An enhanced fluorescent probe that specifically recognizes mercury ions, its synthesis method, and its applications.

Abstract

This invention discloses a method for synthesizing and applying an enhanced fluorescent probe that specifically recognizes mercury ions. The probe is based on the rhodamine structure and modified with a pyridyl isothiocyanate structure, with the molecular formula C0.05. 34 H 35 N6O2S, labeled FS-Hg, is a fluorescent probe that can monitor mercury ions in real time in N,N-dimethylformamide solution. It only causes a visible color change (from colorless to bright pink) and new spectral bands upon recognition of mercury ions. The probe also causes a sharp increase in absorbance at 568 nm and a sharp increase in fluorescence intensity at 594 nm upon mercury ion recognition. The mercury ion recognition process exhibits concentration dependence, extremely high sensitivity, good selectivity, and stable sensing characteristics. This probe can efficiently detect mercury ion concentration in aquatic products, which is of great significance for on-site detection and large-scale screening of heavy metals in food safety.

Description

Technical Field

[0001] This invention belongs to the field of organic small molecule fluorescent probe technology, specifically relating to an enhanced fluorescent probe that specifically recognizes mercury ions, its synthesis method, and its application. Background Technology

[0002] With rapid industrial development, heavy metal pollution has become one of the most serious environmental pollution problems globally, and heavy metal contamination in food has become a significant factor affecting food safety. Mercury (Hg) is one of the most toxic and widely distributed heavy metals in nature. It is highly toxic; even trace amounts can cause serious damage to human health and the ecological environment. Mercury mainly exists in organisms in the form of methylmercury, accumulating in the human body through biotransformation and the food chain. Mercury in the body is difficult to degrade, thus inducing various serious diseases. Long-term intake of food containing mercury ions can lead to nerve damage, kidney failure, developmental delays, DNA damage, brain damage, and cardiovascular system disruption. More and more countries and international organizations are imposing strict regulations on the mercury content in food. Therefore, achieving rapid, accurate, efficient, and safe monitoring of mercury in food is of great significance for food safety.

[0003] Currently, techniques successfully used for mercury ion detection include spectrophotometry, atomic absorption spectrometry, surface-enhanced Raman scattering, high-performance liquid chromatography (HPLC), and inductively coupled plasma atomic emission spectrometry (ICP-AES). However, these methods suffer from drawbacks such as complex operation, expensive equipment, long processing times, and the need for trained personnel. In recent years, with the development of physical optics, small-molecule fluorescent probe-based analysis has attracted widespread attention. This method offers advantages such as high selectivity, high efficiency, high sensitivity, and real-time online monitoring, and has been widely applied in food analysis and detection. However, these fluorescent probes suffer from drawbacks such as weak specificity, long response times, and insufficient anti-interference capabilities, limiting their development in practical applications.

[0004] The conjugated structure of the spironolactam ring in rhodamine often induces chelation upon recognizing metal ions, causing changes in fluorescence switching, and is therefore frequently used in the synthesis of "off-on" fluorescent probes. Based on this, this invention designs and synthesizes an enhanced fluorescent probe that specifically recognizes mercury ions, enabling real-time monitoring of mercury ions in aquatic products with visualization, low detection limits, and high sensitivity. Summary of the Invention

[0005] The purpose of this invention is to provide a method for synthesizing and applying an enhanced fluorescent probe that specifically recognizes mercury ions.

[0006] The technical solution of the present invention is as follows:

[0007] This invention provides an enhanced fluorescent probe that specifically recognizes mercury ions, with the molecular formula C. 34 H 35 N6O2S, labeled FS-Hg, has the chemical structural formula shown in (I):

[0008]

[0009] This invention provides a method for synthesizing an enhanced fluorescent probe that specifically recognizes mercury ions, comprising the following steps:

[0010] (1) Rhodamine B and hydrazine hydrate were dissolved in anhydrous ethanol solution and reacted by heating. The gray solid, compound 1, was obtained by separation and purification. The reaction process is as follows:

[0011]

[0012] (2) Compound 1 and 3-pyridyl isothiocyanate were dissolved in N,N-dimethylformamide solution and reacted at room temperature. The resulting dark purple solid, which was the fluorescent probe FS-Hg, was obtained by separation and purification. The reaction process is as follows:

[0013]

[0014] Furthermore, in step (1), the molar ratio of rhodamine B to hydrated hydrazine is 1:10.

[0015] Furthermore, in step (1), the heating temperature is 90°C and the heating time is 8-12 hours.

