Preparation method and application of a pyridylhydrazone multifunctional fluorescent probe

Abstract

A preparation method and application of a pyridylhydrazone multifunctional fluorescent probe relates to the field of analysis and detection, and in particular to a preparation method of a pyridylhydrazone fluorescent probe and multi-response identification of zinc ions, aluminum ions, glyphosate and fluoride ions, which can solve the deficiency that existing fluorescent probes cannot simultaneously respond to multiple cations and anions under the same test conditions. The preparation method of the fluorescent probe L in the present invention is: 2-methylthio-3-pyridinecarboxylic acid hydrazide and 2-hydroxy-1-naphthaldehyde are condensed under liquid phase conditions to prepare it. The fluorescent probe prepared by the present invention can realize the wavelength and intensity differential response identification of zinc ions and aluminum ions under the action of 446nm excitation light, and the complex L-Zn 2+ 、L‑Al 3+ The fluorescent probe prepared by the present invention has the advantages of strong specificity, high sensitivity and naked eye recognition during use, and can be used for differential fluorescence detection of multiple ions in complex environments.

Description

Technical Field

[0001] The present invention relates to the field of multi-ion detection, and in particular to a preparation method of a pyridylhydrazone derivative and application of the pyridylhydrazone derivative in multi-response identification of zinc ions, aluminum ions, glyphosate and fluoride ions. Background Art

[0002] Rapid industrial development has led to increasingly serious environmental pollution. Excessive cations, anions, and pesticides in the environment pose a serious threat to human health. For example, an imbalance in zinc ion levels in the body can lead to neuronal dysfunction, inducing diseases such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and Creutzfeldt-Jakob disease. Excessive aluminum ion intake can be toxic, causing various diseases such as Alzheimer's, Parkinson's, osteoporosis, and breast cancer. Fluoride, an essential component of teeth and bones, can cause fluorosis, kidney, gastrointestinal, and immune toxicity, leading to immune damage and even death when fluoride ion concentrations in the body are too high. Excessive intake of the pesticide glyphosate can harm the central nervous system, causing respiratory, myocardial, and neurological dysfunction, and even cancer. Therefore, dynamic detection of multiple harmful ions in the environment is crucial.

[0003] While traditional ion detection methods, such as chromatography and mass spectrometry, can meet this need to a certain extent, they often require complex sample pretreatment and analysis steps, are time-consuming, and require specialized equipment and operators, limiting their application in rapid on-site testing and large-scale sample analysis. Fluorescent probe detection, on the other hand, is widely used in the detection of various substances due to its advantages such as ease of operation, high sensitivity, good selectivity, real-time monitoring, visualization, and on-site detection.

[0004] Pyridine is a nitrogen-containing six-membered heterocyclic compound with more stable chemical properties than benzene. The nitrogen atom on the pyridine ring has a pair of unshared electrons, which enables it to form complexes with a variety of Lewis acids. Pyridoylhydrazone is a class of derivatives prepared by the condensation reaction of pyridoylhydrazide and aldehyde. The C=N bond in the Schiff base structure is a commonly used coordination chemical ligand, and pyridoylhydrazone derivatives can provide more complexation sites because they have both C=N and C=O bonds. At the same time, pyridoylhydrazone derivatives also have excellent fluorescence properties. Therefore, they have attracted much attention in the field of fluorescent material preparation. The present invention designs and prepares a novel pyridoylhydrazone fluorescent probe that can achieve differential responses to four ions: zinc ions, aluminum ions, glyphosate and fluoride ions under the same test conditions. The response process has the advantages of simple operation, good specificity, high sensitivity, and can be identified by the naked eye. Summary of the Invention

[0005] The present invention aims to solve the deficiency that existing fluorescent probes cannot respond to multiple cations and anions simultaneously and differentially under the same test conditions, and provides a preparation method and application of a four-response multifunctional fluorescent probe.

