CN113831236A - Detect Al3+Fluorescent probe and preparation method and application thereof - Google Patents

Abstract

The invention discloses a method for detecting Al³⁺The invention takes monohydroxy poly tetraphenyl ethylene with AIE (aggregation induced emission) property as a fluorophore, reacts with 3-bromobutyric acid methyl ester, and then hydrolyzesPreparing a para-Al³⁺Fluorescent detection probes with selectivity, specificity and sensitivity. Compared with the fluorescence detection technology in the prior art, the fluorescence detection probe has the advantages of simple synthesis, low cost, high reaction speed and high sensitivity, and can be used for real-time in-situ detection.

Description

Detect Al3+Fluorescent probe and preparation method and application thereof

Technical Field

The invention discloses a method for detecting Al³⁺Belonging to the field of chemical material preparation and analysis and detection.

Background

Aluminum is one of the most abundant metals in the earth crust, which is closely related to our life, and the aluminum element has been widely applied to industries such as food additives, medicines, water purification, packaging and the like, but any substance has two sides, for example, when the silicate mineral containing aluminum contacts acid rain, the metal is easily taken out from the mineral, so that the content of aluminum in the environment or water is increased, the crop growth is not facilitated, and soil acidification is also increased; for example, long term exposure to aluminum ions or excessive intake of aluminum may lead to accumulation in different organsA large amount of aluminum ions are susceptible to various diseases, most commonly causing neurological diseases. Therefore, the amount of Al contained in the sample is very small³⁺It is important to perform sensitive and selective detection.

There are many methods for detecting aluminum in the prior art, such as atomic absorption spectroscopy, plasma atomic generation spectroscopy, etc., which are generally time-consuming and expensive, and some probes for detecting aluminum using fluorescence technology are reported, but the strong hydration of aluminum ions in an aqueous medium generally results in poor coordination ability and is easily interfered by other substances. Compared with the fluorescence detection method in the prior art, the method uses the AIE (aggregation induced emission) compound to give a detection signal through aggregation luminescence, and prepares the fluorescence probe system which has high specificity and sensitivity and can be used for aluminum ion analysis in actual life.

Disclosure of Invention

The invention aims to provide a method for detecting Al³⁺The fluorescent probe and the preparation method and the application thereof solve the problem that the detection of aluminum ions by a fluorescence detection method in the prior art is easily interfered by other substances. The invention takes monohydroxy tetraphenyl ethylene (TPE-OH) with AIE property as a fluorophore, reacts with 3-methyl bromoalkyl acid, and then is hydrolyzed to prepare the para-Al³⁺Fluorescent detection probes with selectivity, specificity and sensitivity. The detection Al³⁺The fluorescent probe has a structure shown in a formula (I):

in the formula (I), n is 3, and the fluorescent probe detects Al³⁺The lower detection limit of (3) is less than 20 nM. Compared with the fluorescence detection technology in the prior art, the fluorescence detection probe has the advantages of simple synthesis, low cost, high reaction speed and high sensitivity, and can be used for real-time in-situ detection.

Correspondingly, the invention also provides a preparation method of the fluorescent probe, which comprises the following steps:

step one, synthesizing TPE-OH

Adding zinc powder, 4-hydroxybenzophenone, benzophenone and anhydrous tetrahydrofuran in sequence into a two-mouth reaction bottle, and stirring in an ice bath to obtain a mixed solution; adding TiCl to the mixed solution₄And after the addition, removing the ice bath to perform room temperature reaction, performing heating reflux reaction for 12-24h, stopping heating, cooling to room temperature, adding a quenching solution to quench, performing silica gel column chromatography, collecting a product, and performing vacuum drying to obtain the TPE-OH.

Step two, synthesizing TPE-Cn-COOH

Adding DMF, the TPE-OH, methyl bromoalkanoate and K into the other two-mouth reaction bottle in sequence₂CO₃In N at₂Carrying out normal temperature reaction in the atmosphere, purifying through a silica gel column after the reaction is finished, dissolving a purified product in a methanol solution, then mixing with alkali and carrying out stirring reaction at room temperature to obtain a white crystal; and filtering the white crystals to obtain TPE-Cn-COOH, wherein the methyl bromoalkyl acid ester is methyl 4-bromobutyrate.

The synthetic route of the TPE-Cn-COOH is as follows:

in the above synthetic formula, n is 2,3, 4.

Preferably, in the step one: before adding the zinc powder, filling N by vacuumizing₂The method of (3) removes water and oxygen from the two-necked reaction flask 3 times.

