sensitive, but it requires expensive instruments and equipment and is difficult to adapt to the requirements of large-scale samples and online detection.

[0009] Mass spectrometry: Mass spectrometry is based on the measurement of the motion trajectory and mass-to-charge ratio of ions in an electric field, combined with a mass analyzer to separate and detect these ions. Perchlorate is usually detected and analyzed in the form of molecular ions or their fragment ions in mass spectrometry. Mass spectrometry has a low detection limit for perchlorate, but mass spectrometry equipment is expensive, detection costs are high, and operation is complicated.

[0010] Although the above methods are effective, they are susceptible to interference, time-consuming, and costly. Therefore, there is an urgent need to develop a simpler, faster, more sensitive, and more selective method for detecting perchlorate. Summary of the invention

[0011] In view of the problems existing in the above-mentioned prior art, the object of the present invention is to provide a fluorescent probe for detecting perchlorate in water, a preparation method and application thereof.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] A first aspect of the present invention provides a method for preparing a fluorescent probe for detecting perchlorate in water, comprising the following steps:

[0014] S1. Synthesis of 3,6-dibromo-2,7-dihydroxynaphthalene:

[0015] Dissolve 2,7-dihydroxynaphthalene in acetic acid, then add bromine in acetic acid solution and water, and stir at 80-100° C. for 2-3 hours; add tin powder after all the solids are dissolved, continue heating and stirring for 10-12 hours, add water to quench the reaction after the reaction is completed, filter, wash with clean water, dry, and purify with a silica gel flash chromatography column to obtain 3,6-dibromo-2,7-dihydroxynaphthalene;

[0016] S2. Synthesis of tetrabromoperylenequinone:

[0017] Dissolve 2,7-dibromo-3,6-dihydroxynaphthalene in a mixture of methanol and water, then add KMnO 4 The solution was stirred at room temperature for 34 to 36 hours. After the reaction was completed, HCl solution was added dropwise to the reaction solution to adjust the reaction solution to acidity. The reaction solution was allowed to stand to precipitate solids. The solids were filtered and repeatedly washed with clean water, and then dried in vacuo to obtain tetrabromoperylenequinone.

[0018] S3. Synthesis of tetrabromotetrahydroxyperylene:

[0019]

[0020] Dissolve tetrabromoperylenequinone in methanol, add saturated sodium dithionite solution in an argon atmosphere, and react by stirring at room temperature. After the reaction is completed, add HCl solution dropwise to the reaction solution to adjust the reaction solution to acidity, let it stand, precipitate solid, filter the solid precipitate, wash it repeatedly with clean water, and dry it in vacuum to obtain tetrabromotetrahydroxyperylene;

[0021] S4. Synthesis of fluorescent probe:

[0022]

[0023] S41. Add tetrabromotetrahydroxyperylene, tetrabutylammonium bromide and potassium hydroxide into the dry 1,4-dioxane solution and dissolve them. 2 Ethyl bromide was added under atmosphere and stirred for reaction. After the reaction was completed, the mixture was extracted with water and dichloromethane, the organic phase was separated and the mixture was concentrated with anhydrous MgSO 4 Dry, filter, and remove the solvent under reduced pressure to obtain the probe precursor 1;

[0024] S42, 4-pyridinol and K 2 CO 3 Dissolve in N-methylpyrrolidone (NMP) at room temperature with stirring. 2 The probe precursor 1 was added at 40 °C and refluxed to react. After cooling to room temperature, the reaction mixture was poured into HCl, the precipitate was filtered, washed with water until neutral, dried in vacuo, and purified by column chromatography to obtain the probe precursor 2;

[0025] S43, dissolving the obtained probe precursor 2 and bromoalkane in DMF, wherein the chemical formula of bromoalkane is Br-C n H 2n+1 , where n is 1 to 9, and the reaction is allowed to proceed. After the reaction is completed, excess water is added and the reaction is filtered to obtain a fluorescent probe.

