Application of ratio type fluorescent probe in quantitative detection of copper ions and / or iron ions

Abstract

The invention belongs to the technical field of analysis and detection, and discloses application of a ratio type fluorescent probe in quantitative detection of copper ions and / or iron ions. The fluorescent probe takes lanthanide metals Tb, Eu, Dy, Sm, Pr, Ho, Er and the like as central metals, Y, Gd, La and Lu as matrixes and benzenetricarboxylic acid as a ligand to be coordinated and combined with lanthanide ions to form a lanthanide coordination polymer. The fluorescent probe takes the luminescence change of the green fluorescence of the Tb-MOFs at PEI in Cu < 2 + > or Fe < 3 + > as a reference, and when Cu < 2 + > or Fe < 3 + > is added into a sensing system, the luminescence intensity of the Tb-MOFs at PEI can be reduced due to the concentration quenching effect. The detection method provided by the invention has the advantages of simplicity, rapidness, good specificity and obvious effect on two luminescence peaks of Tb < 3 + >. The detection range of Cu < 2 + > is 5 nM to 100 [mu] M, the detection limit is 9.7 nM, the detection range of Fe < 3 + > is 50 nM to 500 [mu] M, and the detection limit is 37.4 nM.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and detection, and particularly relates to application of a ratiometric fluorescent probe in quantitative detection of copper ions and / or iron ions. Background Art

[0002] Copper and iron are essential trace elements for the human body. They play a vital role in maintaining life activities and physiological functions. However, excessive intake or accumulation of these elements can also pose a serious threat to human health. First of all, copper is a component of many enzymes that are involved in energy metabolism, antioxidant defense, nerve conduction, and the formation of connective tissue. Copper is also essential for the formation of blood and affects the synthesis of hemoglobin. In addition, copper is also essential for maintaining the health of the central nervous system. It helps the synthesis of neurotransmitters and the transmission of nerve signals. In the immune system, copper helps the function of white blood cells and enhances the body's resistance. However, excessive accumulation of copper can lead to copper poisoning, especially damage to brain neurons, which may increase the risk of neurological diseases such as Alzheimer's disease, Wilson's disease, and Parkinson's disease. Iron is the main component of hemoglobin and myoglobin, two proteins responsible for transporting oxygen in the blood and ensuring that all parts of the body get enough oxygen supply. Iron is also involved in energy metabolism and DNA synthesis. In the immune system, iron is also necessary to maintain normal immune function. However, excessive intake or absorption of iron can lead to iron poisoning. Symptoms of acute iron poisoning in children may include vomiting, diarrhea, lethargy and shock, and in severe cases may even be life-threatening. Long-term excessive iron intake in adults may lead to chronic iron poisoning, in which case the accumulation of iron in the liver and other organs may lead to chronic diseases such as cirrhosis, osteoporosis and diabetes.

[0003] At present, the commonly used heavy metal ion detection methods mainly include ultraviolet visible spectrophotometry, atomic absorption spectrometry, atomic fluorescence, inductively coupled plasma emission spectrometry, inductively coupled plasma mass spectrometry, mass spectrometry, electrochemical method and X-ray fluorescence spectrometry. However, these methods generally have the problems of long time consumption, high cost, expensive instruments, complex operation, low sensitivity and poor selectivity. Therefore, it is extremely important to develop a new method for heavy metal ion detection that is simple to operate, cost-effective and highly sensitive.

[0004] In recent years, fluorescence analysis, as a highly sensitive and highly selective analytical technique, has developed rapidly in the field of heavy metal ion detection. The core of fluorescence analysis is to use the interaction between heavy metal ions and specific fluorescent reagents to form a complex with fluorescent properties, thereby realizing the accurate determination of the concentration of heavy metal ions. When heavy metal ions combine with fluorescent reagents to form a complex, the complex can emit fluorescence of a specific wavelength under the excitation of ultraviolet-visible light. By detecting the intensity change of this fluorescence, the concentration of heavy metal ions can be indirectly determined. The advantage of this method is its high sensitivity and high selectivity. It can detect extremely low concentrations of heavy metal ions and has little interference with other ions. Therefore, as an advanced analytical technique, fluorescence analysis has broad application prospects in the field of heavy metal ion detection. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the traditional fluorescence method relies on a single peak and is easily disturbed by the environment and has inaccurate detection, and to provide a ratiometric lanthanide fluorescent probe for detecting copper ions and iron ions. 2+ and Fe 3+ It achieves high sensitivity, high precision, and simple rapid detection. Its operation process is simple, the cost is low, and the test results have good reproducibility.

