Fluorescent probe for detecting zinc ions in water body as well as preparation method and detection method of fluorescent probe

Abstract

The invention discloses a fluorescent probe for detecting zinc ions in a water body and a preparation method and a detection method thereof, the preparation method comprises the following steps: S1, mixing o-phenylenediamine and 2, 6-dialdehyde-1, 5-dihydroxynaphthalene according to a molar ratio, then adding NaOH and ethanol, and carrying out ultrasonic dispersion and stirring reaction under heating to obtain a product solution; s2, centrifugally separating the product solution, collecting a solid product, washing and drying to obtain the fluorescent probe. The preparation method of the fluorescent probe is simple, low in equipment requirement, high in yield and low in cost, and macro preparation can be realized; the probe is stable in luminescence and wide in excitation wavelength, and is particularly suitable for being used as a probe molecule for fluorescence sensing application. The method for detecting Zn < 2 + > in the water environment based on the probe has a wide Zn < 2 + > detection range of 5-150 [mu] M, has the advantages of simple operation, rapidness, high efficiency, good specificity, low detection limit and the like, and has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the fields of fluorescent probe molecule synthesis and chemical sensors, and in particular to a fluorescent probe for detecting zinc ions in water, a preparation method thereof and a detection method thereof. Background Art

[0002] Existing Zn 2+ Detection methods are widely used in fields such as environmental monitoring, industrial wastewater treatment, and biological research, but these methods still have some shortcomings. Zinc ions often coexist with other metal ions (such as copper, nickel, and lead) in environmental samples. Traditional detection methods, such as colorimetry and electrochemical methods, generally lack sufficient selectivity and are easily interfered with by other ions, resulting in inaccurate results. In addition, some detection methods, especially traditional spectroscopic methods (such as atomic absorption spectrometry), require complex pretreatment steps such as sample concentration and filtration, which increases the difficulty and time cost of operation. For on-site monitoring, such methods are not convenient and efficient. Some precise zinc ion detection methods, such as inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS), rely on expensive and bulky instrumentation, making them unsuitable for on-site detection and requiring high maintenance costs. Therefore, the development of new and efficient zinc ion detection technologies to overcome the shortcomings of existing methods remains an important direction for future research. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a fluorescent probe for detecting zinc ions in water, a preparation method thereof and a detection method thereof in view of the deficiencies in the above-mentioned prior art. The present invention proposes a method for efficiently preparing organic fluorescent probe molecules, which can solve the problems of few existing preparation methods, complicated procedures and high costs, and realize efficient and large-scale preparation of fluorescent probes. In this method, o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene are selected as raw materials, ethanol is used as solvent, and a fluorescent probe is prepared under a heating environment. The fluorescent probe has the characteristics of a wide excitation wavelength, and 320-600nm excitation can achieve fluorescence emission at 624nm; when Zn is added 2+ Afterwards, Zn 2+ The coordination reaction with the fluorescent probe causes the electron cloud distribution in the fluorescent molecule to change, causing the energy level of the electron transition to change, which in turn causes the emission wavelength of the fluorescence to blue shift (i.e., the wavelength becomes shorter); at the same time, the fluorescence state of the molecule becomes more stable after coordination, thereby increasing the quantum yield of fluorescence, which is manifested as fluorescence enhancement. According to the change of fluorescence intensity at 572nm, Zn in water environment can be realized. 2+ Qualitative and quantitative detection.

[0004] To achieve the above object, the technical solution adopted by the present invention is: In a first aspect of the present invention, a method for preparing a fluorescent probe for detecting zinc ions in water is provided, comprising the following steps:

[0005] S1, o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were mixed by mole, and then NaOH and ethanol were added, ultrasonically dispersed, and stirred under heating to react to obtain a product solution;

[0006] S2. Centrifuge the product solution, collect the solid product, wash and dry it to obtain the fluorescent probe.

[0007] Preferably, in step S1, the molar ratio of o-phenylenediamine to 2,6-dialdehyde-1,5-dihydroxynaphthalene is 0.5 to 2:1.

[0008] Preferably, in step S1, the reaction temperature is 90-110° C., and the reaction time is 3-12 h.

[0009] Preferably, in step S1, the ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.001-0.1.

[0010] Preferably, in step S1, the volume ratio of the sum of the masses of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:20 to 80, measured in g by mass and mL by volume.

[0011] Preferably, the method for preparing the fluorescent probe for detecting zinc ions in water comprises the following steps:

[0012] S1. Mix o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene in a molar ratio of 0.5 to 2:1 in a container, then add NaOH and ethanol, ultrasonically disperse for 15 to 60 minutes, and stir at 90 to 110° C. for 3 to 12 hours to obtain a product solution;

[0013] S2. Centrifuge the product solution to collect the solid product, wash it with ethanol 1-6 times, and then vacuum dry it at 50-90° C. for 12-36 hours to obtain the fluorescent probe.