[0026] Preferably, in step S1, the dosage ratio of the 2,7-dihydroxynaphthalene, liquid bromine, water and tin powder is 8-10 g: 8-11 mL: 12-15 mL: 6-8 g.

[0027] Preferably, in step S1, the reaction temperature is 80-100°C and the reaction time is 2-3h;

[0028] The continuous stirring reaction time is 10 to 12 hours; the drying temperature is 55 to 65° C., and the drying time is 10 to 12 hours.

[0029] Preferably, in step S1, the eluent for purification by the silica gel flash chromatography column is a mixed solvent of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is 1 to 3:1.

[0030] Preferably, in step S2, the KMnO 4 The concentration of the solution is 0.02-0.05M, and the 2,7-dibromo-3,6-dihydroxynaphthalene, KMnO 4 The dosage ratio of the solution is 2-3g:0.3g-0.4g.

[0031] Preferably, in step S2, the stirring reaction time at room temperature is 34 to 36 hours, and the standing time is 1 to 2 hours.

[0032] Preferably, in step S3, the dosage ratio of tetrabromoperylenequinone to saturated sodium dithionite solution is 2-3 g: 2.2-3.2 g.

[0033] Preferably, in step S3, the stirring reaction time at room temperature is 20 to 24 hours, the standing time is 1 to 3 hours, the vacuum drying temperature is 50 to 60° C., and the drying time is 10 to 12 hours.

[0034] Preferably, in step S41, the stirring reaction temperature is 75-85° C., and the stirring reaction time is 44-48 h; the dosage ratio of tetrabromotetrahydroxyperylene, tetrabutylammonium bromide, potassium hydroxide, and ethyl bromide is 2-3 g: 2-3 g: 140-160 mg: 4-5 ml.

[0035] Preferably, in step S4, the 4-pyridinol, K 2 CO 3 , probe precursor 1, and brominated alkane are used in a dosage ratio of 0.6-0.7 g: 0.13-0.14 g: 0.8-1 g: 0.1-0.5 g.

[0036] Preferably, in step S42, the reflux reaction temperature is 75-80° C., and the reaction time is 20-24 h.

[0037] Preferably, in step S43, the reaction temperature is 80-100° C., and the reaction time is 18-24 h.

[0038] Preferably, the value of n is 6.

[0039] The second aspect of the present invention provides a fluorescent probe prepared by the above preparation method.

[0040] The third aspect of the present invention provides the use of the above fluorescent probe in detecting perchlorate in water.

[0041] The present invention has the following beneficial effects:

[0042] The detection method of the present invention has the characteristics of wide detection linear range, low detection limit, strong anti-interference ability, simple operation, high efficiency and speed, low cost, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 The NMR spectrum of the fluorescent probe prepared in Example 1;

[0045] Figure 2 : (a) is a SEM image of the aggregation state of the fluorescent probe prepared in Example 1 added to the solution; (b) is a SEM image of the aggregation state after the fluorescent probe and perchlorate are added to the solution at the same time;

[0046] Figure 3 :(a) is a SEM image of the aggregation state (obtaining aggregates) after the fluorescent probe prepared in Example 1 and perchlorate are added to the solution at the same time; (b) is a mapping image of the Cl element of the aggregates;

[0047] Figure 4 :(a) Fluorescence intensity curve of the fluorescent probe prepared in Example 1 in solutions with different water contents; (b) Fluorescence intensity peak results of the fluorescent probe in solutions with different water contents;

[0048] Figure 5 This is a comparison result diagram of LOD and sensitivity of fluorescent probes with different carbon chain lengths prepared in Examples 1-9;

[0049] Figure 6 Molecular simulation results of fluorescent probes with different carbon chain lengths: (i) simulation results of fluorescent probes with different carbon chain lengths in the absence of perchlorate; (ii) simulation results of fluorescent probes with different carbon chain lengths in the presence of perchlorate;

[0050] Figure 7 The contact angle results of fluorescent probes with different carbon chain lengths prepared in Examples 1-9;