[0016] Furthermore, in step (1), the separation and purification process adopts column chromatography, and the eluent is a mixture of petroleum ether and ethyl acetate with a volume ratio of 5-3:2.

[0017] Furthermore, in step (2), the molar ratio of compound 1 to 3-pyridyl isothiocyanate is 1:1.

[0018] Furthermore, in step (2), the reaction time is 8-12 hours.

[0019] Furthermore, in step (2), the separation and purification process adopts column chromatography separation, and the chromatographic eluent is a dichloromethane / methanol mixed solution with a volume ratio of 80-50:1.

[0020] This invention provides an enhanced fluorescent probe that specifically identifies mercury ions for use in the detection of aquatic products.

[0021] Furthermore, this fluorescent probe can monitor mercury ions in N,N-dimethylformamide solution in real time, and only after recognizing mercury ions will it cause a visible color change (from colorless to bright pink) and new spectral bands.

[0022] Furthermore, this fluorescent probe only causes a sharp increase in the absorption value of the ultraviolet absorption spectrum at 568 nm and a sharp increase in the fluorescence intensity of the fluorescence spectrum at 594 nm after recognizing mercury ions, thus activating strong fluorescence.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) This invention designs and synthesizes an enhanced fluorescent probe FS-Hg that specifically recognizes mercury ions. In N,N-dimethylformamide solution, this fluorescent probe induces a visible colorimetric response (from colorless to bright pink) only after specifically recognizing mercury ions, and activates strong fluorescence, generating new spectral bands. It exhibits extremely high sensitivity, good selectivity, and stable light energy characteristics during the sensing process.

[0025] (2) The synthesis method of the fluorescent probe FS-Hg in this invention is simple, with considerable yield, low cost and simple operation. Moreover, it is an open fluorescent probe, which can avoid background interference caused by objective factors and presents high accuracy. It can be applied to the safety assessment of mercury pollution in food and has good development prospects in the field of food safety.

[0026] (3) The present invention designs and synthesizes an enhanced fluorescent probe FS-Hg that specifically recognizes mercury ions. The process of recognizing mercury ions by the fluorescent probe also shows concentration dependence, extremely high sensitivity, good selectivity and stable sensing characteristics.

[0027] (4) Invention This invention designs and synthesizes an enhanced fluorescent probe FS-Hg that specifically recognizes mercury ions. The fluorescent probe performs well in actual aquatic product testing, and the spiked recovery experiment results are good, with a recovery rate of 108.4%-113.2%.

[0028] Figure Labels

[0029] Figure 1 The above is the proton NMR spectrum of the fluorescent probe FS-Hg synthesized in Example 1 of this invention;

[0030] Figure 2 The image shows the carbon NMR spectrum of the fluorescent probe FS-Hg synthesized in Example 1 of this invention.

[0031] Figure 3The fluorescence spectra of the fluorescent probe FS-Hg synthesized in Example 1 of this invention in response to mercury ions in solvents with different polarities and dielectric constants are shown in Figure A (fluorescence spectrum, B is fluorescence intensity variation graph).

[0032] Figure 4 The fluorescence spectra of the fluorescent probe FS-Hg synthesized in Example 1 of this invention in N,N-dimethylformamide solution with different ions are shown in the graphs (A is the fluorescence spectrum, B is the fluorescence intensity graph, and C is the fluorescence intensity change factor graph).

[0033] Figure 5 The UV-Vis spectra of the fluorescent probe FS-Hg synthesized in Example 1 of this invention in N,N-dimethylformamide solution with different ions are shown in the graphs (A is the UV spectrum, B is the absorbance graph, and C is the absorbance change factor graph).

[0034] Figure 6 The fluorescence spectrum of the fluorescent probe FS-Hg synthesized in Example 1 of this invention in N,N-dimethylformamide solution in response to mercury ion concentration is shown in the graph (A is the fluorescence spectrum, B is the fluorescence intensity graph, and C is the linearity analysis graph).

[0035] Figure 7 The UV-Vis spectrum of the fluorescent probe FS-Hg synthesized in Example 1 of this invention in N,N-dimethylformamide solution in response to mercury ion concentration is shown in the graph (A is the UV spectrum, B is the absorbance graph, and C is the linearity graph).

[0036] Figure 8 This is a stability response diagram of the fluorescent probe FS-Hg synthesized in Example 1 of the present invention in N,N-dimethylformamide solution during the mercury ion sensing process.

