Preparation method and detection and analysis method of a fluorescent probe for identifying D-amino mannose

Abstract

The application discloses a preparation method and a detection analysis method of a fluorescent probe for identifying D-amino mannose, and belongs to the technical field of chiral fluorescence detection. (S)-2,2'-bis(methoxymethoxy)-1,1'-binaphthalene ((S)-6), (S)-2,2'-bis(methoxymethoxy)-[1,1'-binaphthalene]-3,3'-diformyl ((S)-7), (S)-2,2'-dihydroxy-[1,1'-binaphthalene]-3,3'-diformyl ((S)-8) are prepared in sequence according to steps, and finally 8,9,11,12,14,15-hexahydrodibenzo[2,1-k:1',2'-m][1,4,7,10]tetraoxacyclotetradecane-6,17-diformyl ((S)-L8) is synthesized, that is, the fluorescent probe (S)-L8. The fluorescent probe (S)-L8 prepared by the application has high selectivity and high sensitivity for D-ManN, the minimum limited detection concentration is as low as 0.02 mM, and is not interfered by other amino sugars, amino acids or sugars.

Description

Technical Field

[0001] This invention belongs to the field of chiral fluorescence detection technology, specifically relating to a method for preparing and detecting a fluorescent probe for recognizing D-aminomannose. Background Technology

[0002] Amino sugars are derivatives formed by replacing the hydroxyl groups with amino groups in sugar molecules. They are widely found in biological macromolecules such as hyaluronic acid, chondroitin sulfate, and peptidoglycan. Common amino sugars in nature include D-glucosamine (D-GluN), D-galactosamine (D-GalN), and D-mannose (D-ManN). D-ManN is a key signaling molecule for nitrogen fixation in the symbiotic relationship between rhizobia and leguminous plants in soil, and it is also a component of the cell walls of soil microorganisms. Its content can reflect the structure of soil microbial communities and the source of organic matter. Therefore, the high sensitivity and high selectivity of D-ManN detection has important application value.

[0003] While commonly used detection methods such as gas chromatography and high-performance liquid chromatography are mature, they are complex to operate, require expensive equipment, and result in high detection costs. Fluorescence detection methods offer advantages such as high sensitivity and ease of operation, making them ideal for high-throughput detection of analytes. However, due to the structural similarity of D-galactosamine, D-glucosamine, and D-mannose, differing only in spatial configuration, the specific recognition of D-ManN is extremely challenging. Therefore, developing a method for specific fluorescence recognition of D-mannose is of great significance. While commonly used detection methods such as gas chromatography and high-performance liquid chromatography are mature, they are complex to operate, require expensive equipment, and result in high detection costs. Fluorescence detection methods offer advantages such as high sensitivity and ease of operation, making them ideal for high-throughput detection of analytes. However, due to the structural similarity of D-galactosamine, D-glucosamine, and D-mannose, differing only in spatial configuration, the specific recognition of D-ManN presents a significant challenge. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for preparing and detecting a fluorescent probe for recognizing D-aminomannose, which achieves specific and ratiometric fluorescence recognition of D-ManN and has been successfully applied to the detection of D-ManN content in soil.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a method for preparing a fluorescent probe for recognizing D-aminomannose, comprising the following steps: S1. Weigh (S)-binaphthol and sodium hydride, dissolve them separately in ultra-dry tetrahydrofuran, mix the two solutions at 0℃, react for 2 hours, restore to room temperature and continue the reaction, cool to 0℃ after 2 hours and add bromomethyl methyl ether, then restore to room temperature and react again. Then, under ice-water bath conditions, add ultrapure water to quench the reaction, extract with ethyl acetate and combine the organic phases, dry with anhydrous sodium sulfate, and rotary evaporate to obtain a pale yellow solid crude product. Recrystallize and purify to obtain white intermediate one, which is (S)-2,2'-bis(methoxymethoxy)-1,1'-binaphthol ((S)-6); S2. Weigh out white intermediate one, dissolve it in ultra-dry tetrahydrofuran and cool it to -78°C. Then add n-butyllithium to restore the reaction to room temperature. After the solution becomes turbid, cool the solution to 0°C and add ultra-dry N,N-dimethylformamide. After restoring the reaction to room temperature for 3 hours, add saturated ammonium chloride solution to quench the reaction under ice-water bath conditions. Then extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and rotary evaporate to obtain a yellow solid crude product. Purify by column chromatography and dry under vacuum to obtain intermediate two, which is (S)-2,2'-bis(methoxymethoxy)-[1,1'-binaphthyl]-3,3'-dicarboxaldehyde ((S)-7). S3. Weigh intermediate two and dissolve it in a mixed solvent of anhydrous ethanol and dichloromethane. After mixing evenly, add HCl. After the reaction is complete, add pure water and NaHCO3 to quench the reaction. Extract with ethyl acetate, mix the organic phase, dry with anhydrous sodium sulfate, and vacuum distill to remove the solvent to obtain intermediate three. Intermediate three is (S)-2,2'-dihydroxy-[1,1'-binaphthyl]-3,3'-dicarboxaldehyde ((S)-8). S4. Weigh the intermediate tris(t)-fluorinated cesium fluoride and xylene sulfonate into two-necked flasks, evacuate and purge with nitrogen multiple times, add anhydrous acetonitrile to fully dissolve the raw materials, heat to reflux at 65°C until the reaction is complete, then return to room temperature, extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and purify by column chromatography to obtain 8,9,11,12,14,15-hexahydrodinaphthalene[2,1-k:1',2'-m][1,4,7,10]tetraoxanetetradecane-6,17-dicarboxaldehyde ((S)-L8), which is the fluorescent probe (S)-L8.