[0051] Figure 8 Schematic diagram of the binding between the fluorescent probe and perchlorate;

[0052] Fig. 9 The fluorescence intensity diagram of the fluorescent probe prepared in Example 1 for detecting different concentrations of perchlorate;

[0053] Fig.10: (a) Fluorescence peak intensity diagram of the fluorescent probe prepared in Example 1 at different perchlorate concentrations; (b) Linear fitting curve diagram of the fluorescence intensity of the fluorescent probe prepared in Example 1 at different perchlorate concentrations;

[0054] Fig.11 This is a graph showing the selectivity of the fluorescent probe prepared in Example 1 for perchlorate detection;

[0055] Fig.12 This is a stability diagram of the fluorescent probe prepared in Example 1 for perchlorate detection;

[0056] Fig.13 is the chemical structural formula of the fluorescent probe prepared in Example 1. DETAILED DESCRIPTION

[0057] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0058] Example 1

[0059] A method for preparing a fluorescent probe for detecting perchlorate in water comprises the following steps:

[0060] S1. Synthesis of 3,6-dibromo-2,7-dihydroxynaphthalene:

[0061] First, add 8g of 2,7-dihydroxynaphthalene to a round-bottomed double-necked flask and dissolve it in 80mL of acetic acid. Then slowly drop 10mL of bromine in acetic acid solution into the system, and then slowly drop 15mL of water. During the process of adding water, some white precipitates will precipitate. Stir and react at 90°C for 3h. After the solid is completely dissolved, add 8g of tin powder, continue heating and stirring for 12h, and monitor the reaction by TLC. After the reaction is completed, add 90ml of water to quench the reaction, filter to obtain an off-white solid, repeatedly wash with clean water to remove the residual acid, and dry the filtered solid in a vacuum oven at 60°C for 12h. The dried crude product is purified by silica gel flash chromatography column (eluent is petroleum ether: ethyl acetate = 3:1) to obtain a white solid, namely 3,6-dibromo-2,7-dihydroxynaphthalene.

[0062] S2. Synthesis of tetrabromoperylenequinone:

[0063] 2.4 g of 2,7-dibromo-3,6-dihydroxynaphthalene was dissolved in a mixed solution of methanol and water, and then 0.05 M K MnO 4The solution (0.36 g) was slowly added dropwise to the above reaction solution, and the reaction was stirred at room temperature for 36 hours. After the reaction was completed, 2M HCl solution was added dropwise to the reaction solution to adjust the reaction solution to acidity (pH = 2), and the reaction solution was allowed to stand for 1 hour to precipitate a solid precipitate. The solid precipitate was filtered and repeatedly washed with clean water, and then vacuum dried at 55 ° C for 12 hours to obtain the product, which is tetrabromoperylenequinone;

[0064] S3. Synthesis of tetrabromotetrahydroxyperylene:

[0065] Dissolve 2.2 g of tetrabromoperylenequinone in 200 ml of methanol, slowly add 2.5 g of saturated sodium dithionite solution in an argon atmosphere, and stir at room temperature for 20 hours. After the reaction is completed, add 2M HCl solution to the reaction solution, adjust the reaction solution to acidity (pH = 2), let it stand for about 2 hours, and a solid precipitate will precipitate. Filter the solid precipitate and wash it repeatedly with clean water, and vacuum dry it at 55°C for 12 hours to obtain tetrabromotetrahydroxyperylene;

[0066] S4. Generation of fluorescent probes:

[0067] S41. In a double-necked round-bottom flask, add 2.2 g of tetrabromotetrahydroxyperylene, 2.4 g of tetrabutylammonium bromide, and 150 mg of potassium hydroxide, and then add dry 1,4-dioxane solution to dissolve it; 2 Under the atmosphere, 5 ml of ethyl bromide was added, the temperature was raised to 80°, and the reaction was stirred for 46 h. After the reaction was completed, the mixture was extracted with water and dichloromethane, the organic phase was separated, and the mixture was washed with anhydrous MgSO 4 After drying and filtration, the solvent was removed under reduced pressure at 65°C to obtain the probe precursor 1;