[0037] Figure 9 The fluorescence spectrum of the fluorescent probe FS-Hg synthesized in Example 1 of this invention in N,N-dimethylformamide solution for detecting residual mercury content in actual samples is shown in the graph (A is the fluorescence spectrum, B is the fluorescence intensity graph, and C is the linearity analysis graph). Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and preferred embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0039] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0040] Unless otherwise specified, the experimental methods described in the following examples are conventional methods.

[0041] The drying solvents used in the reaction were all dried using molecular sieve type 4A (sodium-A type molecular sieve) or molecular sieve type 3A (potassium-A type molecular sieve);

[0042] Argon was used as the protective gas in all inert atmospheres used in the reaction.

[0043] 1 The H-s spectra were recorded on a JEOL ECZ600S (600MHz) spectrometer using CDCl3 as the solvent.

[0044] Based on internal TMS (trimethylsilane) reference data, a front field chemical shift of one part per million was reported;

[0045] The coupling constant (J) is expressed in Hertz (Hz), and the spin multiple states are expressed in s (singlet state), d (doublet state), t (triplet state), and m (multiplex state);

[0046] Solid-phase column chromatography separation was performed using thick-walled glass columns and silica gel (300-400 mesh).

[0047] Thin-layer chromatography (TLC) was performed using commercially available 0.25 mm silica gel plates, and the results were displayed under ultraviolet light.

[0048] The ultraviolet absorption spectrum was obtained using a Shimadzu UV-1900 UV-Vis-NIR spectrophotometer.

[0049] Fluorescence spectra were obtained using a Spectrofluorometer FS5 fluorescence spectrometer and determined.

[0050] The relative molecular mass was recorded using a ThermoFisher high performance liquid chromatography-mass spectrometry system.

[0051] Samples were processed using a CEMmars6 high-throughput microwave digester.

[0052] Example 1

[0053] This embodiment provides an enhanced fluorescent probe that specifically recognizes mercury ions, and its synthesis method includes the following steps:

[0054] (1) Rhodamine B (888.48 mg, 2.00 mM) and hydrazine hydrate (640.80 mg, 20 mM) were dissolved in anhydrous ethanol solution (200 mL). The mixture was heated under reflux at 85 °C and stirred for 12 h. The solvent was removed by rotary evaporation under reduced pressure. The gray solid, compound 1, was obtained by separation and purification using a petroleum ether / ethyl acetate mixture with a volume ratio of 3:2. The yield was 415.88 mg, and the yield was 45.60%. The reaction process is as follows:

[0055]

[0056] (2) Compound 1 (228.13 mg, 0.50 mM) and 3-pyridyl isothiocyanate (68.01 mg, 0.50 mM) were dissolved in N,N-dimethylformamide solution (10 mL). The mixture was stirred at room temperature for 12 h, and the solvent was removed by rotary evaporation under reduced pressure. The solution was purified by separation with a 50:1 dichloromethane / methanol mixture to obtain a dark purple solid, which was the probe FS-Hg. The yield was 255.90 mg, and the yield was 86.6%. The reaction process is as follows:

[0057]

[0058] The sample obtained in Example 1 was subjected to proton and carbon NMR spectroscopy analysis, and the resulting spectra are shown in the attached figure. Figure 1 , 2 As shown.

[0059] Example 2

[0060] (1) Rhodamine B (888.48 mg, 2.00 mM) and hydrazine hydrate (640.80 mg, 20 mM) were dissolved in anhydrous ethanol solution (20 mL). The mixture was heated under reflux at 90 °C and stirred for 10 h. The solvent was removed by rotary evaporation under reduced pressure. The gray solid was obtained by separation and purification using a petroleum ether / ethyl acetate mixed solution with a volume ratio of 5:2. This solid was compound 1.

[0061] (2) Compound 1 (228.13 mg, 0.50 mM) and 3-pyridyl isothiocyanate (68.01 mg, 0.50 mM) were dissolved in N,N-dimethylformamide solution (10 mL). The mixture was stirred at room temperature for 8 h. The solvent was removed by rotary evaporation under reduced pressure. The dark purple solid was obtained by separation and purification using a dichloromethane / methanol mixed solution with a volume ratio of 65:1. This solid was the probe FS-Hg.