[0006] To achieve the above object, the technical solution of the present invention is as follows: an application of a ratiometric fluorescent probe in the quantitative detection of copper ions and / or iron ions, the method is as follows:

[0007] 1) A series of 500 μM, 100 μM, 50 μM, 10 μM, 5 μM, 1 μM, 500 nM, 100 nM, 50 nM and 10 nM CuCl2 and / or FeCl3 solutions were used as test samples. 200 μL of CuCl2 and / or FeCl3 solutions of specific concentrations were added to the solution. 2+ or Fe 3+ The solution was added to a cuvette, and then 800 μL of ratiometric fluorescent probe Ln-MOFs@PEI was placed in the dispersion, pH was adjusted to 8, and the sample was tested under a spectrometer after ultrasonic homogenization; I 546 nm / I 402 nm With Cu 2+ The linear relationship between 546 nm / I 402nm with Fe 3+ The linear relationship between

[0008] 2) Containing Cu 2+ and / or Fe 2+800 μL of Ln-MOFs@PEI was added to the solution, pH was adjusted to 8, and the sample was tested under a spectrometer after ultrasonic homogenization. The concentration of Ln-MOFs@PEI in the mixed solution was 1 mg / mL. The Cu 2+ and / or Fe 3+ concentration.

[0009] In the above application, the ratiometric fluorescent probe Ln-MOFs@PEI is based on lanthanide metals Tb, Eu, Dy, Sm, Pr, Ho, Er as central metals, Y, Gd, La, Lu as matrix, and benzenetricarboxylic acid as ligand to coordinate with lanthanide ions to form a lanthanide coordination polymer.

[0010] In the above application, the preparation method of the ratiometric fluorescent probe Ln-MOFs@PEI comprises the following steps:

[0011] 1) Preparation of Ln-MOFs: lanthanide metal compounds, Y(NO3)3, and CH3COONa were dissolved in deionized water, and ultrasonicated with H3BTC and DMF solution to obtain a white solution, which was allowed to stand at a certain temperature, washed, and white precipitates were collected. The white precipitates were dispersed in methanol for activation, washed, and vacuum dried to obtain white powder of Ln-MOFs;

[0012] 2) Preparation of Ln-MOFs@PEI: Disperse Ln-MOFs in PEI solution, stir at room temperature, collect by centrifugation, wash with deionized water, and freeze-dry to obtain Ln-MOFs@PEI.

[0013] In the above application, the lanthanide ion in the lanthanide compound is one of Tb, Eu, Dy, Sm, Pr, Ho, and Er.

[0014] In the above application, in step 1), the standing at a certain temperature is standing at 60° C. for 24 hours and then cooling to room temperature.

[0015] In the above application, in step 1), the molar ratio of lanthanide metal compound: Y(NO3)3: CH3COONa is 10:90:1.

[0016] In the above applications, the Ln-MOFs@PEI fluorescent probe can have two or more obvious emission characteristic peaks in the spectral range. After the addition of copper ions or iron ions, the intensity of the emission peak changes, and the peak ratio is used to detect the concentration of copper ions or iron ions.

[0017] The above application, the Ln-MOFs@PEI fluorescent probe, is characterized by: 3+ Can be replaced by Gd 3+ , La 3+ or Lu3+ .