[0014] Preferably, the method for preparing the fluorescent probe for detecting zinc ions in water comprises the following steps:

[0015] S1. o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were mixed in a container at a molar ratio of 1:1, and then NaOH and ethanol were added. The mixture was ultrasonically dispersed for 30 minutes and stirred at 100° C. for 6 hours to obtain a product solution.

[0016] The ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.01; the volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:50, measured in g and mL.

[0017] S2. The product solution was centrifuged to collect the solid product, which was washed with ethanol three times and then vacuum-dried at 60° C. for 24 h to obtain the fluorescent probe.

[0018] In a second aspect of the present invention, a fluorescent probe for detecting zinc ions in water is provided, which is prepared by the method described above.

[0019] A third aspect of the present invention provides a method for detecting zinc ions in water, comprising the following steps:

[0020] 1) dispersing the fluorescent probe according to claim 8 in ethanol to prepare a probe solution, and measuring the fluorescence intensity of the probe solution at 572 nm under 320-600 nm excitation light, which is recorded as F0;

[0021] 2) The probe solution was mixed with zinc ion standard solutions of different concentrations and reacted for 2-10 minutes. The fluorescence intensity of the resulting product was measured at 572 nm under excitation light of 320-600 nm, recorded as F. A standard curve was constructed based on the different zinc ion concentrations and the corresponding F / F0 values;

[0022] 3) Monitor the fluorescence intensity of a solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 572 nm under excitation light of 320-600 nm, record it as F', calculate the value of F' / F0, and use a pre-constructed standard curve to calculate the zinc ion concentration in the sample to be tested.

[0023] Preferably, the method for detecting zinc ions in water comprises the following steps:

[0024] 1) dispersing the fluorescent probe according to claim 8 in ethanol to prepare a probe solution, and measuring the fluorescence intensity of the probe solution at 572 nm under 460 nm excitation light, which is recorded as F0;

[0025] 2) The probe solution was mixed with zinc ion standard solutions of different concentrations and reacted for 5 minutes. The fluorescence intensity of the resulting product at 572 nm under 460 nm excitation light was measured, recorded as F. A standard curve was constructed based on different zinc ion concentrations and the corresponding F / F0 values;

[0026] 3) Monitor the fluorescence intensity of a solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 572 nm under excitation light of 460 nm, record it as F', calculate the value of F' / F0, and use the pre-constructed standard curve to calculate the zinc ion concentration in the sample to be tested.

[0027] The beneficial effects of the present invention are:

[0028] (1) The present invention uses o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene as raw materials, ethanol as solvent, and NaOH as auxiliary agent to prepare a fluorescent probe through Schiff base reaction. The probe reacts with Zn 2+ After coordination, the electron cloud distribution in the fluorescent molecule changes, resulting in a blue shift in fluorescence, which is manifested as enhanced fluorescence at 572nm. Therefore, the change in fluorescence intensity at 572nm can be used to realize the Zn 2+ Qualitative and quantitative detection;

[0029] (2) The preparation method of the fluorescent probe in the present invention is simple, has low equipment requirements, high yield, low cost, and can be prepared in large quantities; in addition, the probe has stable luminescence and a wide excitation wavelength, making it particularly suitable as a probe molecule for fluorescence sensing applications.

[0030] (3) The present invention provides a method for detecting Zn in water environment based on the probe 2+ The method of Zn 2+ The detection range is wide: 5-150μM, and it has the advantages of simple operation, rapid and efficient, good specificity, and low detection limit, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a graph showing the quantum yield test results of the fluorescent probe prepared in Example 1;

[0032] Figure 2 Graphs showing the emission spectra of the fluorescent probe prepared in Example 1 at different excitation wavelengths;

[0033] Figure 3 The fluorescence intensity changes at 572 nm after the fluorescent probe prepared in Example 1 reacted with different metal ions;

[0034] Figure 4 The fluorescent probe prepared in Example 1 and Zn 2+ Fluorescence spectra after different reaction times;

[0035] Figure 5 The fluorescent probe prepared in Example 1 was mixed with different concentrations of Zn 2+ Fluorescence intensity test results after the reaction;

[0036] Figure 6 This is the standard curve constructed in Example 4. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description.

[0038] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Materials and reagents used in the following examples are commercially available unless otherwise specified. In the following examples, where specific conditions are not specified, the experiments were conducted under conventional conditions or those recommended by the manufacturer. Reagents and instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0040] Example 1

[0041] A fluorescent probe for detecting zinc ions in water, the preparation method of which comprises the following steps:

[0042] S1. O-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were mixed in a beaker at a molar ratio of 1:1, and then NaOH and ethanol were added. The mixture was ultrasonically dispersed for 30 minutes and stirred at 100° C. for 6 hours to obtain a product solution.