[0062] Example 3

[0063] (1) Rhodamine B (888.48 mg, 2.00 mM) and hydrazine hydrate (640.80 mg, 20 mM) were dissolved in anhydrous ethanol solution (20 mL). The mixture was heated under reflux at 110 °C for 8 h and the solvent was removed by rotary evaporation under reduced pressure. The gray solid was obtained by separation and purification using a petroleum ether / ethyl acetate mixed solution with a volume ratio of 4:2, which was compound 1.

[0064] (2) Compound 1 (228.13 mg, 0.50 mM) and 3-pyridyl isothiocyanate (68.01 mg, 0.50 mM) were dissolved in N,N-dimethylformamide solution (10 mL). The mixture was stirred at room temperature for 10 h. The solvent was removed by rotary evaporation under reduced pressure. The dark purple solid was obtained by separation and purification using a dichloromethane / methanol mixed solution with a volume ratio of 80:1. This solid was the probe FS-Hg.

[0065] Example 4

[0066] This embodiment utilizes the enhanced fluorescent probe that specifically recognizes mercury ions from Example 1 to study its spectral properties, including the following steps:

[0067] (1) Fluorescence spectra of the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions in Example 1, with 20 eq of mercury ions in solvents of different polarities and dielectric constants:

[0068] (2) Fourteen solvents with different polarities and dielectric constants were screened based on solvent polarity and dielectric constant: tetrahydrofuran, acetonitrile, N,N-dimethylformamide, water, PBS buffer (10mM, pH=7.1), PBS buffer / acetonitrile mixture (3 / 7, v / v, 10mM, pH=7.1), PBS buffer / acetonitrile mixture (7 / 3, v / v, 10mM, pH=7.1), HEPES buffer (10mM, pH=7.2), HEPES buffer / acetonitrile mixture (3 / 7, v / v, 10mM, pH=7.2), HEPES buffer / acetonitrile mixture (7 / 3, v / v, 10mM, pH=7.2), methanol, methanol / water mixture (3 / 7, v / v), methanol / water mixture (7 / 3, v / v), and ethanol;

[0069] (3) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution and placed in the 14 solvents described in step (1) to dilute to 10 μM probe buffer solution. The fluorescence spectrum after the reaction with 200 μM mercury ions was measured, and the fluorescence intensity change at 594 nm was analyzed. The conditions of the fluorescence spectrometer were: λex = 562 nm, Step: 1.00 nm, Dwell: 0.1 s, Repeats: 1, slit width: 2.

[0070] like Figure 3As shown in Figure A, the probe can recognize mercury ions in all solvents except tetrahydrofuran and PBS buffer, exhibiting the same fluorescence change characteristics and activating intense fluorescence. By comparing the fold change in fluorescence intensity at the emission wavelength of 594 nm, the change was found to be most significant in N,N-dimethylformamide solution. Therefore, N,N-dimethylformamide solvent can be selected as a good medium for the fluorescent probe FS-Hg to recognize mercury ions.

[0071] Example 5

[0072] This embodiment utilizes the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions as described in Example 1, to perform fluorescence spectral analysis with 20 eq of other different ions in N,N-dimethylformamide solvent. The steps include:

[0073] (1) 32 other different ions were screened out: sodium fluoride, sodium bromide, sodium iodide, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium bisulfite, sodium sulfate, sodium bicarbonate, sodium carbonate, potassium chloride, lithium hydroxide monohydrate, sodium chloride, ammonium chloride, nickel chloride, cesium carbonate, zinc chloride, calcium chloride, magnesium chloride, manganese chloride, copper sulfate pentahydrate, cerium trichloride pentahydrate, aluminum chloride, cobalt chloride, tin trichloride, cadmium sulfate, chromium trichloride hexahydrate, ferrous chloride tetrahydrate, anhydrous ferric chloride, and lead chloride;

[0074] (2) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, and diluted to 10 μM probe buffer solution. The fluorescence spectrum after the reaction of 200 μM different ions was measured, and the fluorescence intensity change at 594 nm was analyzed. The fluorescence spectrometer conditions were: λex = 562 nm, Step: 1.00 nm, Dwell: 0.1 s, Repeats: 1, slit width: 2.

[0075] like Figure 4 As shown in AC, the probe in N,N-dimethylformamide solvent only activates intense fluorescence after recognizing mercury ions, with the fluorescence intensity changing by more than three hundred times at the emission wavelength of 594 nm.

