Hg < 2 + > fluorescent probe based on benzo-alpha-pyran as well as preparation method and application of Hg < 2 + > fluorescent probe

Abstract

The invention provides a benzo-alpha-pyran-based Hg < 2 + > fluorescent probe, which is prepared by the following steps: dissolving benzoic acid and pyrrolidine in dimethyl sulfoxide, sequentially adding cinnamyl aldehyde and 5-methoxy-2-hydroxy-benzaldehyde, stirring at room temperature to react, extracting, drying an organic phase by using anhydrous NaSO4, filtering, and spin-drying to obtain the benzo-alpha-pyran-based Hg < 2 + > fluorescent probe. The preparation method comprises the following steps: taking benzo-alpha-pyran as a raw material, performing silica gel column chromatography separation and purification on an obtained crude product to obtain a compound 1, mixing the compound 1 and 4-phenyl semicarbazide, dissolving in absolute ethyl alcohol, adding glacial acetic acid, performing reflux reaction, and filtering, washing and drying a precipitate to obtain the Hg < 2 + > fluorescent probe based on benzo-alpha-pyran. The invention also provides application of the fluorescent probe for qualitative detection of trace Hg < 2 + > in a water body, and the prepared Hg < 2 + > fluorescent probe has the advantages of high sensitivity, low detection limit, strong selectivity, simple synthesis, short response time and the like, has relatively strong selectivity on Hg < 2 + >, and is suitable for rapid qualitative detection of trace Hg < 2 + > in a water sample.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluorescent probes, and specifically relates to a Hg 2+ Fluorescent probe and its preparation method and application. Background Art

[0002] Mercury ion (Hg 2+ ) is one of the most toxic heavy metal ions in the environment. According to the HSAB (hard and soft acids and bases) theory, Hg 2+ It is a typical soft acid that can react with molecules rich in atoms such as O, N and S. 2+ After entering the body, it is easy to combine with carboxyl, amino and phosphate groups, especially molecules containing sulfhydryl (-SH) or disulfide (-SS-) groups, interfering with the normal metabolism of some proteins and enzymes, thereby causing various diseases such as body dysfunction, memory loss, digestive disorders, dementia, and kidney damage. In order to reduce Hg 2+ The harm caused by pollution requires strict control of the mercury content in water bodies. 2+ Qualitative and quantitative monitoring of content has received widespread attention.

[0003] Currently used for Hg in water 2+ There are many detection methods, such as inductively coupled plasma mass spectrometry, atomic absorption spectroscopy, spectrophotometry, electrochemical method, etc., but the cost of the above-mentioned test instruments is high, the price is expensive, the detection process is relatively complicated, and the sample pretreatment is cumbersome. In contrast, fluorescent probes have the advantages of low cost, high sensitivity, and short response time. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a Hg-based benzo-α-pyran 2+ Fluorescent probe and preparation method and application thereof, the Hg 2+ Fluorescent probes have the advantages of high sensitivity, low detection limit, strong selectivity, simple synthesis, and short response time. 2+ It has strong selectivity and can be used for trace Hg in water. 2+ Rapid qualitative detection.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a Hg 2+ Fluorescent probes based on benzo-α-pyran Hg 2+ The structural formula of the fluorescent probe is

[0006] The present invention also provides the above-mentioned Hg based on benzo-α-pyran 2+ A method for synthesizing a fluorescent probe, the method comprising:

[0007] S1. Dissolve benzoic acid and tetrahydropyrrole in dimethyl sulfoxide, then add cinnamaldehyde and 5-methoxy-2-hydroxy-benzaldehyde in sequence, and stir at room temperature; after the reaction is completed, add distilled water to the system, extract with ethyl acetate, dry the organic phase with anhydrous NaSO4, filter, and spin dry, and separate and purify the obtained crude product by silica gel column chromatography to obtain compound 1; the structural formula of compound 1 is

[0008] S2, the compound 1 obtained in S1 and 4-phenylaminourea are mixed, dissolved in anhydrous ethanol, glacial acetic acid is added, after reflux reaction, the precipitate is filtered, washed, and dried to obtain Hg based on benzo-α-pyran 2+ Fluorescent probes.

[0009] Preferably, the molar ratio of benzoic acid, tetrahydropyrrole, cinnamaldehyde and 5-methoxy-2-hydroxy-benzaldehyde in S1 is 2:2:3:3.