[0043] The ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.01; the volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:50, measured in g and mL.

[0044] S2. The product solution was centrifuged to collect the solid product at the bottom, washed with ethanol three times, and then dried in a vacuum drying oven at 60° C. for 24 h to obtain the fluorescent probe.

[0045] Example 2

[0046] A fluorescent probe for detecting zinc ions in water, the preparation method of which comprises the following steps:

[0047] S1. O-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were mixed in a beaker at a molar ratio of 1:0.5, and then NaOH and ethanol were added. The mixture was ultrasonically dispersed for 30 minutes and stirred at 100° C. for 6 hours to obtain a product solution.

[0048] The ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.005; the volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:50, calculated in terms of mass in g and volume in mL.

[0049] S2. The product solution was centrifuged to collect the solid product at the bottom, washed with ethanol three times, and then dried in a vacuum drying oven at 60° C. for 24 h to obtain the fluorescent probe.

[0050] Example 3

[0051] A fluorescent probe for detecting zinc ions in water, the preparation method of which comprises the following steps:

[0052] S1. O-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were mixed in a beaker in a molar ratio of 1:2, and then NaOH and ethanol were added. The mixture was ultrasonically dispersed for 30 minutes and stirred at 100° C. for 6 hours to obtain a product solution.

[0053] The ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.05; the volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:50, measured in g and mL.

[0054] S2. The product solution was centrifuged to collect the solid product at the bottom, washed with ethanol three times, and then dried in a vacuum drying oven at 60° C. for 24 h to obtain the fluorescent probe.

[0055] Example 4

[0056] A method for detecting zinc ions in water comprises the following steps:

[0057] 1) The fluorescent probe prepared in Example 1 was dispersed in ethanol to prepare a probe solution, and the fluorescence intensity of the probe solution at 572 nm under 460 nm excitation light was measured, which was recorded as F0;

[0058] 2) The probe solution was mixed with zinc ion standard solutions of different concentrations and reacted for 5 minutes. The fluorescence intensity of the resulting product at 572 nm under 460 nm excitation light was measured, recorded as F. A standard curve was constructed based on different zinc ion concentrations and the corresponding F / F0 values;

[0059] 3) Monitor the fluorescence intensity of a solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 572 nm under excitation light of 460 nm, record it as F', calculate the value of F' / F0, and use the pre-constructed standard curve to calculate the zinc ion concentration in the sample to be tested.

[0060] The construction method of the standard curve is:

[0061] 1) Prepare a series of Zn 2+ aqueous solution;

[0062] 2) Disperse the probe in ethanol to obtain a concentration of 0.1 mg mL -1 The fluorescence intensity of the probe solution at 572 nm under the excitation light of 460 nm was measured and recorded as F0;

[0063] 3) To each Zn 2+ The same volume of probe solution was added to the aqueous solution, and after mixing for 5 minutes, the fluorescence intensity of the obtained product at 572 nm under 460 nm excitation light was measured, which was recorded as F; the value of F / F0 was used as the vertical coordinate, and the value of Zn 2+ The concentration was used as the horizontal axis for curve fitting to obtain the standard curve.

[0064] Test Case

[0065] 1. Test the quantum yield of the fluorescent probe prepared in Example 1, using barium sulfate as a blank. Figure 1 The test results show that its absolute quantum yield is 5.73%.

[0066] 2. Reference Figure 2 Figure 2 shows the emission spectra of the fluorescent probe prepared in Example 1 at different excitation wavelengths. The spectra show that the probe has an optimal excitation wavelength of 460 nm and an optimal emission peak at 624 nm. As the excitation wavelength changes, the probe's emission peak position remains unchanged, while only the fluorescence intensity varies, demonstrating that the fluorescent probe prepared in this invention is excitation wavelength independent.

[0067] 3. Reference Figure 3 , which shows the change in fluorescence intensity at 572 nm after the fluorescent probe prepared in Example 1 reacts with different metal ions; after different types of metal ions are mixed with the ethanol solution of the fluorescent probe prepared in Example 1, the change in the ratio of the fluorescence intensity at a wavelength of 572 nm to the original intensity (F0, i.e., the fluorescence intensity of the ethanol solution of the fluorescent probe when not mixed with metal ions) is monitored. As can be seen in the figure, Zn 2+ The change of the fluorescence probe to Zn 2+ It has strong specific recognition ability.

[0068] 4. Reference Figure 4 , is the fluorescent probe prepared in Example 1 and Zn 2+ The fluorescence spectra after different reaction times show that the best reaction time is 5 minutes.

