SO2 derivative and polarity dual-response molecular sensor based on FRET mechanism as well as preparation method and application of SO2 derivative and polarity dual-response molecular sensor

Abstract

The invention relates to an FRET (fluorescence resonance energy transfer) mechanism-based SO2 derivative and polarity dual-response molecular sensor and a preparation method and application thereof, the chemical structural formula is as shown in the specification, the molecular sensor can specifically respond to the change of polarity and SO2 derivatives, the fluorescence intensity at 449nm is gradually enhanced along with the increase of the concentration of the SO2 derivatives in a detection system, and the fluorescence intensity at 449nm is gradually increased. The fluorescence intensity at 633nm is gradually weakened, and the function Ln (IR49 / I633) of the fluorescence intensity ratio and the concentration of the SO2 derivative have a linear relationship within a certain range. Along with the reduction of polarity in a detection system, the fluorescence emission peak of the probe at 633nm is gradually increased, and the fluorescence intensity (I633) is in a linear relationship with the change of polarity in a solvent system within a certain range. Besides, the probe can detect the ratio of an actual water sample to the SO2 derivative in food, is expected to play a role in analysis and detection of environment, food and medicines, and has a wide application prospect. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to an SO derivative and a polarity dual-responsive molecular sensor based on the FRET mechanism, and a preparation method and application thereof, belonging to the field of new material detection. 2 Background Art

[0002] Sulfur dioxide (SO 2 ) is a common harmful gas, which usually exists in water sources, foods, and organic organisms in the form of sulfite (SO 3 2- ) or bisulfite (HSO 3 - ). In addition, SO 3 2- / HSO 3 - has the functions of bleaching and sterilization and is widely used in the food processing process. Ingesting excessive SO 3 2- / HSO 3 - can cause diseases such as cardiovascular diseases, metabolic disorders, and even cancer. Real-time and accurate monitoring of the content level of SO 3 2- / HSO 3 - in water sources and foods helps to reduce the intake of SO 3 2- / HSO 3 - and is of great significance for improving the environment and promoting human health. In addition, as an important evaluation index of the environment in organic organisms, the irregular change of polarity is usually related to metabolic disorders and even diseases in organisms. In-situ and real-time detection of the polarity change in the environment of organic organisms is of great significance for the prevention and diagnosis of related diseases.

[0003] A fluorescence sensor based on the fluorescence energy resonance transfer (FRET) mechanism usually consists of three parts, namely an energy donor, a linker, and an energy acceptor. After the energy donor absorbs the excitation energy, it transfers the energy to the energy acceptor through the FRET process. At this time, the fluorescence signal of the energy donor decreases or even disappears, while the fluorescence signal of the energy acceptor increases significantly. As the concentration of SO 3 2- / HSO 3 - in the system increases, the FRET process is gradually blocked, showing a gradually increasing donor fluorescence and a gradually decreasing acceptor fluorescence. Therefore, the fluorescence intensity ratio of the donor and the acceptor is related to HSO 3 - / SO 3 ​2- The concentration shows a functional relationship within a certain range. However, existing FRET-based molecular sensors still have drawbacks such as small Stokes shift, small emission peak spacing, and short emission wavelength. In addition, most of the currently reported FRET-based HSO 3 - / SO 3 2- fluorescent sensors are single-response types and cannot achieve simultaneous response to HSO 3 - / SO 3 2- and polarity.

[0004] In order to prepare an FRET-based sensor with excellent performance, a novel FRET molecular sensor is designed and prepared using excellent fluorescent energy donors and fluorescent energy acceptors. After retrieval and investigation, there are few reports on HSO 3 - / SO 3 2- and polarity dual-response molecular sensors based on the FRET mechanism and their applications. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides an SO 2 derivative and polarity dual-response molecular sensor based on the FRET mechanism, as well as its preparation method and application.

[0006] In the first aspect of the present invention, there is provided an SO 2 derivative and polarity dual-response molecular sensor based on the FRET mechanism.