[0010] Preferably, in the silica gel column chromatography separation and purification in S1, petroleum ether:ethyl acetate=15:1 (v / v) is used as the eluent.

[0011] Preferably, the temperature of the reflux reaction in S2 is 80°C.

[0012] Preferably, the molar ratio of compound 1 to 4-phenylaminourea in S2 is 1:1.2.

[0013] The present invention also provides a benzo-α-pyran-based Hg 2+ Application of fluorescent probes, the Hg based on benzo-α-pyran 2+ Fluorescent probes can be used to prepare test strips by solution immersion method for trace Hg in water 2+ Qualitative detection.

[0014] Preferably, the benzo-α-pyran based Hg 2+ The detection limit of the fluorescent probe was 4.09×10 -7 mol / L.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. The present invention prepares a Hg based on benzo-α-pyran 2+ Fluorescent probe, detection limit can reach 4.09×10 - 7 mol / L, with the advantages of good selectivity, high sensitivity and simple structure.

[0017] 2. The raw materials used in the present invention are low in cost, the reaction conditions are mild, the synthesis method is simple and easy, the post-processing steps are simple, the yield is high, and it is suitable for large-scale production.

[0018] 3. The probe involved in the present invention can be made into test paper, which can detect Hg under ultraviolet light. 2+ Perform qualitative testing.

[0019] 4. The fluorescent probe involved in the present invention can selectively detect Hg in the water phase 2+ , and the sensitivity is high, and the rapid detection of trace mercury ions can be achieved by the test paper method, and it has a good application prospect. The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of the preparation of the fluorescent probe CPC according to Example 1 of the present invention.

[0021] Figure 2 is the fluorescent probe CPC of Example 1 of the present invention 1 H NMR spectrum (DMSO-d6, 400 MHz).

[0022] Figure 3 is the fluorescent probe CPC of Example 1 of the present invention 13 C NMR spectrum (DMSO-d6, 101 MHz).

[0023] Figure 4 This is the ESI mass spectrum of the fluorescent probe CPC in Example 1 of the present invention.

[0024] Figure 5 It is the fluorescence emission spectra of the fluorescent probe CPC of Example 2 of the present invention in different solvents.

[0025] Figure 6 It is a fluorescence emission spectrum diagram of the fluorescent probe CPC of Example 2 of the present invention in a mixed solution of EtOH and water in different proportions.

[0026] Figure 7 It is a fluorescence emission spectrum diagram of the fluorescent probe CPC of Example 2 of the present invention in a mixed solution of EtOH and water containing different metal cations.

[0027] Figure 8 The fluorescent probes CPC and CPC+Hg of Example 2 of the present invention are 2+ Fluorescence emission spectra at different pH values.

[0028] Fig. 9 The fluorescent probe CPC of Example 2 of the present invention can identify Hg in other coexisting metal ion solutions.2+ Anti-interference fluorescence emission spectrum.

[0029] Fig.10 The fluorescence of the fluorescent probe CPC in Example 2 of the present invention varies with Hg 2+ Linear fitting curve of concentration change.

[0030] Fig.11 The fluorescent probe CPC of Example 2 of the present invention and Hg in different proportions 2+ Job'sPlot curve.

[0031] Fig.12 It is the response of the CPC test paper of Example 2 of the present invention to different metal cations under 365nm ultraviolet light. DETAILED DESCRIPTION

[0032] Example 1

[0033] The Hg based on benzo-α-pyran in this example 2+ Fluorescent probes based on benzo-α-pyran Hg 2+ The structural formula of the fluorescent probe is

[0034] This embodiment provides the above-mentioned Hg based on benzo-α-pyran 2+ The synthesis method of fluorescent probe is shown in the flowchart Figure 1 As shown, the method is:

[0035] S1. In a 50 mL round-bottom flask, benzoic acid (0.488 g, 4 mmol) and tetrahydropyrrole (0.28 g, 4 mmol) were dissolved in 15 mL dimethyl sulfoxide (DMSO), and then cinnamaldehyde (0.66 g, 6 mmol) and 5-methoxy-2-hydroxy-benzaldehyde (0.912 g, 6 mmol) were added in sequence, and the reaction was stirred at room temperature for 6 h; after the reaction was completed, 30 mL of distilled water was added to the system, and after extraction with 90 mL of ethyl acetate three times, the organic phase was dried over anhydrous NaSO4, and the filtrate was concentrated and dried by rotary evaporator to obtain a crude product, and then petroleum ether: ethyl acetate = 15:1 (v / v) was used as the eluent, and the product was separated and purified by silica gel column chromatography to obtain a light yellow solid substance, i.e., compound 1 (0.89 g, yield 66%); the structural formula of the compound 1 is

[0036] S2. In a 50 mL round-bottom flask, compound 1 (0.789 g, 3 mmol) obtained in S1 and 4-phenylaminourea (0.544 g, 3.6 mmol) were mixed and dissolved in 15 mL of anhydrous ethanol. Five drops of glacial acetic acid were added. After reflux reaction at 80 ° C for 3 h, a large amount of light yellow precipitate was precipitated in the flask. The precipitate was filtered, washed and dried to obtain a light yellow solid substance, i.e., Hg based on benzo-α-pyran. 2+ Fluorescent probe (0.736 g, 72.4%), named as fluorescent probe CPC.

[0037] The nuclear magnetic resonance hydrogen spectrum of the fluorescent probe CPC prepared in this example ( 1 H NMR) Figure 2 The characterization data are as follows: 1 H NMR (400MHz, DMSO-d6) δ10.73(s,1H),8.48(s,1H),7.75(s,1H),7.56-7.54(d,J=8.0Hz,2H),7.43-7.41(d,J=8Hz,2 H),7.31-7.22(m,5H),7.07(s,1H),7.03-6.99(t,J=16Hz,1H),6.86(s,1H),6.73-6.72(d,J=4Hz,3H),3.70(s,3H).

[0038] The carbon NMR spectrum of the fluorescent probe CPC ( 13 C NMR) Figure 3 The characterization data are as follows: 13 C NMR(101MHz,DMSO-d6)δ154.18,153.06,146.66,140.08,139.94,139.21,132.33,129.03,128 .85,128.74,127.63,127.48,123.03,122.94,119.93,117.46,116.35,112.33,74.14,55.83.

[0039] High-resolution mass spectrometry of the fluorescent probe CPC Figure 4 As shown, the characterization data are as follows: HRMS (ESI) calcd.forC 24 H 21 N3O3[M+Na] + 422.1745,found:422.1745.

[0040] Example 2

[0041] This example is a performance test of the fluorescent probe CPC prepared in Example 1.

[0042] (1) Preparation of metal cation stock solution

[0043] The precise concentration is 1×10 -2 mol / L of HgCl2, FeCl3, CeCl3, KCl, CuCl2·2H2O, NaCl, ZnCl2, MgCl2, CrCl3·6H2O, CdCl2, AlCl3·6H2O, NiCl2·6H2O, GdCl3, SnCl2, CoCl2 ·6H2O, YbCl3·xH2O, NdCl3, ScCl3, ZrCl4, SmCl3·6H2O, LiCl, InCl3, HoCl3·6H2O, GaCl3, PTCl3·H2O, LaCl3·H2O, YCl3, MnCl2·4H2O aqueous solution.

[0044] (2) Effects of different polar solvents on the fluorescent probe CPC

[0045] DMF (N,N-dimethylformamide), EA (ethyl acetate), DMSO (dimethyl sulfoxide), PE (petroleum ether), EtOH (ethanol), DCM (dichloromethane), MeOH (methanol) were used as solvents, and the concentration was precisely configured to be 1×10 -4 mol / L fluorescent probe CPC solution. Take 0.3mL of the fluorescent probe solution in different solvents and add it to a four-way quartz cuvette, add 2.7mL of the corresponding solvent, and prepare a test solution with a probe concentration of 10μM. Under the conditions of excitation wavelength of 350nm and voltage of 700V, measure its fluorescence intensity when it is stable. The experimental results are as follows Figure 5 As shown, EtOH was selected as the test solvent because of its low toxicity and high fluorescence intensity.