Preferably, in the step one: the molar ratio of the 4-hydroxybenzophenone to the benzophenone is 1:1-1.5, and the molar mass of the zinc powder is 4-5 times that of the 4-hydroxybenzophenone.

Preferably, TiCl is added to the mixed solution₄The method specifically comprises the following steps:

after the benzophenone was added to the two-necked reaction flask for 20 minutes, the TiCl was injected by syringe₄Adding the mixture into the mixed solution.

Preferably, in saidIn the first step: the reaction time of the room temperature reaction was 30 minutes, the reaction time of the heating reflux reaction was 12 hours, and the quenching solution was 10% K₂CO₃An aqueous solution.

Preferably, in the second step: the mol ratio of the TPE-OH to the methyl 4-bromobutyrate is 1:2-4, and the TPE-OH to the K₂CO₃The molar ratio of (1: 4) - (5), and the reaction time of the normal-temperature reaction is 6-18 h.

Preferably, in the second step: the alkali is aqueous solution of NaOEt, the molar ratio of the purified product to the NaOEt is 1:1-5, and the reaction time of the stirring reaction is 5-10 h.

Correspondingly, the invention also provides the fluorescent probe for detecting Al³⁺The fluorescent probe is used for detecting Al³⁺The lower detection limit of (3) is 14 nM.

The fluorescent probe TPE-Cn-COOH based on tetraphenylethylene and with different chain segment lengths is synthesized and used for detecting Al³⁺Comparing the detection efficiency of the fluorescent probes with different chain segment lengths, the result shows that when n is 3, the fluorescent probes are used for Al³⁺Has the best detection effect, and can accurately detect the Al in the water body³⁺The concentration of (A) has good selectivity, sensitivity and specificity, and the lower limit of detection is lower than 20 nM.

Drawings

FIG. 1 shows Al detection with fluorescent probes prepared according to different embodiments of the present invention³⁺Fluorescence emission spectrum of (a); the abscissa is the wavelength (unit: nm) and the ordinate is the fluorescence intensity; example 1 is example 1, comparative example 1 is comparative example 2 is comparative example 3.

FIG. 2 is a graph of comparative data on the selectivity of fluorescent probes for various metal ions, provided in example 1 of the present invention; the abscissa is the metal ion type and the ordinate is the fluorescence intensity.

FIG. 3 is a diagram of fluorescent probe for detecting different Al according to example 1 of the present invention³⁺A plot of fluorescence emission spectra at concentration; the abscissa is the wavelength (unit: nm) and the ordinate is the fluorescence intensity.

FIG. 4 shows a fluorescent probe provided in example 1 of the present inventionNeedle with Al³⁺A fitted curve of fluorescence intensity with varying concentration; the abscissa is Al³⁺Concentration (. mu.M), and the ordinate represents the fluorescence intensity.

FIG. 5 shows a fluorescent probe provided in example 1 of the present invention on Al³⁺Fluorescence emission spectra in the presence of different metal ions; the abscissa is the metal ion type and the ordinate is the fluorescence intensity.

Detailed Description

The invention will be described in further detail with reference to the following figures and specific embodiments:

synthesis of TPE-OH

A250 mL two-necked reaction flask was prepared and first evacuated and filled with N₂After removing water and oxygen from the reaction flask for 3 times, 2.9g (44mmol) of zinc powder, 2g (10mmol) of 4-hydroxybenzophenone, 2.184g (12mmol) of benzophenone and 100mL of anhydrous THF were sequentially added to the reaction flask, and the mixture was stirred in an ice bath to obtain a mixed solution. After 20 minutes, 2.5mL (22mmol) of TiCl are withdrawn by syringe₄Slowly adding into the mixed solution, removing ice bath after adding, standing at room temperature for 0.5h, and heating under reflux overnight. Stopping heating the next day, cooling to room temperature, and adding 10% K₂CO₃Quenching with water solution, filtering, spin-drying the filtrate, extracting with diethyl ether and water for 3 times, mixing diethyl ether layers, extracting with 5% saline water for 2 times, collecting diethyl ether layer, and collecting the extractive solution with anhydrous MgSO₄And (5) drying. The product was spun off and chromatographed on silica gel. And collecting the product, and drying in vacuum to obtain TPE-OH. The structural formula of the TPE-OH is as follows:

the Nuclear Magnetic Resonance (NMR) spectrum of the TPE-OH is as follows: 1H NMR (400MHz, DMSO-d6): Δ 9.34(s,1H),7.06-7.14(m,9H),6.93-6.98(m,6H),6.73-6.75(d,2H),6.47-6.52(d, 2H). Wherein 9.34ppm of peak is H on OH, and 7.14-6.47ppm of peak is H on benzene ring.