[0007] The SO 2 derivative and polarity dual-response molecular sensor based on the FRET mechanism has the following chemical structural formula as shown in Formula I:

[0008]

[0009] Preferably according to the present invention, the dual-response molecular sensor N,N-dimethyl-4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzamide is used as the energy donor, (E)-2-(3-cyano-4-(4-(diethylamino)styryl)-5,5-dimethylfuran-2(5H)-ylidene)malononitrile is used as the energy acceptor, and piperazine is used as the linker.

[0010] In the second aspect of the present invention, there is provided a preparation method for the above-mentioned SO 2 derivative and polarity dual-response molecular sensor based on the FRET mechanism.

[0011] The above-mentioned SO 2Preparation method of derivatives and polar dual-responsive molecular sensors, comprising the following steps:

[0012] 4-(1-Methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid and (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)styryl)furan-2(5H)-ylidene)malononitrile are condensed in an organic solvent to obtain SO based on the FRET mechanism 2 Derivatives and polar dual-responsive molecular sensors.

[0013] Preferably according to the present invention, the molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)styryl)furan-2(5H)-ylidene)malononitrile is (1-2):(1-2).

[0014] Most preferably, the molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)styryl)furan-2(5H)-ylidene)malononitrile is 1:1.

[0015] Preferably according to the present invention, the condensation is carried out in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride EDC and 4-dimethylaminopyridine DMAP.

[0016] More preferably, the molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to EDC is (1-2):(1-2).

[0017] Preferably according to the present invention, the molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to DMAP is (4-8):1.

[0018] Preferably according to the present invention, the organic solvent is dichloromethane.

[0019] Preferably according to the present invention, the molar amount of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to the volume of the organic solvent is 1:(20-40), unit, mmol / mL.

[0020] In the second aspect of the present invention, the application of the above-mentioned SO 2 Derivatives and polar dual-responsive molecular sensors based on the FRET mechanism is provided.

[0021] The above-mentioned SO based on the FRET mechanism 2Applications of derivatives and polar dual-responsive molecular sensors for fluorescence detection or ultraviolet detection of the concentration or residue amount of sulfite or bisulfite in water sources and foods, or for detecting solutions with polarity differences.

[0022] Specifically, the fluorescence detection method is as follows:

[0023] (1) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing the dual-responsive molecular sensor, add known concentrations of HSO 3 - / SO 3 2- to it, measure the relationship between the fluorescence intensities of the sensor at 449 and 633 nm and the concentration, use the concentration of HSO 3 - / SO 3 2- as the abscissa, and the fluorescence intensity ratio (I 449 / I 633 ) as the ordinate to obtain the working curve between the two;

[0024] (2) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing the dual-responsive molecular sensor, add different volumes of the sample solution to be measured, measure the fluorescence intensities at 449 and 633 nm, and according to the working curve between the concentration of HSO 3 - / SO 3 2- and the fluorescence intensity ratio (I 449 / I 633 ), obtain the concentration of HSO 3 - / SO 3 2- in the sample to be measured.

[0025] Specifically, the ultraviolet detection method is as follows:

[0026] 1) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing the dual-responsive molecular sensor, add known concentrations of HSO 3 - / SO 3 2- , measure the relationship between the ultraviolet absorption intensities of the sensor at 328 and 573 nm and the concentration, use the concentration of HSO 3 - / SO 3 2- as the abscissa, and the ultraviolet absorption intensity ratio (I 328 / I 573) Plot a graph with the ordinate to obtain the working curve between the two;

[0027] 2) Prepare a solution containing the dual-responsive molecular sensor, ethanol, and PBS buffer (V / V, 5 / 5, pH = 7.4). Add different equal volumes of the sample solution to be measured, and measure the ultraviolet absorption intensity at 328 and 573 nm. According to the ratio of the concentration of HSO 3 - / SO 3 2- and the ultraviolet absorption intensity ratio (I 328 / I 573 ), obtain the working curve, and get the concentration of HSO 3 - / SO 3 2- in the sample solution to be measured.