[0046] (3) Aggregation-induced emission of fluorescent probe CPC

[0047] The concentration is 1×10 -4 0.3 mL of mol / L fluorescent probe CPC solution was added to a four-way quartz cuvette, and the ratio of ethanol and water was adjusted to prepare a test solution with a probe concentration of 10 μM. Under the conditions of excitation wavelength of 350 nm and voltage of 700 V, the fluorescence intensity was measured when it was stable. The experimental results are shown in Figure 2. Figure 6 As shown, the maximum emission wavelength of the probe is around 491 nm (EtOH: water = 3:7), and it exhibits a high fluorescence intensity, so the next series of tests are all carried out under the condition of EtOH: water = 3:7.

[0048] (4) Selective recognition of different metal cations by probe CPC

[0049] Take 2.1mL water and 0.6mL ethanol solution and place them in a four-way quartz cuvette, add 0.3mL fluorescent probe CPC solution, and then add 9μL Hg 2+ , Fe 3+ ,Ce 3+ ,K + ,Cu 2+ ,Na + ,Zn 2+ Mg 2+ ,Cr 3+ ,Cd 2+ ,Al 3+ ,Ni 2+ ,Gd 3+ ,Sn 2+ ,Co 2+ ,Yb 3+ ,Nd 3+ ,Sc 3+ ,Zr 4+ ,Sm 3+ ,Li + ,In 3+ ,Ho 3+ ,Ga 3+ ,PT 3+ ,La 3+ ,Y 3+ ,Mn 2+ The aqueous solution was prepared into a test solution with a probe concentration of 10 μM and an ion concentration of 30 μM. Under the conditions of an excitation wavelength of 350 nm and a voltage of 700 V, the fluorescence intensity at the stable state was measured.

[0050] The experimental results are as follows Figure 7 As shown in the figure, when the fluorescent probe CPC coexists with various metal cations, only Hg 2+ The fluorescence intensity at 491 nm was significantly reduced, indicating that the fluorescent probe CPC was 2+ There is good selectivity.

[0051] (5) Effect of pH on fluorescent probes CPC and CPC+Hg 2+ Impact

[0052] 2.1 mL of water and 0.6 mL of ethanol solution were placed in a four-way quartz cuvette, and 0.3 mL of fluorescent probe CPC solution was added to prepare a test solution with a probe concentration of 10 μM. The solution pH was adjusted to 1-12 by 1 M HCl solution and 1 M NaOH solution. Under the conditions of excitation wavelength of 350 nm and voltage of 660 V, the fluorescence intensity at the stable state was measured.

[0053] The experimental results are as follows Figure 8The probe CPC solution itself has a pH of 7.6, and its fluorescence intensity will gradually increase with the increase of acidity / alkalinity; the same CPC+Hg 2+ The fluorescence intensity of the coexistence system also increases slightly with the increase of acidity / alkalinity.

[0054] (6) Detection of Hg by fluorescent probe CPC 2+ Anti-interference performance

[0055] Take 2.1mL of water and 0.6mL of ethanol solution and place them in a four-way quartz cuvette, add 0.3mL of fluorescent probe CPC solution, and then add 9μL of Fe 3+ ,Ce 3+ ,K + ,Cu 2+ ,Na + ,Zn 2+ Mg 2+ ,Cr 3+ ,Cd 2+ ,Al 3+ ,Ni 2+ ,Gd 3+ ,Sn 2+ ,Co 2+ ,Yb 3+ ,Nd 3+ ,Sc 3+ ,Zr 4+ ,Sm 3+ ,Li + ,In 3+ ,Ho 3+ ,Ga 3+ ,PT 3+ ,La 3+ ,Y 3+ ,Mn 2+ aqueous solution, and then add 9 μL Hg 2+ Aqueous solution, prepared with a probe concentration of 10 μM, an ion concentration of 30 μM, and Hg 2+ The concentration of the test solution is 30 μM. Under the conditions of excitation wavelength 350 nm and voltage 700 V, the fluorescence intensity at the stable state is measured.

[0056] The experimental results are as follows Fig. 9 As shown, Hg 2+ The fluorescence intensity of each mixed system at 491 nm was significantly reduced, indicating that other metal cations would not affect the recognition of Hg by the fluorescent probe CPC. 2+ Cause interference.