[0006] Further, in step S1, the equivalent ratio of (S)-binaphthol, sodium hydride, and bromomethyl methyl ether is 1:6:3.

[0007] Further, in step S2, the ratio of n-butyllithium to N,N-dimethylformamide is 1:1, and the equivalent of n-butyllithium is 2.5; the eluent used in silica gel column purification consists of petroleum ether and ethyl acetate in a volume ratio of 10:1.

[0008] Furthermore, in step S3, the volume ratio of anhydrous ethanol to dichloromethane is 1:1, and the amount of HCl is 1.5 equivalents.

[0009] Furthermore, relative to 1 equivalent of (S)-L8, cesium fluoride is 5 equivalents; xylene sulfonate is 1.2 equivalents; and the eluent used for silica gel column purification consists of petroleum ether and ethyl acetate in a volume ratio of 10:1.

[0010] Furthermore, a detection and analysis method for identifying D-aminomannose includes the following steps: P1. Dissolve the fluorescent probe (S)-L8 in dimethyl sulfoxide to obtain the first solution; P2. Dissolve aminoglycoside hydrochloride in ultrapure water, and add NaHCO3 relative to aminoglycoside hydrochloride to obtain a second solution of 88 mM. P3. Take a portion of the solution from the first solution and the second solution, and add them to another sample bottle; P4. Add methanol to the sample vial, mix well and react. P5. After the reaction is complete, dilute the solution to volume with methanol to prepare the third solution. P6. The third solution is placed as the sample in a fluorescence spectrometer. The sample is detected using a light source with a fixed excitation wavelength of 285 nm. Based on the ratiometric detection effect exhibited by the increase in fluorescence intensity at 368 nm and the quenching of fluorescence intensity at 488 nm, specific and selective fluorescence recognition of D-ManN is achieved. Furthermore, during the reaction, ratiometric fluorescence analysis of D-ManN was achieved by detecting the changes in fluorescence intensity at 368 nm and 488 nm.

[0011] Furthermore, during fluorescence detection using the fluorescent probe (S)-8, fluorescence detection was performed at 368 nm and 488 nm, with an excitation wavelength of 285 nm.

[0012] The beneficial effects of this invention are as follows: 1. This invention provides a chiral fluorescent probe (S)-L8 with a short synthetic route and simple operation. This probe exhibits specificity and selectivity for D-ManN, unaffected by other amino sugars, chiral amino acids, or chiral sugars, and can be applied to the rapid fluorescence detection of D-ManN in various soil extracts. Specific and ratiometric detection of D-ManN in complex matrices is achieved by varying the fluorescence intensity at 368 nm and 488 nm under 285 nm excitation.

[0013] 2. The fluorescent probe (S)-L8 prepared by this invention has high selectivity and high sensitivity to D-ManN, with a minimum finite detection concentration as low as 0.02 mM; it is not affected by other amino sugars, amino acids or sugars.