[0028] Preferably according to the present invention, the solution with polarity difference is a mixed solution of 1,4-dioxane and PBS in different ratios.

[0029] In the absence of HSO 3 - / SO 3 2- , after the energy donor absorbs energy, it transfers the energy to the energy acceptor through the FRET process, and at this time, it shows the fluorescence of the energy acceptor; in the presence of HSO 3 - / SO 3 2- , the styrene double bond in the energy acceptor part reacts with HSO 3 - / SO 3 2- to form an addition product as shown in Formula II. The structure of the energy acceptor is destroyed, the FRET process is blocked, and the fluorescence of the energy donor is emitted. According to the different concentrations of HSO 3 - / SO 3 2- , the fluorescence intensities of the donor and the acceptor change, so as to realize the ratio detection of HSO 3 - / SO 3 2- . In addition, the sensor itself emits the fluorescence of the energy acceptor. Under the condition of decreasing polarity, the intramolecular twisted charge transfer process (TICT) of the energy acceptor molecule weakens, and the fluorescence intensity of the energy acceptor increases, achieving the recognition response to polarity. Based on this, the above sensor realizes the detection of HSO 3 - / SO 3 2-And dual detection effects of polarity.

[0030]

[0031] Technical features and advantages of the present invention:

[0032] 1. The dual-responsive molecular sensor of the present invention based on the FRET mechanism can not only detect the concentration change of HSO 3 - / SO 3 2- , but also can be used to detect the polarity change in the system; importantly, it can be used for the determination of the concentration of HSO 3 - / SO 3 2- in water samples and foods. Therefore, it is expected to play a role in environmental and food quality monitoring and has broad application prospects.

[0033] 2. The dual-responsive molecular sensor of the present invention based on the FRET mechanism can detect SO 3 2- / HSO 3 - and polarity in real time, in situ, with low detection limit, high selectivity and sensitivity, and has the advantage of "killing two birds with one stone", and can realize the simultaneous recognition response to SO 3 2- / HSO 3 - and polarity.

[0034] 3. The dual-responsive molecular sensor of the present invention has excellent selectivity, good anti-interference ability and fast response characteristics, and can realize rapid detection.

[0035] 4. The lowest detection limit of the dual-responsive molecular sensor of the present invention is 0.44 μM, and the sensitivity is higher. It can not only meet the detection requirements of sulfite / bisulfite in water sources, but also can realize the rapid detection of sulfite / bisulfite in foods or drugs.

[0036] 5. The dual-responsive molecular sensor of the present invention has a wide detection range. In water samples (tap water, Yellow River, Baotu Spring, Daming Lake, Taibai Lake and Beijing-Hangzhou Grand Canal) and foods (granulated sugar, wine, mushrooms and dried bean curd), the sensor shows good spike recovery rates. Description of the Drawings

[0037] Figure 1 1H NMR spectrum of the SO 2 derivative and dual-responsive molecular sensor based on the FRET mechanism prepared in Example 1.

[0038] Figure 2Fluorescence (left figure) and ultraviolet absorption spectrogram (right figure) of the dual-responsive molecular sensor of the present invention in response to analytes such as anions and biothiols.

[0039] Figure 3 For the dual-responsive molecular sensor of the present invention in the presence of anions, biothiols, etc. and HSO 3 - / SO 3 2- Response fluorescence (left figure) and ultraviolet absorption spectrum (right figure).

[0040] Figure 4 For the dual-responsive molecular sensor of the present invention to HSO 3 - / SO 3 2- Change of the fluorescence intensity ratio in response to time measurement.

[0041] Figure 5 For the fluorescence spectral changes (a) of the dual-responsive molecular sensor of the present invention at 443 nm and 633 nm, and the linear relationship diagram (b) between its ratio function and the concentration of HSO 3 - / SO 3 2- Concentration.