[0068] S42, 0.6 g of 4-pyridinol and 0.14 g of K 2 CO 3 The mixture was stirred at room temperature in N-methylpyrrolidone (NMP). 2 11 g of the probe precursor was added, and the mixture was heated to reflux at 75°C for 24 h. After cooling to room temperature, the reaction mixture was poured into 1M HCl, the precipitate was filtered, washed with water until neutral, dried in vacuo at 75°C, and purified by column chromatography (SiO 2 , chloroform / ethyl acetate) to separate and obtain the probe precursor 2;

[0069] S43, 0.8 g of the probe precursor 2 and Br-C 6 H 13 Dissolve in 50 mL of DMF and react at 90 °C for 24 h. Then add excess water to the solution to obtain a precipitate. Filter and obtain a fluorescent probe. Its chemical structure is shown in Fig.13 .

[0070] Example 2

[0071] The same as Example 1, except that in step S4, the bromoalkane is Br-CH 3 .

[0072] Example 3

[0073] The same as Example 1, except that in step S4, the bromoalkane is Br-C 2 H 5 .

[0074] Example 4

[0075] The same as Example 1, except that in step S4, the bromoalkane is Br-C 3 H 7 .

[0076] Example 5

[0077] The same as Example 1, except that in step S4, the bromoalkane is Br-C 4 H 9 .

[0078] Example 6

[0079] The same as Example 1, except that in step S4, the bromoalkane is Br-C 5 H 11 .

[0080] Example 7

[0081] The same as Example 1, except that in step S4, the bromoalkane is Br-C 7 H 15 .

[0082] Example 8

[0083] The same as Example 1, except that in step S4, the bromoalkane is Br-C 8 H 17 .

[0084] Example 9

[0085] The same as Example 1, except that in step S4, the bromoalkane is Br-C 9 H 19 .

[0086] 1. Characterization of materials

[0087] (1) NMR characterization:

[0088] The fluorescent probe with a C6 carbon chain prepared in Example 1 was characterized. 1H NMR results are shown in Figure 1 ,Depend on Figure 1 As a result, hydrogen peaks at different positions can be observed, which proves the successful synthesis of the fluorescent probe.

[0089] (2) Morphological and structural characterization

[0090] The aggregation state (aggregate) of the fluorescent probe prepared in Example 1 and the aggregation state after the fluorescent probe and perchlorate were added to the solution at the same time (aggregate) were tested by SEM. The results are shown in Figure 2 .

[0091] Depend on Figure 2 (a) and Figure 2 (b) The results show that when perchlorate is not added, the size of the aggregate is about 1uM. After the addition of perchlorate, the size of the aggregate increases to 3-4μM because perchlorate promotes the aggregation of the fluorescent probe. This indicates that the addition of perchlorate can promote the aggregation of the fluorescent probe, thereby leading to an increase in the fluorescence intensity.

[0092] (3) The aggregates obtained by adding the fluorescent probe to the perchlorate solution were characterized by ESD. The results are as follows Figure 3 .

[0093] Depend on Figure 3 From the results of (a) and 3(b), we can see that the chlorine element is densely distributed in the aggregates, proving that perchlorate is one of the reasons for the formation of aggregates.

[0094] 2. Fluorescence properties of fluorescent probes in solutions with different water contents (DMF and water mixed in different proportions) are shown in Figure 4 .

[0095] Depend on Figure 4 (a) and Figure 4 (b) The results show that as the proportion of the poor solvent DMF in the solution increases, the corresponding fluorescence intensity also increases significantly, and there is a jump at 60%, which is a typical property of an AIE probe, indicating that the fluorescent probe prepared by the present invention has an obvious AIE effect.