[0014] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0015] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 The molecular structure diagram of the fluorescent probe (S)-L8 prepared in this invention is shown. Figure 2 The hydrogen nuclear magnetic resonance spectrum of the fluorescent probe (S)-L8 prepared in this invention; Figure 3 The carbon NMR spectrum of the fluorescent probe (S)-L8 prepared in this invention; Figure 4 The graph shows the change in fluorescence intensity of the fluorescent probe (S)-L8 prepared in this invention after interacting with different chiral analytes. Figure 5 a is a graph showing the effect of reaction time on the fluorescent probe (S)-L8's fluorescent recognition of D-GalN; Figure 5 b is a graph showing the effect of reaction time on the fluorescent probe (S)-L8's fluorescent recognition of D-GluN; Figure 5 c is a graph showing the effect of reaction time on the fluorescence recognition of D-ManN by the fluorescent probe (S)-L8 in this invention; Figure 5 d is a graph showing the changes in fluorescence recognition of three D-amino sugars by the fluorescent probe (S)-L8 prepared in this invention; Figure 6 a is a graph showing the response of the fluorescent probe (S)-L8 prepared in this invention to different concentrations of D-GalN; Figure 6 b is a graph showing the response of the fluorescent probe (S)-L8 prepared in this invention to different concentrations of D-GluN; Figure 6 c is a graph showing the response of the fluorescent probe (S)-L8 prepared in this invention to different concentrations of D-ManN; Figure 6 d is a graph showing the concentration changes of the fluorescent probe (S)-L8 of this invention when it fluorescently recognizes three D-amino sugars; Figure 7 The image shows the recognition effect of the fluorescent probe (S)-L8 prepared in this invention on D-ManN in different soils. Figure 8The image shows the analysis of D-ManN content in soil extract using the fluorescent probe (S)-L8 prepared in this invention. Figure 9 This is a graph showing the analysis of D-ManN content in soil extract by the fluorescent probe (S)-L8 in an embodiment of the present invention. Detailed Implementation

[0016] like Figures 1-9 As shown, this invention discloses a method for preparing and detecting a fluorescent probe for recognizing D-aminomannose.

[0017] Example 1 A method for preparing a fluorescent probe for detecting D-aminomannose: S1. Weigh (S)-binaphthol (1 eq) and sodium hydride (6 eq) in an equivalent ratio and dissolve them in 50 ml of ultra-dry tetrahydrofuran. Mix the two solutions at 0 °C and react for 2 h. Then, restore the reaction temperature to room temperature and continue the reaction for another 2 h. Then, cool the reaction system to 0 °C and slowly add bromomethyl methyl ether (4 eq). Then, restore the reaction temperature to room temperature and quench the reaction with ultrapure water under ice-water bath conditions. Extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and rotary evaporate to obtain a pale yellow solid crude product. Recrystallize and purify to obtain a white intermediate one, which is (S)-2,2'-bis(methoxymethoxy)-1,1'-binaphthol ((S)-6). S2. Weigh out white intermediate one and dissolve it in 30 ml of ultra-dry tetrahydrofuran. Cool to -78°C and add n-butyllithium (2.5 eq) dropwise. Restore to room temperature and react for 1 h. When the solution becomes turbid, cool the reaction solution to 0°C and add ultra-dry N,N-dimethylformamide (2.5 eq) dropwise. Restore to room temperature and react for 3 h. Then quench the reaction with saturated ammonium chloride solution under ice-water bath conditions. Extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and rotary evaporate to obtain a yellow solid crude product. Purify by column chromatography and vacuum dry to obtain intermediate two, which is (S)-2,2'-bis(methoxymethoxy)-[1,1'-binaphthyl]-3,3'-dicarboxaldehyde ((S)-7). S3. Weigh intermediate 2 and dissolve it in a mixed solution of 20 ml anhydrous ethanol and 20 ml dichloromethane and stir. Then add HCl (1.5 eq). After the reaction is complete, add 15 ml saturated sodium bicarbonate aqueous solution to quench the reaction. Extract with ethyl acetate, mix the organic phase, dry with anhydrous sodium sulfate, and vacuum distill to remove the solvent to obtain intermediate 3. Intermediate 3 is (S)-2,2'-dihydroxy-[1,1'-binaphthyl]-3,3'-dicarboxaldehyde ((S)-8). S4. Weigh 3.5 equivalents of cesium fluoride and 1.2 equivalents of xylene sulfonate into a two-necked flask, evacuate and purge with nitrogen three times, add 20 ml of anhydrous acetonitrile to fully dissolve the raw material, heat to reflux at 65°C, and after the reaction is complete, restore to room temperature, extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and purify by column chromatography to obtain 8,9,11,12,14,15-hexahydrodinaphthalene[2,1-k:1',2'-m][1,4,7,10]tetraoxocyclotetradecane-6,17-dicarboxaldehyde ((S)-L8), which is the fluorescent probe (S)-L8.