[0018] The ratiometric fluorescent probe spectrum is a multi-peak emission of a specific wavelength generated under ultraviolet or near-infrared light irradiation. For example, the luminescence peaks of Tb-MOFs@PEI composite materials under ultraviolet light excitation are located near 545nm and 402nm. For example, the luminescence peaks of Eu-MOFs@PEI composite materials under ultraviolet light excitation are located near 613nm and 402nm. For example, the luminescence peaks of Dy-MOFs@PEI composite materials under ultraviolet light excitation are located near 574nm and 402nm. For example, the luminescence peaks of Sm-MOFs@PEI composite materials under ultraviolet light excitation are located near 599nm and 402nm. For example, the luminescence peaks of Pr-MOFs@PEI composite materials under ultraviolet light excitation are located near 605nm and 402nm. For example, the luminescence peaks of Ho-MOFs@PEI composite materials under 980nm infrared light excitation are located near 456nm and 402nm. For example, the Er-MOFs@PEI composite material produces luminescence peaks near 545nm and 402nm under 980nm infrared light excitation.

[0019] Ln-MOFs@PEI ratiometric fluorescent probe has the following advantages:

[0020] Most of the developed fluorescence sensors are usually single signal, which is easily affected by factors such as instrument parameters and environment, resulting in inaccurate experimental results. 3+ The fluorescence ratio of the green fluorescence and benzene trimeric acid signals is used as the readout signal, which is not easily affected by instrument factors, thus ensuring the accuracy of the test results. 3+ After changing to Eu, Dy, Sm, Pr, Ho, and Er ions, the luminescence intensity of Ln-MOFs@PEI still increases with the Cu 2+ or Fe 3+ This maintains the accuracy of the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the XRD pattern of Ln-MOFs.

[0022] Figure 2 Ln-MOFs@PEI-Cu 2+ Normalized absorption (black) and emission (blue) spectra of .

[0023] Figure 3 To add different concentrations of Cu 2+ Emission spectrum of Ln-MOFs@PEI solution.

[0024] Figure 4 For I546 nm / I 402 nm With Cu 2+ The linear relationship between them.

[0025] Figure 5 To add different concentrations of Fe 3+ Emission spectrum of Ln-MOFs@PEI solution.

[0026] Figure 6 For I 546 nm / I 402 nm with Fe 3+ The linear relationship between them. DETAILED DESCRIPTION

[0027] Example 1 Preparation of Tb-MOFs@PEI fluorescent probe

[0028] 1) Preparation of Tb-MOFs by hot solvent method: 0.0093g Tb(NO3)3, 0.3524g Y(NO3)3 and 0.0014g CH3COONa were dissolved in 22.6mL deionized water. The solution was ultrasonicated with H3BTC and 40mL DMF solution for 30 minutes to obtain a white solution. The white solution was added to the reactor, placed at 60°C for 24 hours, and then cooled to room temperature. The reactants were centrifuged and washed with DMF 3 times. The white precipitate was collected and then dispersed in 50mL methanol for activation for 24 hours. Finally, it was washed 3 times with methanol. The product was placed in a vacuum oven at 80°C for 12 hours to obtain a white powder of Tb-MOFs. Figure 1 is the XRD spectrum of Tb-MOFs. The diffraction peaks correspond to those of the JUC-32 standard card, which means that Tb 3+ and Y 3+ The concentration change has no effect on the crystal structure. Figure 2 Tb-MOFs@PEI-Cu 2+ The normalized absorption and emission spectra of Tb overlap, indicating that the inner filter effect has an important influence on the 3+ Contribution of luminescence quenching.

[0029] 2) Disperse Tb-MOFs in polyethyleneimine (PEI) solution (1 mM, 20 mL) and stir at room temperature for 2 hours to functionalize its surface. Collect Tb-MOFs@PEI by centrifugation and wash with deionized water three times. Place the product in a vacuum freeze dryer for 24 hours to obtain a powder sample of Tb-MOFs@PEI.

[0030] 3) A series of specific concentrations (500 μM, 100 μM, 50 μM, 10 μM, 5 μM, 1 μM, 500 nM, 100 nM, 50 nM and 10 nM) of CuCl2 and FeCl3 solutions were used as test samples. 200 μL of specific concentrations of Cu 2+ or Fe 3+ The solution was added to a cuvette and used as the object to be detected. Then 800 μL of Tb-MOFs@PEI was placed in the dispersion and the pH was adjusted to 8. The concentration of Tb-MOFs@PEI in the solution was 1 mg / mL. After ultrasonic homogenization, the sample was tested under a spectrometer. Figure 3 and Figure 5 For Ln-MOFs@PEI in Cu 2+ and Fe 3+ The luminescence spectrum in solution, along with Cu 2+ or Fe 3+ With the increase of concentration, the emission peak intensity ratio at 546nm and 402nm shows an opposite trend, which is caused by the difference in luminescence quenching mechanism.