[0096] 3. Effect of fluorescent probes with different carbon chain lengths on the sensitivity of perchlorate detection

[0097] (1) A probe solution was prepared by dissolving 20 μmol / L of the probe molecules (C1-C9) with different carbon chain lengths prepared in Examples 1-9 in a 30% DMF solution. 2 ml of the probe solution was placed in a cuvette, and 20 μL of the sample solution to be tested was added to the cuvette. After mixing well and standing for 2 minutes, the fluorescence intensity of the solution was detected by a fluorescence spectrophotometer. The results are shown in FIG. Figure 5 .

[0098] Depend on Figure 5 The results show that when the carbon chain is C6, the detection limit is the lowest and the sensitivity is the highest, which indicates that the fluorescent probe with a carbon chain of C6 has the best detection effect for perchlorate.

[0099] (2) Simulating the aggregation state of fluorescent probes with different carbon chain lengths (C1-C6) in solutions containing perchlorate and in solutions without perchlorate. The results are shown in Figure 6 .

[0100] Depend on Figure 6 The results of (i) and (ii) show that after adding perchlorate for simulation, the aggregation of the fluorescent probe becomes very obvious. At the same time, the aggregation effect of the fluorescent probe is the best when the carbon chain length is C6, and the aggregation is the most compact. At the same time, it can be found that as the carbon chain length increases, the hydrophobicity of the corresponding fluorescent probe aggregation is enhanced, driving the fluorescent probe to assemble and aggregate. The effect is strongest when the carbon chain length is C6. After the carbon chain length continues to increase, the overly long carbon chain hinders the tight binding of the fluorescent probe.

[0101] (3) Contact angle test of fluorescent probes with different carbon chain lengths

[0102] like Figure 7 As shown, by characterizing the contact angles of probe molecules with different carbon chain lengths, the size of the contact angle can reflect the hydrophobicity of the probe solution. Figure 7 The results show that as the length of the carbon chain increases, the hydrophobicity of the probe solution also increases, which represents the improvement of the hydrophobic effect of the probe. Combined with the changes in the detection performance of different carbon chain probe molecules for perchlorate, we believe that the size of the hydrophobic effect is an important reason for changing the detection performance of the probe for perchlorate. The matching of perchlorate and the appropriate hydrophilic and hydrophobic probe is the key to improving the detection performance. The appropriate hydrophilic and hydrophobic matching can greatly improve the selectivity of the probe detection, thereby improving the detection performance. In summary, the probe provides attraction to perchlorate through the positively charged pyridine N, and adjusts the appropriate hydrophobic effect by controlling the carbon chain length to provide superior selectivity for perchlorate.

[0103] In summary, the electrostatic interaction between the positively charged pyridine N and the negatively charged pyridine and the hydrophobic effect brought by the carbon chain are the key to achieving perchlorate fluorescence sensing. Figure 8 As shown, the probe adsorbs perchlorate through electrostatic and hydrophobic interactions. Perchlorate acts as an intermediate to bridge adjacent probes and promote the aggregation of probes. The aggregation of probes will lead to the weakening of the vibration of the perylene core skeleton in the probe, and more energy can be dissipated in the form of light, resulting in the generation of fluorescence. As the concentration of perchlorate increases, the aggregation of aggregates also increases, resulting in an increase in fluorescence intensity. The detection of perchlorate concentration is achieved by detecting the fluorescence intensity.

[0104] 4. Analytical performance of fluorescent probes

[0105] Different concentration gradients (0 μM to 13 mM) of perchlorate were added to the fluorescent probe solution, and the fluorescence intensity at different wavelengths was detected. The results are shown in Fig. 9 .

[0106] Depend on Fig. 9 The results show that as the concentration of perchlorate increases, the fluorescence intensity of the solution also increases. Figure 8 According to the analysis, this may be the result of perchlorate promoting the aggregation of fluorescent probes.

[0107] 5. Linear performance of the fluorescent probe for perchlorate.

[0108] Different concentration gradients (0 μM to 13 mM) of perchlorate were added to the fluorescent probe solution for fluorescence detection. The test results are as follows: Fig.10 shown.