[0018] Example 2 A detection and analysis method for identifying D-aminomannose: P1. Dissolve the fluorescent probe (S)-L8 in dimethyl sulfoxide to obtain a first solution of 1.6 mM; P2. Dissolve aminoglycoside hydrochloride in ultrapure water, and add 1 equivalent of NaHCO3 relative to aminoglycoside hydrochloride to obtain a second solution of 88 mM. P3. Take 50 μL of each of the first and second solutions and add them to another sample vial. P4. Add 300 μL of methanol to the sample vial, mix well and react for 3 h. P5. After the reaction is complete, dilute to 4 mL with methanol to prepare a 0.02 mM third solution. P6. The third solution is placed in a fluorescence spectrometer as the sample to be tested. The sample is detected using a light source with a fixed excitation wavelength of 285 nm. Based on the ratiometric detection effect of the sample fluorescence intensity increasing at 368 nm and quenching at 488 nm, specific and selective fluorescence recognition of D-ManN is achieved.

[0019] The fluorescent probe (S)-L8 was reacted with D-aminomannose (D-ManN), D-glucosamine (D-GluN), D-galactosamine (D-GalN), L / D-serine (Ser), L / D-proline (Pro), L / D-aspartic acid (Asp), L / D-arginine (Arg), L / D-valine (Val), L / D-glucose (Glu), L / D-galactose (Gal), and L / D-mannose (Man), and the results were as follows: Figure 4 As shown, the fluorescent probe (S)-L8 exhibited a specific and selective fluorescence change for D-aminomannose (D-ManN) at an excitation wavelength of 285 nm, enabling ratiometric detection (emission wavelengths of 368 nm and 488 nm), while other analytes showed little or no change.

[0020] Example 3 This example demonstrates the effect of different reaction times on the recognition effect of fluorescent probes. To demonstrate the effect of reaction time on the recognition of D-ManN by the fluorescent probe (S)-L8, 12 experimental groups were set up with reaction times of 0 minutes, 5 minutes, 10 minutes, 30 minutes, 40 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours and 7 hours.

[0021] The results are as follows Figure 5 , Figure 6 As shown: from Figure 5 c shows that during D-ManN recognition, the fluorescence intensity at 368 nm gradually increases with increasing reaction time, while the fluorescence intensity at 488 nm gradually decreases with increasing time. However, after 2 hours of reaction, the increase in I368 / I488 tends to stabilize and is no longer affected by reaction time. from Figure 5 As shown in d, the ratio of I368 to I488 increases after the fluorescent probe (S)-L8 reacts with D-ManN, and the fluorescence emission intensity remains almost stable after 2 hours. However, the ratio of I368 to I488 remains almost unchanged after the fluorescent probe (S)-L8 reacts with D-GluN and D-GalN for up to 7 hours.

[0022] Example 4 The fluorescence enhancement signal of the fluorescent probe (S)-L8 varies when recognizing different concentrations of D-ManN. To demonstrate the effect of amino sugar concentration on the recognition performance of the fluorescent probe (S)-L8, 15 experimental groups were set up relative to probe 1 eq., 5 eq., 10 eq., 15 eq., 20 eq., 25 eq., 30 eq., 35 eq., 40 eq., 45 eq., 50 eq., 55 eq., 60 eq., 65 eq. and 70 eq.

[0023] It was found that even at a concentration as low as 0.02 mM (1 eq.), D-ManN already had a recognition effect. As the D-ManN content increased, the fluorescence intensity at 368 nm increased, while the fluorescence intensity at 488 nm decreased.

[0024] When the D-ManN content reaches 55 eq., the strength no longer changes with increasing D-ManN content.

[0025] from Figure 6 c indicates that during the recognition process of D-ManN, the fluorescence intensity at 368 nm increases with increasing D-ManN content, while the fluorescence intensity at 488 nm decreases. When the D-ManN concentration reaches 55 eq, the intensity no longer changes with increasing D-ManN content.