[0006] The present invention provides a pyridylhydrazone multifunctional fluorescent probe L, wherein the molecular structure of L is:

[0007]

[0008] The synthetic route of the fluorescent probe L is as follows:

[0009]

[0010] The preparation method of the probe L is as follows: 2-methylthio-3-pyridinecarboxylic acid hydrazide and 2-hydroxy-1-naphthaldehyde are condensed under liquid phase conditions.

[0011] The present invention utilizes the application of pyridylhydrazone fluorescent probe L in the multi-response detection of zinc ions, aluminum ions, glyphosate and fluoride ions.

[0012] Preferably, at an excitation wavelength of 446 nm, the fluorescence of the probe L at 514 nm is enhanced 10 times after recognizing zinc ions, and is quenched after adding glyphosate, with a quenching rate of 89%.

[0013] Preferably, at an excitation wavelength of 446 nm, the fluorescence of the probe L at 497 nm is enhanced by 71 times after recognizing aluminum ions, and is quenched after adding fluoride ions, with a quenching rate of 82%.

[0014] Furthermore, the detection limit of probe L for aluminum ions was as low as 1.66×10 -8 mol / L.

[0015] Furthermore, the interaction ratio of probe L to aluminum ions is 1:1.

[0016] Furthermore, the complex L-Al 3+ Resistant to P2O7 during fluoride ion detection 4- ,HCO3 - ,Cr2O7 2- ,Cl - ,NO3 - ,Br - ,SO3 2- ,S2O3 2- ,I - ,CH3COO - ,CO3 2- ,SO4 2- ,HSO4 - ,PO4 3- ,NO2 - interference.

[0017] Principle of the present invention:

[0018] The pyridylhydrazone fluorescent probe prepared by the present invention has a planar and large-scale π-conjugated structure. Under the same test conditions, it can form a complex with zinc ions or aluminum ions through carbonyl, phenolic hydroxyl and imine bonds. Due to the different properties of zinc ions and aluminum ions, the coordination reaction leads to different positions and intensities of the fluorescence emission peaks, thereby achieving specific detection of zinc ions and aluminum ions. Glyphosate can remove zinc ions from the complex L-Zn 2+ Similarly, fluoride ions can displace aluminum ions from the complex L-Al 3+ The fluorescent probe is displaced from the monomer state, and the fluorescence effect is restored, thereby realizing the fluorescence detection of glyphosate and fluoride ions.

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

[0020] 1) The pyridylhydrazone derivatives prepared in the present invention can realize the differential detection of multiple cations (zinc ions, aluminum ions) and multiple anions (glyphosate and fluoride ions) under the same test conditions, thereby expanding the application of the probe.

[0021] 2) The fluorescent probe prepared by the present invention has a novel structure, is easy to operate, and has excellent performance, which reduces the synthesis work of the probe and makes the fluorescent probe detection method more energy-saving and green. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Fluorescent probes 1 H NMR spectrum;

[0023] Figure 2 Fluorescent probes are selective in recognizing metal ions;

[0024] Figure 3 Fluorescent probes for Al 3+ Fluorescence response anti-interference;

[0025] Figure 4 Fluorescent probes for different concentrations of Al 3+ Linear relationship diagram of fluorescence response;

[0026] Figure 5 Complex L-Zn 2+ Selective recognition of glyphosate;

[0027] Figure 6 Complex L-Al 3+ Selective recognition of fluoride ions;

[0028] Figure 7 Complex L-Al 3+Recognition of fluoride ions in the presence of different anions;

[0029] Figure 8 Complex L-Al 3+ Linear relationship diagram of fluorescence response to different concentrations of fluoride ions;

[0030] Figure 9 Complex L-Al 3+ Line graph of cyclic detection of aluminum ions and fluoride ions; DETAILED DESCRIPTION

[0031] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0032] Specific embodiment 1: The molecular structure of a pyridylhydrazone multifunctional fluorescent probe L is:

[0033]

[0034] Specific embodiment 2: A method for preparing a pyridoylhydrazone multifunctional fluorescent probe L is as follows: 2-methylthio-3-pyridinecarboxylic acid hydrazide and 2-hydroxy-1-naphthaldehyde are condensed under liquid phase conditions to prepare the probe.