[0076] Example 6

[0077] This embodiment utilizes the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions as described in Example 1, to perform ultraviolet spectral analysis with 20 eq of other different ions in N,N-dimethylformamide solvent. The steps include:

[0078] (1) 32 other different ions were screened out: sodium fluoride, sodium bromide, sodium iodide, disodium hydrogen phosphate, sodium dihydrogen phosphate, sodium bisulfite, sodium sulfate, sodium bicarbonate, sodium carbonate, potassium chloride, lithium hydroxide monohydrate, sodium chloride, ammonium chloride, nickel chloride, cesium carbonate, zinc chloride, calcium chloride, magnesium chloride, manganese chloride, copper sulfate pentahydrate, cerium trichloride pentahydrate, aluminum chloride, cobalt chloride, tin trichloride, cadmium sulfate, chromium trichloride hexahydrate, ferrous chloride tetrahydrate, anhydrous ferric chloride, and lead chloride;

[0079] (2) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, diluted to 10 μM probe buffer solution, and the ultraviolet spectrum after the reaction of 200 μM different ions was measured. The change of its absorbance at 568 nm was analyzed.

[0080] like Figure 5 As shown in AC, when the probe is in N,N-dimethylformamide solvent, after recognizing mercury ions, the solution changes from colorless to bright pink, with an absorbance change of over 900 times at 568 nm. After recognizing copper ions, the solution changes from colorless to deep purple, with an absorbance change of over 700 times at 568 nm.

[0081] Example 7

[0082] This embodiment utilizes the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions as described in Example 1, to perform fluorescence spectral analysis with different concentrations of mercury ions in N,N-dimethylformamide solvent. The steps include:

[0083] (1) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, and diluted to a 10 μM probe buffer solution. Fluorescence spectra after the addition of different concentrations of mercury ions (0-200 μM) were measured, and the change in fluorescence intensity at 594 nm was analyzed. The fluorescence spectrometer conditions were: λex = 562 nm, Step: 1.00 nm, Dwell: 0.1 s, Repeats: 1, slit width: 2.

[0084] like Figure 6 As shown in AC, the fluorescence intensity of the fluorescent probe at 594 nm gradually increases with increasing mercury ion concentration, until it stops changing with further concentration increases after 65 μM. Furthermore, the fluorescent probe exhibits good linearity within the 0-10 μM mercury ion concentration range, with a correlation coefficient R0. 2 =0.999, detection limit is 0.14μM.

[0085] Example 8

[0086] This embodiment utilizes the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions as described in Example 1, to perform ultraviolet spectral analysis of mercury ions at different concentrations in N,N-dimethylformamide solvent. The steps include the following:

[0087] (1) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, and diluted to 10 μM probe buffer solution. The ultraviolet spectra after the reaction with different concentrations of mercury ions (0-200 μM) were measured, and the changes in its absorbance at 568 nm were analyzed.

[0088] like Figure 7 As shown in AC, the absorbance of the fluorescent probe at 568 nm gradually increases with increasing mercury ion concentration, until after 100 μM, when the fluorescence intensity no longer changes with increasing concentration. Furthermore, within the mercury ion concentration range of 0-30 μM, the fluorescent probe exhibits a good linear relationship, with a correlation coefficient R0. 2 =0.999, therefore the fluorescent probe FS-Hg can be used for qualitative and quantitative detection of mercury ions.

[0089] Example 9

[0090] This embodiment utilizes the fluorescence spectroscopy test of the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions, in N,N-dimethylformamide solvent to study the stability of mercury ions with different concentrations. The steps include:

[0091] (1) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, and diluted to 10 μM probe buffer solution. The fluorescence spectra after the reaction with different concentrations of mercury ions (10, 65 μM) were measured, and the fluorescence intensity change at 594 nm was analyzed. The conditions of the fluorescence spectrometer were: λex = 562 nm, Step: 1.00 nm, Dwell: 0.1 s, Repeats: 1, slit width: 2.

[0092] like Figure 8 As shown, the fluorescence intensity of the fluorescent probe at 594 nm remains basically stable as the response time gradually increases, thus the optical performance of the fluorescent probe FS-Hg is stable.

[0093] Example 10

[0094] This embodiment utilizes the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions as described in Example 1, to detect the residual mercury content in an actual sample in N,N-dimethylformamide solvent. The steps include the following:

[0095] (1) The actual sample was pretreated according to the microwave digestion method in the national standard GB5009.268-2016 to obtain the test solution;

[0096] (2) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, and diluted to 10 μM probe buffer solution. The fluorescence spectra after adding different volumes (0-20 μL) of the test solution were measured, and the fluorescence intensity change at 594 nm was analyzed. The fluorescence spectrometer conditions were: λex = 562 nm, Step: 1.00 nm, Dwell: 0.1 s, Repeats: 1, slit width: 2.