[0042] Figure 6 For the ultraviolet-visible absorption spectral changes (c) of the dual-responsive molecular sensor of the present invention at 328 nm and 573 nm, and the linear relationship diagram (d) between its ratio function and the concentration of HSO 3 - / SO 3 2- Concentration.

[0043] Figure 7 For the fluorescence spectrum (a) of the dual-responsive molecular sensor of the present invention at 633 nm, and the linear relationship diagram (b) between the function of the fluorescence intensity and the polarity of the detection system. Detailed implementation method

[0044] Example 1

[0045] Preparation method of an SO 2 derivative and a polarity dual-responsive molecular sensor based on the FRET mechanism, the steps are as follows:

[0046] 1 mmol of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid, 1 mmol of (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)styryl)furan-2(5H)-ylidene)malononitrile, 1 mmol of EDC and 0.2 mmol of DMAP were dissolved in 30 mL of dry dichloromethane and stirred at room temperature for 24 h in a nitrogen atmosphere to obtain a mixture. The product was separated by column chromatography and purified to obtain the SO 2 derivative and polar dual-responsive molecular sensor, named TLA, as a solid with a yield of 52%.

[0047] Structure confirmation spectral data:

[0048] 1 H NMR (500 MHz, DMSO-d 6 ): 1.770 (s, 6H), 3.608 - 3.828 (m, 8H), 4.344 (s, 3H), 6.974 (d, J = 16.0 Hz, 1H), 7.042 (d, J = 8.5 Hz, 2H), 7.647 - 7.833 (m, 8H), 7.648 (d, J = 16.0 Hz, 1H), 7.990 (d, J = 8.0 Hz, 2H).

[0049] 13 C NMR (125 MHz, DMSO-d 6 ): 25.978, 36.630, 52.462, 55.374, 94.572, 99.047, 110.507, 112.150, 114.451, 121.868, 125.733, 128.054, 136.828, 137.176, 159.158, 151.779, 153.931, 169.170, 176.096, 177.798.

[0050]

[0051] Example 2

[0052] Into a 10 mL volumetric flask containing 5 μM of the dual-responsive molecular sensor prepared in Example 1, NO 2 - , C 2 O 4 2- , CH 3 COO - , NO 3 - , S 2 O 32- , S 2- , SO 4 2- , HCO 3 - , CO 3 2- , F - , Cl - , Br - , I - , GSH, Cys, Gly, Hcy, H 2 O 2 , NH 4 + , HSO 3 - / SO 3 2- , to make the concentration reach 50 μM. After acting for 30 min, fluorescence emission and ultraviolet-visible absorption spectroscopy tests were respectively carried out, and the results are shown in Figure 2 .

[0053] The results show that the dual-responsive molecular sensor of the present invention has good selectivity for HSO 3 - / SO 3 2- .

[0054] Example 3

[0055] To a 10 mL volumetric flask containing 5 μM of the dual-responsive molecular sensor prepared in Example 1, NO 2 - , C 2 O 4 2- , CH 3 COO - , NO 3 - , S 2 O 3 2- , S 2- , SO 4 2- , HCO 3 - , CO 3 2- , F - , Cl - , Br - , I - , GSH, Cys, Gly, Hcy, H 2 O 2 , NH 4 +; Adjust the concentration to 50 μM, and then add HSO 3 - / SO 3 2- After reacting for 30 min, fluorescence emission and ultraviolet-visible absorption spectroscopy tests were carried out. The results are as Figure 3 .

[0056] The results showed that in the presence of the above interfering ions (NO 2 - , C 2 O 4 2- , CH 3 COO - , NO 3 - , S 2 O 3 2- , S 2- , SO 4 2- , HCO 3 - , CO 3 2- , F - , Cl - , Br - , I - , GSH, Cys, Gly, Hcy, H 2 O 2 , NH 4 + ), the dual-responsive molecular sensor of the present invention can still react well with HSO 3 - / SO 3 2- , indicating that the above sensor has good anti-interference ability in detecting HSO 3 - / SO 3 2- .