[0035] Specific embodiment three: Application of the fluorescent probe L in this embodiment in the multi-response detection of zinc ions, aluminum ions, glyphosate and fluoride ions.

[0036] Specific embodiment 4: This embodiment differs from specific embodiment 3 in that: at an excitation wavelength of 446 nm, the fluorescence at 514 nm is enhanced 10-fold after the probe recognizes zinc ions, and is quenched by 89% after the addition of glyphosate. Other aspects are the same as specific embodiment 3.

[0037] Specific embodiment 5: This embodiment differs from specific embodiment 3 or 4 in that: at an excitation wavelength of 446 nm, the probe recognizes aluminum ions and exhibits a 71-fold fluorescence enhancement at 497 nm. Addition of fluoride ions quenches the fluorescence, with a quenching rate of 82%. Other aspects are the same as specific embodiment 3 or 4.

[0038] Specific embodiment 6: This embodiment differs from the specific embodiment 5 in that the detection limit of probe L for aluminum ions is as low as 1.66×10 -8 mol / L. Other aspects are the same as those in the fifth embodiment.

[0039] Specific embodiment 7: This embodiment differs from specific embodiment 5 or 6 in that the ratio of the probe L to the aluminum ion is 1:1. Other aspects are the same as specific embodiment 5 or 6.

[0040] Specific embodiment eight: This embodiment differs from specific embodiment five, six or seven in that: the complex L-Al 3+ Resistant to P2O7 during fluoride ion detection 4- ,HCO3 - ,Cr2O7 2- ,Cl - ,NO3 - ,Br - ,SO3 2- ,S2O3 2- ,I - ,CH3COO - ,CO3 2- ,SO4 2- ,HSO4 - ,PO4 3- ,NO2 - The rest is the same as that of the fifth, sixth or seventh embodiment.

[0041] The HEPES buffer solution is used in this embodiment to prevent the pH of the probe solution from changing, and at the same time to verify whether the probe can be used in cell experiments.

[0042] The following embodiments of the present invention are described in detail. The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation plans and specific operating processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0043] Example 1: Preparation of fluorescent probe L, according to the following steps:

[0044] 2-Methylthio-3-pyridinecarboxylic acid hydrazide (0.183 g, 1 mmol) and 2-hydroxy-1-naphthaldehyde (0.172 g, 1 mmol) were added to a 50 mL three-necked flask and refluxed for 6 h. The mixture was cooled to precipitate a light yellow solid, which was filtered, washed, and dried to obtain a pyridoylhydrazone derivative (0.276 g, 0.82 mmol) in a yield of 81.9%. 1 H NMR (300 MHz, DMSO-d6) δ 12.49 (s, 1H), 12.23 (s, 1H), 9.35 (s, 1H), 8.64 (d, J = 3.8 Hz, 1H), 8.28 (d, J = 8.7 Hz, 1H), 8.02 (d, J = 6.6 Hz, 1H), 7.93 (dd, J = 14.0, 8.4 Hz, 2H), 7.61 (t, J = 7.7 Hz, 1H), 7.42 (t, J = 7.6 Hz, 1H), 7.35–7.25 (m, 2H), 2.51 (s, 3H) ppm. 1 H NMR spectrum Figure 1 shown.

[0045] Example 2: The fluorescent probe L in this example selectively recognizes metal ions according to the following steps:

[0046] Take 3mL of fluorescent probe L solution (V DMSO :V 水 =95:5, HEPES 2.5 mM, pH = 7.4) in a cuvette, and 3 eq. of Hg 2+ ,Mg 2+ ,Pb 2+ ,Li + ,Bi 3+ ,Na + ,Cd 2+ ,K + ,Co 3+ ,Fe 3+ ,Ag + ,Cu 2+ ,Ca 2+ ,Ba 2+ ,Cr 3+ ,Cs + ,Al 3+ and Zn 2+ At an excitation wavelength of 446 nm, the fluorescence emission peak was measured and Zn was added. 2+ After that, there is obvious fluorescence at 514nm, and the fluorescence is enhanced 10 times; 3+ After addition, the fluorescence at 497 nm was significantly enhanced, with the fluorescence enhanced by 71 times. However, the addition of other metal ions did not cause significant fluorescence changes. The fluorescence probe was not sensitive to Zn 2+ and Al 3+ Shows specific discrimination, the results are as follows Figure 2 shown.