[0026] from Figure 6d indicates that when the D-ManN content is below 55 eq., I 368 / I 488 The fluorescence enhancement showed a linear increasing trend with D-ManN concentration. When the D-ManN content exceeded 55 eq., the fluorescence enhancement tended to stabilize, indicating that high concentrations of D-ManN did not interfere with the detection results of the fluorescent probe. Furthermore, compared to D-GalN and D-GluN, even at concentrations of 70 eq., they did not cause I... 368 / I 488 The obvious changes.

[0027] The above results highlight the good selectivity of (S)-L8 for D-ManN.

[0028] Example 5 Based on the characteristic that the fluorescent probe (S)-L8 can specifically fluorescently recognize D-ManN from three D-amino sugars without being affected by other chiral amino acids and chiral sugars, it can be applied to the analysis of D-amino sugar composition in different soil matrices.

[0029] The D-amino sugar content in each sample accounted for 5% of the total mass of the soil sample. The soluble components of the three samples were extracted using ultrapure water. After centrifugation and filtration, the supernatant was reacted with the fluorescent probe (S)-L8 for 3 hours for fluorescence signal analysis.

[0030] from Figure 7 It can be seen that in the same soil, with the addition of D-ManN, the fluorescence signal at 488 nm is quenched, while the fluorescence signal at 368 nm is enhanced, and I 368 / I 488 It is significantly stronger than the other two D-amino sugars. Furthermore, the fluorescent probe (S)-L8 exhibits the same selectivity and fluorescence emission intensity in different soils, demonstrating the probe's ability and versatility in specifically recognizing D-ManN in complex matrices.

[0031] from Figure 8 It can be seen that the soil samples contain D-GalN and D-ManN with different compositions. As the content of D-ManN in the soil samples increases, the emission peak of the probe at 488 nm gradually weakens, while the emission peak at 368 nm gradually strengthens. 368 / I 488 It shows an increasing trend.

[0032] from Figure 9 It can be seen that the soil samples contain D-GluN and D-ManN with different compositions. With the addition of D-ManN to the soil samples, the emission peak at 488 nm of the probe's fluorescence signal gradually weakens, while the emission peak at 368 nm gradually strengthens. 368 / I488 It shows an increasing trend.

[0033] The above results demonstrate that the fluorescent probe (S)-L8 has the ability to quantitatively detect D-ManN in complex samples.

[0034] This invention successfully prepared a novel chiral crown ether fluorescent probe (S)-L8 based on a binaphthol skeleton. Furthermore, the synthetic route of the fluorescent probe (S)-L8 of this invention is short and easy to operate.

[0035] The aldehyde group of the fluorescent probe (S)-L8 of the present invention can undergo an imine condensation reaction with the amino group of D-ManN. Due to the differences in the spatial configuration of different amino sugar molecules, the -OH on D-ManN is more likely to form hydrogen bonds with the oxygen atom on the chiral crown ether, which improves the overall rigidity of the fluorescent product and produces stronger fluorescence emission, thereby achieving a specific fluorescent recognition effect.

[0036] The fluorescent probe (S)-L8 of this invention achieves specific fluorescent recognition of 0-55 equivalents of D-ManN, exhibiting high detection stability and immunity to interference from other amino sugars, chiral amino acids, and chiral sugars. Specific, ratiometric detection of D-ManN in complex matrices is achieved by varying the fluorescence intensity at 368 nm and 488 nm under 285 nm excitation. Furthermore, (S)-L8 can be used to analyze the types and composition of amino sugars in different soils.