[0057] Example 4

[0058] To a 10 mL volumetric flask containing 5 μM of the dual-responsive molecular sensor prepared in Example 1, add HSO 3 - / SO 3 2- , adjust the concentration to 50 μM, and measure the change relationship of the fluorescence intensity ratio (I 449 / I 633 ) at 449 and 633 nm with time. The results are shown in Figure 4 .

[0059] The results show that the dual-responsive molecular sensor of the present invention detects HSO 3 - / SO 3 2- and has the advantage of rapid response.

[0060] Example 5

[0061] In a 10 ml volumetric flask containing 5 μM of the dual-responsive molecular sensor prepared in Example 1, different concentrations of HSO 3 - / SO 3 2- were added. After reacting for 30 min, fluorescence tests were carried out. The test results are shown in Figure 5 .

[0062] The results show that with the increase in the concentration of HSO 3 - / SO 3 2- in the dual-responsive molecular sensor of the present invention, the fluorescence intensity at 449 nm gradually increases, and the fluorescence intensity at 633 nm gradually decreases. The function of the fluorescence intensity ratio (Ln(I 449 / I 633 )) has a linear relationship with the concentration of HSO 3 - / SO 3 2- within a certain range. Therefore, the sensor of the present invention can accurately and quantitatively detect HSO 3 - / SO 3 2- , as shown in Figure 5 .

[0063] Example 6

[0064] In a 10 ml volumetric flask containing 5 μM of the dual-responsive molecular sensor prepared in Example 1, different concentrations of HSO 3 - / SO 3 2- were added. After reacting for 30 min, ultraviolet-visible spectroscopy tests were carried out. The results are shown in Figure 6 .

[0065] The results show that with the increase in the concentration of HSO 3 - / SO 3 2- in the dual-responsive molecular sensor of the present invention, the ultraviolet absorption intensity at 328 nm gradually increases, and the ultraviolet absorption intensity at 573 nm gradually decreases. The function of the absorbance ratio (Ln(A 328 / A 573)) and HSO 3 - / SO 3 2- has a linear relationship within a certain range of concentration. Therefore, the sensor of the present invention can also quantitatively detect HSO 3 - / SO 3 2- by ultraviolet-visible spectrophotometry. See Figure 6 .

[0066] Example 7

[0067] In a 10 ml volumetric flask containing 5 μM of the dual-response molecular sensor prepared in Example 1, different ratios of 1,4-dioxane and PBS (V / V) mixed solution were added to make up the volume, and the fluorescence spectrum was measured. The results are as Figure 7 .

[0068] The results show that as the polarity in the system decreases, the fluorescence intensity of the sensor at 633 nm gradually increases, and the change of the fluorescence intensity function with respect to the polarity is linearly related within a certain range. Therefore, the sensor can quantitatively analyze and monitor the polarity change in the system.

[0069] Example 8

[0070] In a 10 ml volumetric flask containing 5 μM of the dual-response molecular sensor prepared in Example 1, a certain amount of ethanol and PBS mixed solution containing water samples or food samples was added to make up the volume, and the fluorescence spectrum was measured; or different concentrations of HSO 3 - / SO 3 2- was added to the above samples to measure the spike recovery rate.

[0071] The results show that the probe detection can effectively detect the concentration of HSO 3 - / SO 3 2- in food; and when the added HSO 3 - / SO 3 2- in the actual sample, it has a good spike recovery rate. The results are shown in Table 1.

[0072] Table 1 Detection results and spike recovery rates of the sensor in actual water samples and foods

[0073]

[0074]

[0075]

[0076] In the water samples (tap water, Yellow River, Baotu Spring, Daming Lake, Taibai Lake and Beijing-Hangzhou Grand Canal) and foods (white granulated sugar, wine, mushrooms and dried bean curd sticks) added with the sensor of the present invention, the sensor showed good spike recovery rates and quantitatively analyzed and detected the content of HSO 3 - / SO 3 2- in the foods.