EXAMPLE 1 Synthesis of TPE-C3-COOH

In a two-necked reaction flask, 15mL of DMF and 0.174g (0.5 m) of DMF were sequentially addedmol) TPE-OH, 181mg (1mmol) methyl 4-bromobutyrate and 276mg (2mmol) K₂CO₃Introducing N at normal temperature₂Reacting for 12h, and purifying the product through a silica gel column. 448mg (1mmol) of the purified product was dissolved in a methanol solution (10ml), and then mixed with 103mg (1.5mmol) of aqueous NaOEt solution and stirred at room temperature, after 6h, white crystals were obtained, and TPE-C3-COOH was obtained by filtration. The structural formula of the TPE-C3-COOH is as follows:

the Nuclear Magnetic Resonance (NMR) spectrum of the TPE-C3-COOH is as follows: 1H NMR (400MHz, CD3OD): Δ 7.05(m,9H),6.97(m,6H),6.88(d,2H),6.64(d,2H),3.53(t,2H),1.84(t,2H),1.56(m, 2H). Among them, 7.05-6.64ppm of peak is hydrogen on benzene ring, 3.53ppm is H at a, 1.84ppm is H at b, and 1.56ppm is H at c.

Comparative example 1 TPE-C1-COOH synthesized according to anal. chem.2015,87,1470-

The structural formula of the TPE-C1-COOH is as follows:

the Nuclear Magnetic Resonance (NMR) spectrum of the TPE-C1-COOH is as follows: 1H NMR (400MHz, CD3OD): Δ 7.05(m,9H),6.98(m,6H),6.88(d,2H),6.66(d,2H),4.43(s, 2H). Wherein the peak at 7.05-6.66ppm is hydrogen on benzene ring and 4.43ppm is H at a.

Comparative example 2 Synthesis of TPE-C2-COOH

Into a two-necked reaction flask were sequentially charged 15mL of DMF, 0.174g (0.5mmol) of TPE-OH, 167mg (1mmol) of methyl 3-bromopropionate and 276mg (2mmol) of K₂CO₃Introducing N at normal temperature₂Reacting for 12h, and purifying the product through a silica gel column. 434mg (1mmol) of the purified product were dissolved in methanol solution (10ml), mixed with 103mg (1.5mmol) of aqueous NaOEt solution and stirred at room temperature, after 6h, white crystals were obtained, TPE-C2-COOH being obtained by filtration. The structural formula of the TPE-C2-COOH is as follows:

the Nuclear Magnetic Resonance (NMR) spectrum of the TPE-C2-COOH is as follows: 1H NMR (400MHz, CD3OD): Δ 7.03(m,9H),6.95(m,6H),6.86(d,2H),6.63(d,2H),3.82(t,2H),2.26(t, 2H). Wherein the peak at 7.03-6.63ppm is hydrogen on benzene ring, 3.82ppm is H at a, and 2.26ppm is H at b.

Comparative example 3 Synthesis of TPE-C4-COOH

Into a two-necked reaction flask were sequentially charged 15mL of DMF, 0.174g (0.5mmol) of TPE-OH, 181mg (1mmol) of methyl 5-bromovalerate and 276mg (2mmol) of K₂CO₃Introducing N at normal temperature₂Reacting for 12h, and purifying the product through a silica gel column. 462mg (1mmol) of the purified product were dissolved in methanol solution (10ml), mixed with 103mg (1.5mmol) of aqueous NaOEt solution and stirred at room temperature, after 6h, white crystals were obtained, TPE-C4-COOH was obtained by filtration. The structural formula of the TPE-C4-COOH is as follows:

the Nuclear Magnetic Resonance (NMR) spectrum of the TPE-C4-COOH is as follows: 1H NMR (400MHz, CD3OD): Δ 7.06(m,9H),6.98(m,6H),6.87(d,2H),6.66(d,2H),3.52(t,2H),1.86(t,2H),1.12-1.46(m, 4H). Wherein the peak at 7.06-6.66ppm is H on benzene ring, the peak at 3.52ppm is H at a, the peak at 1.86ppm is H at b, and the peak at 1.12-1.46ppm is H at c.

Experimental example 1 responsiveness of different fluorescent probes to metal ions

Preparation of various Metal ions (Ba) with ultrapure Water²⁺,Fe²⁺,Ca²⁺,Mg²⁺,Cr³⁺,Li⁺,Zn²⁺,Hg²⁺,Pb²⁺,Na⁺,Ag⁺,Fe³⁺,K⁺,Ni²⁺,Cu²⁺And Al³⁺) Stock (0.25m M) of probes (TPE-Cn-COOH) was prepared in DMSO (1 mM).