[0031] Tb-MOFs@PEI has two characteristic peaks near 545nm and 402nm under the excitation of ultraviolet light. When Tb-MOFs@PEI is added to copper ion and iron ion solutions of different concentrations, the emission peak intensity at 545nm and 402nm will change. The concentration of copper ions and iron ions is detected by the fluorescence intensity ratio of 545nm and 402nm. Figure 4 and Figure 6 The emission peak intensity ratios at 546nm and 402nm are respectively compared with Cu 2+ and Fe 3+ The linear relationship between the solution and the detection of Cu 2+ and Fe 3+ The linear equations are y = -1.72x + 9.59 and y = 1.05x + 7.77, respectively. 2+ The detection range is 5nM-100μM, the detection limit is 9.7nM, and the detection limit is 9.7nM for Fe 3+ The detection range is 50nM-500μM and the detection limit is 37.4nM.

[0032] Example 2 Preparation of Eu-MOFs@PEI fluorescent probe

[0033] The 0.0093 g Tb(NO3)3 in step 1) of Example 1 was replaced with 0.0091 g Eu(NO3)3, and the other steps and operations remained unchanged.

[0034] Eu-MOFs@PEI has two characteristic peaks near 613nm and 402nm under the excitation of ultraviolet light. When Eu-MOFs@PEI is added to copper ion and iron ion solutions of different concentrations, the emission peak intensity at 613nm and 402nm will change. The fluorescence intensity ratio at 613nm and 402nm is used to detect the concentration of copper ions and iron ions.

[0035] Example 3 Preparation of Sm-MOFs@PEI fluorescent probe

[0036] Replace 0.0093 g Tb(NO3)3 in step 1) of Example 1 with 0.0111 g Sm(NO3)3, and the other steps and operations remain unchanged.

[0037] Sm-MOFs@PEI has two characteristic peaks near 599nm and 402nm under the excitation of ultraviolet light. When Sm-MOFs@PEI is added to copper ion and iron ion solutions with different concentrations, the emission peak intensity at 599nm and 402nm will change. The concentration of copper ions and iron ions is detected by the fluorescence intensity ratio of 599nm and 402nm.

[0038] Example 4 Preparation of Pr-MOFs@PEI fluorescent probe

[0039] The 0.0093 g Tb(NO3)3 in step 1) of Example 1 was replaced with 0.0109 g Pr(NO3)3, and the other steps and operations remained unchanged.

[0040] Pr-MOFs@PEI has two characteristic peaks near 605nm and 402nm under the excitation of ultraviolet light. When Pr-MOFs@PEI is added to copper ion and iron ion solutions with different concentrations, the emission peak intensity at 605nm and 402nm will change. The concentration of copper ions and iron ions is detected by the fluorescence intensity ratio at 605nm and 402nm.

[0041] Example 5 Preparation of Ho-MOFs@PEI fluorescent probe

[0042] The 0.0093 g Tb(NO3)3 in step 1) of Example 1 was replaced with 0.0079 g Ho(NO3)3, and the other steps and operations remained unchanged.

[0043] Ho-MOFs@PEI has two characteristic peaks near 456nm and 402nm under 980nm excitation. When Ho-MOFs@PEI is added to copper ion and iron ion solutions with different concentrations, the emission peak intensity at 456nm and 402nm will change. The concentrations of copper ions and iron ions are detected by the fluorescence intensity ratio of 456nm and 402nm.

[0044] Example 6 Preparation of Er-MOFs@PEI fluorescent probe

[0045] The 0.0093 g Tb(NO3)3 in step 1) of Example 1 was replaced with 0.0115 g Er(NO3)3, and the other steps and operations remained unchanged.