[0069] 5. Prepare Zn with different concentrations (0-1000 μM) 2+ The aqueous solution was mixed with the ethanol solution of the fluorescent probe prepared in Example 1 for 5 min, and the fluorescence spectrum under 460 nm excitation light was detected. The results were as follows: Figure 5 As shown, it shows that with the increase of Zn 2+ With the increase of concentration, the fluorescence intensity at 572 nm gradually increased. Figure 6 The standard curve constructed in Example 4 shows a good linear relationship when the final concentration is 1-500 μM. The fitting curve equation is y=-40.26*epx(-X / 161.57)+41.73, and the fitting coefficient R 2 =0.993; where x is Zn 2+ The concentration of , y is F / F0.

[0070] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. 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 specific details.

Claims

1. A method for preparing a fluorescent probe for detecting zinc ions in water, characterized in that: The following steps are involved: S1, o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene are mixed in a molar ratio, and then NaOH and ethanol are added, ultrasonically dispersed, and stirred under heating to react to obtain a product solution; S2. Centrifuge the product solution, collect the solid product, wash and dry it to obtain the fluorescent probe.

2. The method for preparing a fluorescent probe for detecting zinc ions in water according to claim 1, wherein In step S1, the molar ratio of o-phenylenediamine to 2,6-dialdehyde-1,5-dihydroxynaphthalene is 0.5 to 2:

1.

3. The method for preparing a fluorescent probe for detecting zinc ions in water according to claim 1, wherein In step S1, the reaction temperature is 90-110° C., and the reaction time is 3-12 h.

4. The method for preparing a fluorescent probe for detecting zinc ions in water according to claim 1, wherein In step S1, the ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.001-0.

1.

5. The method for preparing a fluorescent probe for detecting zinc ions in water according to claim 1, wherein In step S1, the volume ratio of the sum of the masses of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:20 to 80, with the mass unit being g and the volume unit being mL.

6. The method for preparing a fluorescent probe for detecting zinc ions in water according to claim 1, wherein The following steps are involved: S1. Mix o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene in a molar ratio of 0.5 to 2:1 in a container, then add NaOH and ethanol, ultrasonically disperse for 15 to 60 minutes, and stir at 90 to 110° C. for 3 to 12 hours to obtain a product solution; S2. Centrifuge the product solution to collect the solid product, wash it with ethanol 1-6 times, and then vacuum dry it at 50-90° C. for 12-36 hours to obtain the fluorescent probe.

7. The method for preparing a fluorescent probe for detecting zinc ions in water according to claim 6, wherein: The following steps are involved: S1. o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene were mixed in a container at a molar ratio of 1:1, and then NaOH and ethanol were added. The mixture was ultrasonically dispersed for 30 minutes and stirred at 100° C. for 6 hours to obtain a product solution. The ratio of the total mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to the mass of NaOH is 1:0.01; the volume ratio of the sum of the mass of o-phenylenediamine and 2,6-dialdehyde-1,5-dihydroxynaphthalene to ethanol is 1:50, measured in g and mL. S2. The product solution was centrifuged to collect the solid product, which was washed with ethanol three times and then vacuum-dried at 60° C. for 24 h to obtain the fluorescent probe.

8. A fluorescent probe for detecting zinc ions in water, characterized in that: It is prepared by the method according to any one of claims 1 to 7.

9. A method for detecting zinc ions in water, characterized in that: The following steps are involved: 1) dispersing the fluorescent probe according to claim 8 in ethanol to prepare a probe solution, and measuring the fluorescence intensity of the probe solution at 572 nm under 320-600 nm excitation light, which is recorded as F0; 2) The probe solution was mixed with zinc ion standard solutions of different concentrations and reacted for 2-10 minutes. The fluorescence intensity of the resulting product was measured at 572 nm under excitation light of 320-600 nm, recorded as F. A standard curve was constructed based on the different zinc ion concentrations and the corresponding F / F0 values; 3) Monitor the fluorescence intensity of a solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 572 nm under excitation light of 320-600 nm, record it as F', calculate the value of F' / F0, and use a pre-constructed standard curve to calculate the zinc ion concentration in the sample to be tested.

10. The method for detecting zinc ions in water according to claim 9, wherein The following steps are involved: 1) dispersing the fluorescent probe according to claim 8 in ethanol to prepare a probe solution, and measuring the fluorescence intensity of the probe solution at 572 nm under 460 nm excitation light, which is recorded as F0; 2) The probe solution was mixed with zinc ion standard solutions of different concentrations and reacted for 5 minutes. The fluorescence intensity of the resulting product at 572 nm under 460 nm excitation light was measured, recorded as F. A standard curve was constructed based on different zinc ion concentrations and the corresponding F / F0 values; 3) Monitor the fluorescence intensity of a solution obtained by mixing the water sample to be tested and the probe in a volume ratio of 1:1 at 572 nm under excitation light of 460 nm, record it as F', calculate the value of F' / F0, and use the pre-constructed standard curve to calculate the zinc ion concentration in the sample to be tested.

Images