[0109] Depend on Fig.10 (a) The results show that the fluorescence intensity of the fluorescent probe increases with the increase of perchlorate concentration.

[0110] The fluorescence intensity of the signal response under different concentration gradients is compared with the corresponding perchlorate (ClO 4 - ) concentrations and obtain a linear fitting curve, such as Fig.10 shown.

[0111] Depend on Fig.10 (b) The results show that the fluorescence peak intensity changes linearly with the perchlorate concentration, and the linear fitting curve equation is y=2026.9x+2512.5, R 2 =0.996, indicating that the linear fitting curve has a good fitting degree, and the fluorescence intensity and concentration show a good linear relationship in the range of 0.5μM to 11μM. After calculation, the lowest detection limit (LOD) is 6.37nM (0.63μg / L). The above results show that the fluorescent probe prepared by the present invention has a wide linear range and a low detection limit.

[0112] 6. Selectivity of fluorescent probes

[0113] Since various interfering substances may exist in the water body detection process, which may affect the detection results, 5 equivalents of Br - , NO 3 - , NO 2 - , H 2 PO 4 -, HCO 3 , HSO 3 - , CH 3 COO - , CO 3 2- , SO 4 2- , Cl - , ClO - , ClO 2 - , ClO 3 - , I - , SCN - As interfering substances and ClO 4 - Add to the fluorescent probe solution and detect the change in fluorescence intensity before and after adding interfering ions. Fig.11 .

[0114] Depend on Fig.11 The results show that only ClO 4 - The addition of will cause a dramatic fluorescence change of the fluorescent probe. This indicates that the fluorescent probe prepared by the present invention has excellent selectivity for perchlorate.

[0115] 7. Stability of fluorescent probe for perchlorate detection

[0116] To study the reproducibility of the fluorescent probe, the fluorescent probe was added to a perchlorate solution for detection and then placed at room temperature for 30 days. The detection was repeated under the same conditions after 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 days, respectively. The results are shown in Figure 2. Fig.12 shown.

[0117] Depend on Fig.12 The results show that the fluorescent probe prepared in Example 1 can be used to detect perchlorate within 30 days, and the results show that the fluorescent probe can be stored for a long time, and the detection effect of perchlorate will not be affected during long-term storage. The results prove that the fluorescent probe has good stability.

[0118] 8. Detection and analysis of perchlorate in actual water samples

[0119] In order to investigate the practical application performance of the fluorescent probe, tap water and Xiangjiang River water (diluted 1000 times) were selected for testing, and the fluorescent probe prepared in Example 1 was used for the quantitative determination of perchlorate in actual water samples (tap water and Xiangjiang River water) and the spike recovery test. The above water samples were filtered through a 0.22 μM filter membrane to remove solid impurities and flocculation precipitation in the water samples. The test results are shown in Table 1 below.

[0120] Table 1

[0121]

[0122] From the results in Table 1, it can be seen that after experiments, the recovery rate of the fluorescent probe in actual water bodies is between 96.9% and 101%. After repeated tests, the RSD of the test results is below 4%, indicating that the fluorescent probe effect is stable, which means that the modified click is feasible for detecting perchlorate in actual water samples, and has good reproducibility and great application potential.

[0123] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.