[0046] Er-MOFs@PEI has two characteristic peaks near 545nm and 402nm under the excitation of 980nm. When Er-MOFs@PEI is added to copper ion and iron ion solutions with different concentrations, the emission peak intensity at 545nm and 402nm will change. The concentration of copper ions and iron ions is detected by the fluorescence intensity ratio of 545nm and 402nm.

[0047] Example 7 Preparation of Tb-MOFs@PEI fluorescent probe

[0048] In step 1) of Example 1, 0.3524 g of Y(NO3)3 was replaced by 0.4152 g of Gd(NO3)3, and the other steps and operations remained unchanged.

[0049] Example 8 Preparation of Tb-MOFs@PEI fluorescent probe

[0050] In step 1) of Example 1, 0.3524 g of Y(NO3)3 was replaced by 0.2989 g of La(NO3)3, and the remaining steps and operations remained unchanged.

[0051] Example 9 Preparation of Tb-MOFs@PEI fluorescent probe

[0052] In step 1) of Example 1, 0.3524 g of Y(NO3)3 was replaced by 0.3487 g of Lu(NO3)3, and the remaining steps and operations remained unchanged.

[0053] Example 10 Preparation of Eu-MOFs@PEI fluorescent probe

[0054] Replace 0.3524 g of Y(NO3)3 in the step of Example 2 with 0.4152 g of Gd(NO3)3, and the other steps and operations remain unchanged.

[0055] Example 11 Preparation of Eu-MOFs@PEI fluorescent probe

[0056] Replace 0.3524 g Y(NO3)3 in the step of Example 2 with 0.2989 g La(NO3)3, and the other steps and operations remain unchanged.

[0057] Example 12 Preparation of Eu-MOFs@PEI fluorescent probe

[0058] Replace 0.3524 g of Y(NO3)3 in the step of Example 2 with 0.3487 g of Lu(NO3)3, and the other steps and operations remain unchanged.

[0059] Example 13 Preparation of Sm-MOFs@PEI fluorescent probe

[0060] In the step of Example 3, 0.3524 g of Y(NO3)3 was replaced by 0.4152 g of Gd(NO3)3, and the other steps and operations remained unchanged.

[0061] Example 14 Preparation of Sm-MOFs@PEI fluorescent probe

[0062] Replace 0.3524 g Y(NO3)3 in the step of Example 3 with 0.2989 g La(NO3)3, and the other steps and operations remain unchanged.

[0063] Example 15 Preparation of Sm-MOFs@PEI fluorescent probe

[0064] Replace 0.3524 g of Y(NO3)3 in the step of Example 3 with 0.3487 g of Lu(NO3)3, and the other steps and operations remain unchanged.

[0065] Example 16 Preparation of Pr-MOFs@PEI fluorescent probe

[0066] In the step of Example 4, 0.3524 g of Y(NO3)3 was replaced by 0.4152 g of Gd(NO3)3, and the other steps and operations remained unchanged.

[0067] Example 17 Preparation of Pr-MOFs@PEI fluorescent probe

[0068] Replace 0.3524 g Y(NO3)3 in the step of Example 4 with 0.2989 g La(NO3)3, and the other steps and operations remain unchanged.

[0069] Example 18 Preparation of Pr-MOFs@PEI fluorescent probe

[0070] Replace 0.3524 g of Y(NO3)3 in the step of Example 4 with 0.3487 g of Lu(NO3)3, and the other steps and operations remain unchanged.

[0071] Example 19 Preparation of Ho-MOFs@PEI fluorescent probe

[0072] In the step of Example 5, 0.3524 g of Y(NO3)3 was replaced by 0.4152 g of Gd(NO3)3, and the other steps and operations remained unchanged.

[0073] Example 20 Preparation of Ho-MOFs@PEI fluorescent probe

[0074] Replace 0.3524 g of Y(NO3)3 in the step of Example 5 with 0.2989 g of La(NO3)3, and the other steps and operations remain unchanged.

[0075] Example 21 Preparation of Ho-MOFs@PEI fluorescent probe

[0076] In the step of Example 5, 0.3524 g of Y(NO3)3 was replaced by 0.3487 g of Lu(NO3)3, and the other steps and operations remained unchanged.