[0047] Example 3: The anti-interference performance of the fluorescent probe L in this example for aluminum ion detection was carried out according to the following steps:

[0048] Each time, 3 mL was taken with a concentration of 1.0×10 -5 mol / L fluorescent probe solution, and 3eq. of Hg 2+ ,Mg 2+ ,Pb 2+ ,Li + ,Bi 3+ ,Na + ,Cd 2+ ,K + ,Co 3+ ,Fe 3+ ,Ag + ,Cu 2+ ,Ca 2+ ,Ba 2+,Cr 3+ ,Cs + The fluorescence intensity was measured at an excitation wavelength of 446 nm. 3 eq. of Al 3+ The fluorescence intensity was measured again. The results were as follows Figure 3 As shown in the data analysis, when other metal ions exist in the fluorescent probe solution, the fluorescence intensity of the system will not change. 3+ After that, remove Cu 2+ In addition, the fluorescence of the system is significantly enhanced. This shows that probe L has excellent anti-interference ability in the presence of interfering cations and can reliably detect Al 3+ Specific detection.

[0049] Example 4: The detection limit of the fluorescent probe L for aluminum ions in this example was determined by the following steps:

[0050] Take 3mL of the solution with a concentration of 1.0×10 -5 mol / L fluorescent probe solution, 3 μL was added each time with a concentration of 1×10 -3 mol / L aluminum ion aqueous solution, measure the fluorescence intensity. Plot the graph with aluminum ion concentration as the horizontal axis and fluorescence intensity as the vertical axis. The results are as follows Figure 4 As shown in the figure, data analysis shows that when the aluminum ion concentration is within 0-10 μM, the fluorescence intensity increases with the increase of aluminum ion concentration, and the fluorescence intensity and aluminum ion concentration show a good linear relationship. The fitting equation is Y=190.04X+49.75, R 2 =0.997. According to the calculation formula of detection limit 3σ / k, the detection limit of the probe molecule for aluminum ions is calculated to be 1.66×10 -8 mol / L. The probe can realize trace detection of aluminum ions.

[0051] Example 5: Complex L-Zn 2+ For the selective identification of glyphosate, follow the steps below:

[0052] Take 3mL of the solution with a concentration of 1.0×10 -5 mol / L complex L-Zn 2+ The solution was added with 3 eq. of glyphosate, trichlorfon, phosmet, dichlorvos, malathion, omethoate, dimethoate, ethoprophos, fenitrothion, methyl parathion, parathion and glufosinate in sequence, and the fluorescence intensity was measured at an excitation wavelength of 446 nm. The results are as follows. Figure 5 As shown in the data analysis, when glyphosate was added, the fluorescence of the system was significantly quenched, with a quenching rate of 89%. However, when other pesticides were added, the fluorescence intensity did not change significantly. 2+ The system achieves specific recognition of glyphosate.

[0053] Example 6: Complex L-Al 3+ For the selective recognition of fluoride ions, follow these steps:

[0054] Take 3mL of the solution with a concentration of 1.0×10 -5 mol / L complex L-Al 3+ solution, and then add 3eq. of P2O7 4- ,HCO3 - ,Cr2O7 2- ,Cl - ,NO3 - ,Br - ,SO3 2- ,S2O3 2- ,I - ,CH3COO - ,CO3 2- ,SO4 2- ,HSO4 - ,F - ,PO4 3- ,NO2 - The fluorescence intensity of the solution was measured at an excitation wavelength of 446 nm. Figure 6 From the data analysis, it is found that when fluoride ions are added, the fluorescence of the system is significantly quenched, with a quenching rate of 82%. However, when other common anions are added, the fluorescence intensity does not change significantly. 3+ Specific recognition of fluoride ions was achieved.