[0037] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing a fluorescent probe for recognizing D-aminomannose, characterized in that: Includes the following steps, S1. Weigh (S)-binaphthol and sodium hydride, dissolve them separately in ultra-dry tetrahydrofuran, mix the two solutions at 0℃, react for 2 hours, restore to room temperature and continue the reaction, cool to 0℃ after 2 hours and add bromomethyl methyl ether, then restore to room temperature and react again. Then, under ice-water bath conditions, add ultrapure water to quench the reaction, extract with ethyl acetate and combine the organic phases, dry with anhydrous sodium sulfate, and rotary evaporate to obtain a pale yellow solid crude product. Recrystallize and purify to obtain white intermediate one, which is (S)-2,2'-bis(methoxymethoxy)-1,1'-binaphthol ((S)-6); S2. Weigh out white intermediate one, dissolve it in ultra-dry tetrahydrofuran and cool it to -78°C. Then add n-butyllithium to restore the reaction to room temperature. After the solution becomes turbid, cool the solution to 0°C and add ultra-dry N,N-dimethylformamide. After restoring the reaction to room temperature for 3 hours, add saturated ammonium chloride solution to quench the reaction under ice-water bath conditions. Then extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and rotary evaporate to obtain a yellow solid crude product. Purify by column chromatography and dry under vacuum to obtain intermediate two, which is (S)-2,2'-bis(methoxymethoxy)-[1,1'-binaphthyl]-3,3'-dicarboxaldehyde ((S)-7). S3. Weigh intermediate two and dissolve it in a mixed solvent of anhydrous ethanol and dichloromethane. After mixing evenly, add HCl. After the reaction is complete, add pure water and NaHCO3 to quench the reaction. Extract with ethyl acetate, mix the organic phase, dry with anhydrous sodium sulfate, and vacuum distill to remove the solvent to obtain intermediate three. Intermediate three is (S)-2,2'-dihydroxy-[1,1'-binaphthyl]-3,3'-dicarboxaldehyde ((S)-8). S4. Weigh the intermediate tris(t)-fluorinated cesium fluoride and xylene sulfonate into two-necked flasks, evacuate and purge with nitrogen multiple times, add anhydrous acetonitrile to fully dissolve the raw materials, heat to reflux at 65°C until the reaction is complete, then return to room temperature, extract with ethyl acetate, combine the organic phases, dry with anhydrous sodium sulfate, and purify by column chromatography to obtain 8,9,11,12,14,15-hexahydrodinaphthalene[2,1-k:1',2'-m][1,4,7,10]tetraoxanetetradecane-6,17-dicarboxaldehyde ((S)-L8), which is the fluorescent probe (S)-L8.

2. The method for preparing a fluorescent probe for recognizing D-aminomannose according to claim 1, characterized in that: In step S1, the equivalent ratio of (S)-binaphthol, sodium hydride, and bromomethyl methyl ether is 1:6:

4.

3. The method for preparing a fluorescent probe for recognizing D-aminomannose according to claim 2, characterized in that: In step S2, the ratio of n-butyllithium to N,N-dimethylformamide is 1:1, and the equivalent of n-butyllithium is 2.5; the eluent used in silica gel column purification consists of petroleum ether and ethyl acetate in a volume ratio of 10:

1.

4. The method for preparing a fluorescent probe for recognizing D-aminomannose according to claim 3, characterized in that: In step S3, the volume ratio of anhydrous ethanol to dichloromethane is 1:1, and the amount of HCl is 1.5 equivalents.

5. The method for preparing a fluorescent probe for recognizing D-aminomannose according to claim 4, characterized in that: In step S4, cesium fluoride is 5 equivalents relative to 1 equivalent of (S)-L8; xylene sulfonate is 1.2 equivalents; and the eluent used in silica gel column purification consists of petroleum ether and ethyl acetate in a volume ratio of 10:

1.

6. A method for detecting and analyzing D-aminomannose, characterized in that: Includes the following steps, P1. Dissolve the fluorescent probe (S)-L8 in dimethyl sulfoxide to obtain the first solution; P2. Dissolve aminoglycoside hydrochloride in ultrapure water, and add NaHCO3 relative to aminoglycoside hydrochloride to obtain a second solution of 88 mM. P3. Take a portion of the solution from the first solution and the second solution, and add them to another sample bottle; P4. Add methanol to the sample vial, mix well and react. P5. After the reaction is complete, dilute the solution to volume with methanol to prepare the third solution. P6. The third solution is placed in a fluorescence spectrometer as the sample to be tested. The sample is detected using a light source with a fixed excitation wavelength of 285 nm. Based on the ratiometric detection effect of the sample fluorescence intensity increasing at 368 nm and quenching at 488 nm, specific and selective fluorescence recognition of D-ManN is achieved.

7. The detection and analysis method for identifying D-aminomannose according to claim 6, characterized in that: During the reaction, ratiometric fluorescence analysis of D-ManN was achieved by detecting the changes in fluorescence intensity at 368 nm and 488 nm.

8. The detection and analysis method for identifying D-aminomannose according to claim 7, characterized in that: When using the fluorescent probe (S)-8, fluorescence detection was performed at 368 nm and 488 nm, with an excitation wavelength of 285 nm.

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