[0077] Example 22 Preparation of Er-MOFs@PEI fluorescent probe

[0078] In the step of Example 6, 0.3524 g of Y(NO3)3 was replaced by 0.4152 g of Gd(NO3)3, and the other steps and operations remained unchanged.

[0079] Example 23 Preparation of Er-MOFs@PEI fluorescent probe

[0080] Replace 0.3524 g of Y(NO3)3 in the step of Example 6 with 0.2989 g of La(NO3)3, and the other steps and operations remain unchanged.

[0081] Example 24 Preparation of Er-MOFs@PEI fluorescent probe

[0082] Replace 0.3524 g of Y(NO3)3 in the step of Example 6 with 0.3487 g of Lu(NO3)3, and the other steps and operations remain unchanged.

Claims

1. Application of a ratiometric fluorescent probe in the quantitative detection of copper ions and / or iron ions, characterized in that: Here’s how: 1) A series of 500 μM, 100 μM, 50 μM, 10 μM, 5 μM, 1 μM, 500 nM, 100 nM, 50 nM and 10 nM CuCl2 and / or FeCl3 solutions were used as test samples. 200 μL of CuCl2 and / or FeCl3 solutions of specific concentrations were added to the solution. 2+ or Fe 3+ The solution was added to a cuvette, and then 800 μL of ratiometric fluorescent probe Ln-MOFs@PEI was placed in the dispersion, pH was adjusted to 8, and the sample was tested under a spectrometer after ultrasonic homogenization; I 546nm / I 402nm With Cu 2+ The linear relationship between 546nm / I 402nm with Fe 3+ The linear relationship between 2) Containing Cu 2+ and / or Fe 2+ 800 μL of Ln-MOFs@PEI was added to the solution, pH was adjusted to 8, and the sample was tested under a spectrometer after ultrasonic homogenization. The concentration of Ln-MOFs@PEI in the mixed solution was 1 mg / mL. The Cu 2+ and / or Fe 3+ concentration.

2. The use according to claim 1, characterized in that: The ratiometric fluorescent probe Ln-MOFs@PEI is based on lanthanide metals Tb, Eu, Dy, Sm, Pr, Ho, Er as central metals, Y, Gd, La, Lu as matrix, and benzenetricarboxylic acid as ligand to coordinate with lanthanide ions to form a lanthanide coordination polymer.

3. The use according to claim 1, characterized in that: The preparation method of the ratiometric fluorescent probe Ln-MOFs@PEI comprises the following steps: 1) Preparation of Ln-MOFs: lanthanide metal compounds, Y(NO3)3, and CH3COONa were dissolved in deionized water, and ultrasonicated with H3BTC and DMF solution to obtain a white solution, which was allowed to stand at a certain temperature, washed, and white precipitates were collected. The white precipitates were dispersed in methanol for activation, washed, and vacuum dried to obtain white powder of Ln-MOFs; 2) Preparation of Ln-MOFs@PEI: Disperse Ln-MOFs in PEI solution, stir at room temperature, collect by centrifugation, wash with deionized water, and freeze-dry to obtain Ln-MOFs@PEI.

4. The use according to claim 1, characterized in that: The lanthanide ions in lanthanide compounds are Tb, Eu, Dy, Sm, One of Pr, Ho, Er.

5. The use according to claim 1, characterized in that: In step 1), the standing at a certain temperature is standing at 60° C. for 24 hours and then cooling to room temperature.

6. The use according to claim 1, characterized in that: In step 1), the molar ratio of lanthanide metal compound: Y(NO3)3: CH3COONa is 10:90:

1.

7. The use according to claim 1, characterized in that: The Ln-MOFs@PEI fluorescent probe can have two or more obvious emission characteristic peaks within the spectral range. After the addition of copper ions or iron ions, the intensity of the emission peak changes, and the peak ratio is used to detect the concentration of copper ions or iron ions.

8. The use according to claim 1, characterized in that: The Ln-MOFs@PEI fluorescent probe is characterized in that: 3+ Can be replaced by Gd 3+ , La 3+ or Lu 3+ .

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