[0055] Example 7: Complex L-Al 3+ To identify the fluoride ion interference resistance, follow these steps:

[0056] At a concentration of 1.0×10 -5 mol / L complex L-Al 3+ 3eq. of P2O7 were added to the solution 4- ,HCO3 - ,Cr2O7 2- ,Cl - ,NO3 - ,Br - ,SO3 2- ,S2O3 2- ,I - ,CH3COO - ,CO3 2- ,SO4 2- ,HSO4 - ,PO4 3- ,NO2 - Then, 3eq. of fluoride ions were added in sequence, and the changes in fluorescence intensity were observed and recorded. The results are as follows Figure 7 From the data analysis, it can be seen that in the presence of other coexisting anions, fluorescence quenching can still be achieved after adding fluoride ions. Other anions have a great influence on the complex L-Al 3+ The system recognizes fluoride ions without interference.

[0057] Example 8: Complex L-Al 3+ For the fluoride ion detection limit, follow the steps below:

[0058] In the complex L-Al 3+ 4.5 μL of the solution was added each time to a concentration of 1×10 -3 mol / L fluoride ion aqueous solution, measure the fluorescence intensity, the result is as follows Figure 8 As shown in the figure, data analysis shows that when the fluoride ion concentration is within 0-30 μM, the fluorescence intensity decreases with the increase of fluoride ion concentration, and the fluorescence intensity and fluoride ion concentration show a good linear relationship. The fitting equation is Y = -124.55X + 2152.82, R 2 =0.994. According to the calculation formula of detection limit 3σ / k, the complex L-Al 3+ The detection limit for fluoride ions is 2.75×10 -7 mol / L. Complex L-Al 3+ The system can realize trace detection of fluoride ions.

[0059] Example 9: Fluorescent probe L cyclic recognition of aluminum ions and fluoride ions performance test, according to the following steps:

[0060] At a concentration of 1.0×10 -5 mol / L probe solution was added with 1eq. of aluminum ion solution, and the fluorescence emission peak intensity at 497nm was measured under the excitation wavelength of 446nm. Then 3eq. of fluoride ion aqueous solution was added, and the fluorescence emission peak intensity at 497nm was measured under the excitation wavelength of 446nm. The above operation was repeated 5 times, and the fluorescence curve of the probe L cyclic recognition of aluminum ion and fluoride ion was plotted. The results are shown in the figure. Figure 9 As shown in the figure, the cycling experiment results show that probe L can achieve fluorescence "off-on-off" relay recognition of aluminum and fluoride ions with stable performance, with no significant change in fluorescence intensity after more than five cycles of detection. This demonstrates that the detection method exhibits good reproducibility and shows potential for practical application.

Claims

1. Application of a fluorescent probe L in the preparation of a multi-response detection reagent for detecting zinc ions, aluminum ions, glyphosate and fluoride ions, characterized in that The molecular structure of the fluorescent probe L is:

2. The use according to claim 1, characterized in that At an excitation wavelength of 446 nm, the fluorescence of probe L at 514 nm increased 10 times after recognizing zinc ions, and was quenched by glyphosate, with a quenching rate of 89%.

3. The use according to claim 1, characterized in that At an excitation wavelength of 446 nm, the fluorescence of probe L at 497 nm was enhanced by 71 times after recognizing aluminum ions, and the fluorescence was quenched after adding fluoride ions, with a quenching rate of 82%.

4. The use according to claim 3, characterized in that The detection limit of probe L for aluminum ions is as low as 1.66×10 - 8 mol / L.

5. The use according to claim 3, characterized in that Complex L-Al 3+ Resistant to P2O7 during fluoride ion detection 4- ,HCO3 - ,Cr2O7 2- ,Cl - ,NO3 - ,Br - ,SO3 2- ,S2O3 2- ,I - ,CH3COO - ,CO3 2- ,SO4 2- ,HSO4 - ,PO4 3- ,NO2 - interference.

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