Claims

1. A method for preparing a fluorescent probe for detecting perchlorate in water, characterized in that: The following steps are involved: S1. Synthesis of 3,6-dibromo-2,7-dihydroxynaphthalene: The acetic acid solution of 2,7-dihydroxynaphthalene, the acetic acid solution of liquid bromine and water are mixed, stirred for reaction, tin powder is added after all the solid is dissolved, the stirring for reaction is continued, water is added to quench the reaction after the reaction is completed, the reaction is filtered, washed, dried, and purified by silica gel flash chromatography column to obtain 3,6-dibromo-2,7-dihydroxynaphthalene; S2. Synthesis of tetrabromoperylenequinone: Dissolve 2,7-dibromo-3,6-dihydroxynaphthalene in a mixed solution of methanol and water, then add KMnO4 solution, stir and react at room temperature, after the reaction is completed, add HCl solution to the reaction solution, adjust the reaction solution to acidity, let it stand, precipitate solid precipitate, filter the solid precipitate, repeatedly wash it with clean water, and vacuum dry it to obtain tetrabromoperylenequinone; S3. Synthesis of tetrabromotetrahydroxyperylene: Dissolve tetrabromoperylenequinone in methanol, add saturated sodium dithionite solution in an argon atmosphere, and react by stirring at room temperature. After the reaction is completed, add HCl solution dropwise to the reaction solution to adjust the reaction solution to acidity, let it stand, precipitate solid, filter the solid precipitate, wash it repeatedly with clean water, and dry it in vacuum to obtain tetrabromotetrahydroxyperylene; S4. Synthesis of fluorescent probe: S41, adding tetrabromotetrahydroxyperylene, tetrabutylammonium bromide and potassium hydroxide to a dry 1,4-dioxane solution and dissolving them, adding ethyl bromide under a N2 atmosphere, stirring to react, and after the reaction is completed, extracting with water and dichloromethane, separating the organic phase and drying it with anhydrous MgSO4, filtering it with suction, and removing the solvent under reduced pressure to obtain a probe precursor 1; S42, dissolving 4-pyridinol and K2CO3 in N-methylpyrrolidone under stirring at room temperature, adding probe precursor 1 under N2, reflux reaction, cooling to room temperature, pouring the reaction mixture into HCl, filtering the precipitate, washing with water until neutral, vacuum drying, and purifying by column chromatography to separate and obtain probe precursor 2; S43, dissolving the obtained probe precursor 2 and bromoalkane in DMF, wherein the chemical formula of bromoalkane is Br-C n H 2n+1 , where n is 1 to 9, and the reaction is allowed to proceed. After the reaction is completed, excess water is added and the reaction is filtered to obtain a fluorescent probe.

2. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: In step S1, the dosage ratio of the 2,7-dihydroxynaphthalene, liquid bromine, water and tin powder is 8-10 g: 8-11 mL: 12-15 mL: 6-8 g; the reaction temperature is 80-100° C., the reaction time is 2-3 h; and the stirring reaction time is 10-12 h.

3. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: In step S2, the concentration of the KMnO4 solution is 0.02~0.05M, and the dosage ratio of the 2,7-dibromo-3,6-dihydroxynaphthalene and KMnO4 solution is 2~3g:0.3g~0.4g; the room temperature stirring reaction time is 34~36h, and the standing time is 1~2h.

4. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: In step S3, the dosage ratio of tetrabromoperylenequinone to saturated sodium dithionite solution is 2-3 g: 2.2-3.2 g.

5. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: In step S3, the stirring reaction time at room temperature is 20-24 hours, the standing time is 1-3 hours, the vacuum drying temperature is 50-60° C., and the drying time is 10-12 hours.

6. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: In step S41, the stirring reaction temperature is 75-85°C, and the stirring reaction time is 44-48h; the dosage ratio of tetrabromotetrahydroxyperylene, tetrabutylammonium bromide, potassium hydroxide, and ethyl bromide is 2-3g: 2-3g: 140-160mg: 4-5ml.

7. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: The dosage ratio of the 4-pyridinol, K2CO3, probe precursor 1 and bromoalkane is 0.6~0.7g: 0.13~0.14g: 0.8~1g: 0.1~0.5g; in step S42, the reflux reaction temperature is 75~80°C, and the reaction time is 20~24h; in step S43, the placement reaction temperature is 80~100°C, and the reaction time is 18~24h.

8. The method for preparing a fluorescent probe for detecting perchlorate in water according to claim 1, characterized in that: The value of n is 6.

9. A fluorescent probe for detecting perchlorate in water, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7, wherein n≠6.

10. Use of the fluorescent probe as claimed in claim 9 in detecting perchlorate in water.

Images