[0057] (7) Fluorescent probe CPC for Hg 2+ Sensitivity of detection

[0058] Take 2.1mL of water and 0.6mL of ethanol solution and place them in a four-way quartz cuvette, add 0.3mL of fluorescent probe CPC solution, and prepare a test solution with a probe concentration of 10μM. Then add different concentrations of Hg 2+ Aqueous solution (0–60 μM). Under the conditions of excitation wavelength 350 nm and voltage 700 V, the change in fluorescence intensity was measured.

[0059] The experimental results are as follows Fig.10 As shown, the probe CPC and Hg 2+ It showed a good linear relationship in the range of (0-10μM). After linear fitting, the probe CPC showed a good linear relationship with Hg 2+ Detection standard curve. According to LOD = 3σ / K, the detection limit of the fluorescent probe CPC is 4.09×10 -7 mol / L.

[0060] (8) Fluorescent probe CPC and Hg 2+ The combination mode,

[0061] Maintain CPC and Hg 2+ The total concentration was 10 μM. 2+ The molar ratio of CPC+Hg was configured with different molar ratios. 2+ The solution to be tested. Under the conditions of excitation wavelength 350nm and voltage 700V, the fluorescence intensity at the stable state is measured. The Job's plot curve is confirmed by the fluorescence emission spectrum.

[0062] The experimental results are as follows Fig.11 As shown, a linear fit was performed on the two sets of data, and the intersection point was 0.5, indicating that CPC and Hg 2+ The coordination ratio is 1:1.

[0063] (9) Response of CPC test paper to different metal cations

[0064] The filter paper was immersed in a CPC solution (100 μM) dissolved in anhydrous ethanol for 30 seconds and then naturally dried. This operation was repeated three times to obtain CPC test paper. The prepared CPC test paper was immersed in different metal cation solutions.

[0065] The experimental results are as follows Fig.12 As shown, under 365nm ultraviolet light, only Hg 2+ The test paper after infiltration showed obvious fluorescence quenching, while other metal cations showed no obvious changes, indicating that the prepared CPC test paper can be used for qualitative detection of Hg 2+ .

[0066] In summary, the Hg based on benzo-α-pyran prepared by the present invention 2+Fluorescent probes can be used to prepare test strips by solution immersion method and applied to trace Hg in water 2+ in qualitative testing.

[0067] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A Hg based on benzo-α-pyran 2+ A fluorescent probe, characterized in that The benzo-α-pyran-based Hg 2+ The structural formula of the fluorescent probe is 2. A method for preparing the Hg based on benzo-α-pyran as claimed in claim 1 2+ The method of a fluorescent probe is characterized in that The method is: S1. Dissolve benzoic acid and tetrahydropyrrole in dimethyl sulfoxide, then add cinnamaldehyde and 5-methoxy-2-hydroxy-benzaldehyde in sequence, and stir at room temperature; after the reaction is completed, add distilled water to the system, extract with ethyl acetate, dry the organic phase with anhydrous NaSO4, filter, and spin dry, and separate and purify the obtained crude product by silica gel column chromatography to obtain compound 1; the structural formula of compound 1 is S2, the compound 1 obtained in S1 and 4-phenylaminourea are mixed, dissolved in anhydrous ethanol, glacial acetic acid is added, after reflux reaction, the precipitate is filtered, washed, and dried to obtain Hg based on benzo-α-pyran 2+ Fluorescent probes.

3. The method according to claim 2, characterized in that The molar ratio of benzoic acid, tetrahydropyrrole, cinnamaldehyde and 5-methoxy-2-hydroxy-benzaldehyde in S1 is 2:2:3:

3.

4. The method according to claim 2, characterized in that: In the silica gel column chromatography separation and purification described in S1, petroleum ether and ethyl acetate in a volume ratio of 15:1 were used as eluents.

5. The method according to claim 2, characterized in that: The temperature of the reflux reaction in S2 is 80°C.

6. The method according to claim 2, characterized in that The molar ratio of compound 1 and 4-phenylaminourea in S2 is 1:1.

2.

7. A Hg-based benzo-α-pyran prepared by the method according to any one of claims 2 to 6 2+ The application of fluorescent probe is characterized by: The benzo-α-pyran-based Hg 2+ Fluorescent probes can be used to prepare test strips by solution immersion method for trace Hg in water 2+ Qualitative detection.

8. The use according to claim 7, characterized in that: The benzo-α-pyran-based Hg 2+ The detection limit of the fluorescent probe was 4.09×10 -7 mol / L.

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