[0097] like Figure 9 As shown in AC, the fluorescence intensity of the fluorescent probe at 594 nm gradually increases with the increase of the test solution, and the fluorescent probe exhibits a good linear relationship in the volume range of 4-10 μL, with a correlation coefficient R. 2 =0.999, the actual residual mercury content of the sample was measured to be 99.1324±0.1540μg / kg.

[0098] Example 11

[0099] This embodiment utilizes the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions as described in Example 1, to perform spiked recovery detection of residual mercury content in actual samples in N,N-dimethylformamide solvent. The steps include the following:

[0100] (1) The actual sample was pretreated according to the microwave digestion method in the national standard GB5009.268-2016 to obtain the test solution;

[0101] (2) The fluorescent probe FS-Hg obtained in Example 1 was dissolved in dimethyl sulfoxide solution, placed in N,N-dimethylformamide solvent, diluted to 10 μM probe buffer solution, and 8 μL of the test solution was added. The fluorescence spectrum after the reaction with different mercury concentrations was measured, and the fluorescence intensity change at 594 nm was analyzed. The conditions of the fluorescence spectrometer were: λex = 562 nm, Step: 1.00 nm, Dwell: 0.1 s, Repeats: 1, slit width: 2.

[0102] (3) Substitute the obtained fluorescence intensity at 594 nm into... Figure 6 The mercury content was calculated from the obtained standard curve, and the spike recovery rate was calculated according to the spike recovery formula: P(recovery rate) = (spiked sample amount - measured sample amount) / spike amount.

[0103] The results are shown in Table 1. The average recovery rates of the spiked experiments were all within the good range, which indicates that the enhanced fluorescent probe FS-Hg, which specifically recognizes mercury ions, can accurately determine the residual mercury content in actual samples in N,N-dimethylformamide solvent.

[0104] Table 1

[0105]

[0106] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An enhanced fluorescent probe which specifically recognizes mercury ions, characterized by, The molecular formula of C 34 H 35 N6O2S, labeled as FS-Hg, and the chemical structure is shown as (I): （I）。 2. The method for synthesizing the enhanced fluorescent probe specifically recognizing mercury ion according to claim 1, characterized in that, The method comprises the following steps: (1) dissolving rhodamine B and hydrazine hydrate in anhydrous ethanol solution in a molar ratio of 1:10, heating and reacting, and obtaining a gray solid through separation and purification, which is compound 1, and the structural formula is shown as (II); (II); (2) dissolving compound 1 and 3-pyridyl isothiocyanate in N, N-dimethylformamide solution, reacting at room temperature, and obtaining a dark purple solid through separation and purification, which is the fluorescent probe FS-Hg.

3. The method for synthesizing an enhanced fluorescent probe for specifically recognizing mercury ions as described in claim 2, characterized in that, In the step (1), the reaction temperature of the heating and reacting is 85-110 DEG C, and the heating time is 8-12 h.

4. The method for synthesizing an enhanced fluorescent probe for specifically recognizing mercury ions as described in claim 2, characterized in that, In the step (1), the separation and purification process adopts column chromatography separation, and the chromatography eluent is a petroleum ether / ethyl acetate mixed solution, and the volume ratio of the two is 5-3:

2.

5. The method for synthesizing an enhanced fluorescent probe that specifically recognizes mercury ions as described in claim 2, characterized in that, In the step (2), the molar ratio of compound 1 to 3-pyridyl isothiocyanate added is 1:

1.

6. The method for synthesizing an enhanced fluorescent probe for specific recognition of mercury ions as described in claim 2, characterized in that, In the step (2), the reaction time at room temperature is 8-12 h.

7. The method for synthesizing an enhanced fluorescent probe for specific recognition of mercury ions as described in claim 2, characterized in that, In the step (2), the separation and purification process adopts column chromatography separation, and the chromatography eluent is a dichloromethane / methanol mixed solution, and the volume ratio of the two is 80-50:

1.

8. The application of the enhanced fluorescent probe for specifically recognizing mercury ions in water product detection according to claim 1.

9. The use of the enhanced fluorescent probe capable of specifically recognizing mercury ions according to claim 8 in the detection of aquatic products, characterized in that, When mercury ions exist in the environment, the fluorescent probe FS-Hg has a complexation reaction with the mercury ions, and obvious color change and new spectral bands are generated.

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