Claims

1. SO2 derivatives and polar dual-response molecular sensors based on FRET mechanism, the chemical structure of which is shown in Formula I below: Preferably according to the present invention, the dual-response molecular sensor N,N-dimethyl-4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzamide is an energy donor, (E)-2-(3-cyano-4-(4-(diethylamino)phenylvinyl)-5,5-dimethylfuran-2(5H)-ylidene)malononitrile is an energy acceptor, and piperazine is a connector.

2. The method for preparing the SO2 derivative and polar dual-response molecular sensor based on the FRET mechanism according to claim 1 comprises the following steps: 4-(1-Methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid and (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)phenylvinyl)furan-2(5H)ylidene)malononitrile were condensed in an organic solvent to obtain a SO2 derivative and a polar dual-responsive molecular sensor based on the FRET mechanism.

3. The preparation method according to claim 2, characterized in that: The molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)phenylvinyl)furan-2(5H)ylidene)malononitrile is (1-2):(1-2), preferably, the molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to (E)-2-(3-cyano-5,5-dimethyl-4-(4-(piperazin-1-yl)phenylvinyl)furan-2(5H)ylidene)malononitrile is 1:

1.

4. The preparation method according to claim 2, characterized in that: The condensation is carried out in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride EDC and 4-dimethylaminopyridine DMAP.

5. The preparation method according to claim 4, characterized in that: The molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to EDC (1-2): (1-2), the molar ratio of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to DMAP (4-8):

1.

6. The preparation method according to claim 2, characterized in that: The organic solvent is dichloromethane, and the volume ratio of the molar amount of 4-(1-methyl-1H-phenanthro[9,10-d]imidazol-2-yl)benzoic acid to the organic solvent is 1:(20-40), unit, mmol / mL.

7. The use of the SO2 derivative and polar dual-response molecular sensor based on the FRET mechanism as described in claim 1 is used for fluorescence detection or ultraviolet detection of the concentration or residual amount of sulfite or bisulfite in water sources and food, or for detecting solutions with polarity differences.

8. The use according to claim 7, characterized in that: The fluorescence detection method is as follows: (1) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing a dual-response molecular sensor, and add a known concentration of HSO3 to the solution. - / SO3 2- , the fluorescence intensity of the sensor at 449 and 633 nm was measured as a function of concentration, using HSO3 - / SO3 2- The concentration is the horizontal axis, and the fluorescence intensity ratio (I 449 / I 633 ) as the ordinate, and obtain the working curve between the two; (2) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing a dual-response molecular sensor, add different volumes of the sample solution to the solution, and measure the fluorescence intensity at 449 and 633 nm. - / SO3 2- The ratio of concentration to fluorescence intensity (I 449 / I 633 ) to obtain the HSO3 of the sample to be tested. - / SO3 2- concentration.

9. The use according to claim 7, characterized in that: The UV detection method is as follows: 1) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing a dual-response molecular sensor, and add HSO3 of known concentration to the solution. - / SO3 2- , the relationship between the UV absorption intensity of the sensor at 328 and 573 nm and the concentration was measured, with HSO3 - / SO3 2- The concentration is the horizontal axis, and the ultraviolet absorption intensity ratio (I 328 / I 573 ) is used as the ordinate to draw a graph and obtain the working curve between the two; 2) Prepare a solution of ethanol and PBS buffer (V / V, 5 / 5, pH = 7.4) containing a dual-response molecular sensor, add different volumes of the sample solution to the solution, measure the ultraviolet absorption intensity at 328 and 573 nm, and calculate the absorption intensity of the sample solution according to the concentration of HSO3 - / SO3 2- The ratio of concentration to UV absorption intensity (I 328 / I 573 ) to obtain the sample solution HSO3 - / SO3 2- concentration.

10. The use according to claim 7, characterized in that: The solutions with different polarities are mixtures of 1,4-dioxane and PBS in different proportions.

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