At the time of detection, 20. mu. L, Al of the probe stock solution was taken out³⁺Stock solution 10. mu.L, 455. mu.lPreparing solution to be tested with L deionized water and 25 μ L acetonitrile, incubating at room temperature for 30min, and recording fluorescence emission spectrum with fluorescence spectrometer (excitation wavelength: 310nm, scanning wavelength range: 350nm-600nm, probe concentration of 40 μ M, Al³⁺Ion concentration 5. mu.M).

As shown in FIG. 1, when the probe used was the fluorescent probe of example 1, the strongest fluorescence was at 480nm, and the fluorescence intensity was 415; when the probe used was the fluorescent probe of comparative examples 1 to 3, the strongest fluorescence was at 475nm, and the fluorescence intensities were 105, 66, and 60, respectively. From this, it is understood that the probe of example 1 is directed to Al³⁺Has higher responsiveness. This is probably due to the fluorescent probe of TPE-C3-COOH and Al³⁺Can form more stable complexation and has better size matching property.

And (3) selective testing of the probe: the TPE-C3-COOH synthesized in example 1 was used as a fluorescent probe, 15 representative metal ions with different valence states were selected for binding experiments with the probe, and the probe and Al were examined by fluorescence spectroscopy³⁺Selectivity of the interaction. During detection, 20 mu L of probe stock solution and 10 mu L of single metal ion stock solution are taken out, 455 mu L of deionized water and 25 mu L of acetonitrile are added to prepare a solution to be detected, the solution is incubated for 30min at room temperature, and a fluorescence emission spectrum (excitation wavelength: 310nm, scanning wavelength range: 350nm-600nm, probe concentration of 40 mu M and metal ion concentration of 5 mu M) is recorded by a fluorescence spectrometer.

The test result is shown in FIG. 2, the TPE-C3-COOH synthesized in example 1 is used as a fluorescent probe, and the fluorescent probe does not respond to common metal ions and only responds to Hg²⁺And Pb²⁺Has weak response, so the probe is opposite to Al³⁺The detection is selective.

Experimental example 2 use of TPE-C3-COOH on Al³⁺Detection experiment of

The different Al's were tested according to the method of example 2³⁺The fluorescence intensity at concentration, shown in FIG. 3, is dependent on Al³⁺The fluorescence of the system is continuously enhanced due to the increased concentration, which is probably caused by Al³⁺The addition of (b) results in a constant aggregation of the probes, forming hydrophobic aggregates, resulting in an increase in fluorescence.

Extraction of Al³⁺The concentration is 0, 0.5, 1, 1.5, 2 μ M, and the maximum fluorescence emission intensity of the system at 480nm is corrected to obtain the working curve as shown in FIG. 4. And obtaining the lowest detection lower limit through the working curve. The lower limit of detection (LOD) is 3 × s.d./k. Wherein k represents the slope of the curve and S.D represents the slope at Al³⁺Standard deviation at a concentration of 0.

I₄₈₀＝10+199.8×[Al³⁺]

LOD 3 × 0.948/199.8 0.014 μ M, so this system Al was obtained³⁺The lower detection limit of (2) is 14nM, which is lower than the lower detection limit of the known literature.

Experimental example 3 comparative detection experiment of influence of other ions.

TPE-C3-COOH synthesized in example 1 was used as a fluorescent probe, and 15 representative metal ions with different valence states and Al were selected respectively³⁺Simultaneously, the combination experiment with the probe is carried out, and Al of other metal ions is investigated through fluorescence spectrum measurement³⁺The effect of the detection. During detection, 20. mu.L of the probe stock solution and 10. mu. L, Al of the metal ion stock solution were taken out³⁺Adding 455 mu L deionized water and 25 mu L acetonitrile into 10 mu L stock solution to prepare solution to be tested, incubating at room temperature for 30min, and recording fluorescence emission spectrum by fluorescence spectrometer (excitation wavelength: 310nm, scanning wavelength range: 350nm-600nm, probe concentration of 40 mu M, other metal ion concentration of 5 mu M, Al³⁺Concentration 5 μ M).

The test results are shown in FIG. 5 (Al)³⁺The group is a control group and does not contain other metal ions), and the result shows that the TPE-C3-COOH synthesized in example 1 is a fluorescent probe, and the prepared fluorescent probe detects Al in the presence of the metal ions³⁺The fluorescence intensity of the probe has no obvious influence, and the anti-interference performance of the probe is better.

Experimental example 4 detection of Al in tap Water by Probe³⁺Test (2)

In order to investigate Al in actual water sample by probe³⁺The test was performed in tap water.

Testing tap water by inductively coupled plasma atomic emission spectrometryAl³⁺The content of (A) is 2.1. mu.M, while the result detected by the fluorescent probe synthesized in our example 1 is 2.07. mu.M, and the results of the two tests are very close. Additionally adding Al with known amount³⁺Through the detection of the fluorescent probe, the detection result is compared with the inductively coupled plasma atomic emission spectrometry test result to obtain the difference between the two results, and the experimental result is as follows:

the test result shows that the prepared probe has higher accuracy and reliability (the recovery rate is between 98.5% and 102.5%), the interference of other ions in tap water to the probe is small, and the fluorescence detection has higher precision compared with ICP-AES generally through the calculation of relative standard deviation, so the precision of the fluorescence probe can be comparable with the ICP-AES, and the fluorescence probe is convenient to use and can be used for one-step detection.

The above disclosure is only illustrative of the embodiments of the present invention, and is not intended to limit the present invention in any way, and any methods and materials similar or equivalent to those described herein can be used in the method of the present invention. The preferred embodiments and materials described herein are exemplary only, and the embodiments of the present application are not intended to be limited thereto, since modifications and variations of the disclosed embodiments may occur to those skilled in the art and are intended to be included within the scope of the appended claims. The above sequence numbers are for illustrative purposes only and do not represent the relative merits of the implementation scenario. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention, without departing from the technical solution of the present invention, still belong to the protection scope of the technical solution of the present invention.

Claims (10)

1. Detect Al³⁺The fluorescent probe of (2), wherein the fluorescent probe has a structure represented by formula (I):

in the formula (I), n is 3, and the fluorescent probe detects Al³⁺The lower detection limit of (3) is less than 20 nM.

2. A method of preparing a fluorescent probe according to claim 1, comprising the steps of:

step one, adding zinc powder, 4-hydroxybenzophenone, benzophenone and anhydrous tetrahydrofuran in sequence into a two-mouth reaction bottle, and stirring in an ice bath to obtain a mixed solution; adding TiCl to the mixed solution₄After the reaction is finished, removing the ice bath to carry out room temperature reaction, then carrying out heating reflux reaction for 12-24h, stopping heating, cooling to room temperature, adding a quenching solution to quench, then carrying out silica gel column chromatography, collecting a product, and carrying out vacuum drying to obtain TPE-OH;

step two, sequentially adding DMF, TPE-OH, methyl bromoalkanoate and K into another two-mouth reaction bottle₂CO₃In N at₂Carrying out normal temperature reaction in the atmosphere, purifying through a silica gel column after the reaction is finished, dissolving a purified product in a methanol solution, then mixing with alkali and carrying out stirring reaction at room temperature to obtain a white crystal; and filtering the white crystals to obtain TPE-Cn-COOH, wherein the methyl bromoalkyl acid ester is methyl 4-bromobutyrate.

3. The production method according to claim 2, wherein in the step one: before adding the zinc powder, filling N by vacuumizing₂The method of (3) removes water and oxygen from the two-necked reaction flask 3 times.

4. The production method according to claim 2, wherein in the step one: the molar ratio of the 4-hydroxybenzophenone to the benzophenone is 1:1-1.5, and the molar mass of the zinc powder is 4-5 times that of the 4-hydroxybenzophenone.

5. The method according to claim 2, wherein TiCl is added to the mixed solution₄The method specifically comprises the following steps:

after the benzophenone was added to the two-necked reaction flask for 20 minutes, the TiCl was injected by syringe₄Adding the mixture into the mixed solution.

6. The production method according to claim 2, wherein in the step one: the reaction time of the room temperature reaction was 30 minutes, the reaction time of the heating reflux reaction was 12 hours, and the quenching solution was 10% K₂CO₃An aqueous solution.

7. The production method according to claim 2, characterized in that, in the step two: the mol ratio of the TPE-OH to the methyl 4-bromobutyrate is 1:2-4, and the TPE-OH to the K₂CO₃The molar ratio of (1: 4) - (5), and the reaction time of the normal-temperature reaction is 6-18 h.

8. The production method according to claim 2, characterized in that, in the step two: the alkali is aqueous solution of NaOEt, the molar ratio of the purified product to the NaOEt is 1:1-5, and the reaction time of the stirring reaction is 5-10 h.

9. The method for detecting Al by using the fluorescent probe as defined in claim 1³⁺The use of (1).

10. The use of claim 9, wherein the fluorescent probe detects Al³⁺The lower detection limit of (3) is 14 nM.

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