A dual-emission fluorescent probe for detecting tricresyl phosphate and preparation method and application thereof

Abstract

The application discloses a dual-emission fluorescent probe for detecting cresyl phosphate as well as a preparation method and application thereof, and solves the technical problems of high cost and low timeliness in the prior art cresyl phosphate detection. The dual-emission fluorescent probe for detecting cresyl phosphate has characteristic peaks of Al2p, C1s, N1s and O1s in an XPS full spectrum diagram; has characteristic peaks of O-H / N-H, -COO, Al-O and C=O in an FT-IR spectrum diagram; and has dual-emission wavelengths in a fluorescence spectrum. The preparation method of the dual-emission fluorescent probe for detecting cresyl phosphate comprises the following steps: obtaining an aqueous solution containing an aluminum salt and a porphyrin; loading the aqueous solution into a reaction kettle to perform a hydrothermal reaction; and collecting and washing the precipitate after the hydrothermal reaction is completed, so that the dual-emission fluorescent probe for detecting cresyl phosphate is obtained. The dual-emission fluorescent probe has a wide linear range, a short response time, strong anti-interference ability and specific recognition ability, is successfully applied to the analysis of cresyl phosphate in lake water and tap water, and has strong practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tricresyl phosphate detection, and in particular to a dual-emission fluorescent probe for detecting tricresyl phosphate, and a preparation method and application thereof. BACKGROUND

[0002] Tricresyl phosphate (TCP) is often added in hydraulic oil, engine oil and lubricating oil. Ecotoxicological assessment of TCP has neurotoxicity, reproductive toxicity, hepatotoxicity and endocrine disruption. Due to high hydrophobicity and high bioaccumulation factor, TCP has moderate risk to organisms. Therefore, TCP is restricted or banned in many countries and regions, including the European Union, the United States, Canada, Japan and Australia.

[0003] However, TCP is still produced and used in some regions, for example, the annual production of TCP in China reached 9675 tons in 2020. Due to migration and exposure in the environment, TCP is detected in water sources such as rivers, lakes and drinking water, with concentrations as low as ng / L and as high as μg / L. In addition to commonly used chromatography, mass spectrometry and chromatography-tandem mass spectrometry, TCP can also be indirectly quantitatively analyzed by electrochemical hydrolysis to generate cresol, but the above methods have the problems of high cost and low timeliness. SUMMARY

[0004] The main purpose of the present application is to provide a dual-emission fluorescent probe for detecting tricresyl phosphate and a preparation method and application thereof, so as to solve the technical problems of high cost and low timeliness in the prior art for detecting tricresyl phosphate.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, a dual-emission fluorescent probe for detecting tricresyl phosphate is provided, and the technical solution is as follows:

[0006] The dual-emission fluorescent probe for detecting tricresyl phosphate is characterized in that: the XPS full spectrum has characteristic peaks of Al2p, C1s, N1s and O1s; the FT-IR spectrum has characteristic peaks of O-H / N-H, -COO, Al-O and C=O; and the fluorescence spectrum has dual-emission wavelengths.

[0007] As a further improvement of the first aspect of the present application: obtained by hydrothermal reaction of an aluminum salt and a porphyrin.

[0008] In order to achieve the above-mentioned purpose, according to the second aspect of the present application, a preparation method of the dual-emission fluorescent probe for detecting tricresyl phosphate is provided, and the technical solution is as follows:

[0009] The preparation method of the dual-emission fluorescent probe for detecting cresyl phosphate comprises the following steps: obtaining an aqueous solution comprising an aluminum salt and a porphyrin; loading the aqueous solution into a reaction kettle for hydrothermal reaction; and collecting and washing the precipitate after the hydrothermal reaction to obtain the dual-emission fluorescent probe for detecting cresyl phosphate.

[0010] As a further improvement of the second aspect of the present application, the aqueous solution is prepared according to the following ratio: 0.4-0.8 mmol Al(NO3)3.9H2O and 0.1-0.3 mmol tetra(4-carboxyphenyl)porphyrin per 30 mL of the aqueous solution.

[0011] As a further improvement of the second aspect of the present application, the hydrothermal reaction temperature is 160-200 DEG C, and the reaction time is 12-20 hours.

[0012] As a further improvement of the second aspect of the present application, the precipitate is washed with DMF and methanol.

[0013] To achieve the above-mentioned purpose, according to the third aspect of the present application, a method for detecting cresyl phosphate is provided, and the technical scheme is as follows:

[0014] The method for detecting cresyl phosphate comprises the following steps: obtaining a first fluorescence intensity, which is the fluorescence intensity of a first solution comprising a dual-emission fluorescent probe; obtaining a second fluorescence intensity, which is the fluorescence intensity of a second solution comprising a to-be-detected liquid and the dual-emission fluorescent probe; substituting the ratio of the second fluorescence intensity to the first fluorescence intensity into a linear equation of the ratio and the cresyl phosphate concentration to obtain the cresyl phosphate concentration in the second solution, thereby obtaining the cresyl phosphate concentration in the to-be-detected liquid; and the dual-emission fluorescent probe is the dual-emission fluorescent probe for detecting cresyl phosphate according to the first aspect or the dual-emission fluorescent probe for detecting cresyl phosphate prepared by the preparation method according to the second aspect.

[0015] As a further improvement of the third aspect of the present application, the excitation wavelength is 415 nm, the concentration of the dual-emission fluorescent probe in the first solution and the second solution is 28-32 mg / L, and the detection limit of cresyl phosphate is 0.082 μmol / L.

[0016] As a further improvement of the third aspect of the present application, when the emission wavelength is 655 nm, the linear equation when the cresyl phosphate concentration is 0.5-5 μmol / L is y=0.102x+0.987, and the linear equation when the cresyl phosphate concentration is 5-30 μmol / L is y=1.09x-3.95, y is the ratio of the second fluorescence intensity to the first fluorescence intensity, and x is the cresyl phosphate concentration in the second solution.

[0017] As a further improvement of the third aspect of the present application: when the emission wavelength is 715 nm, the linear equation of the cresyl phosphate concentration of 0.5-5 μmol / L is y=0.105x+0.993, and the linear equation of the cresyl phosphate concentration of 5-30 μmol / L is y=0.490x-0.920, y is the ratio of the second fluorescence intensity to the first fluorescence intensity, and x is the cresyl phosphate concentration in the second solution.

[0018] When the double-emission fluorescent probe of the present application is used to detect cresyl phosphate, the π-π stacking effect between the benzene ring of the cresyl phosphate and the aromatic ring on the double-emission fluorescent probe makes the cresyl phosphate adsorbed on the surface of the double-emission fluorescent probe, and further makes the double peaks of the double-emission fluorescent probe significantly blue-shifted, at the same time, the strong affinity between the Al-O cluster in the double-emission fluorescent probe and the phosphate group leads to the ligand exchange between the cresyl phosphate and the carboxyl group in the double-emission fluorescent probe, and the formed Al-O-P limits the organic ligand-metal charge transfer (LMCT) effect in the double-emission fluorescent probe, thereby significantly enhancing the fluorescence of the double-emission fluorescent probe, and thus the present application successfully forms a cresyl phosphate sensing method based on the double-emission fluorescence enhancement response.

[0019] Compared with the single-emission fluorescent probe, the double-emission fluorescent probe of the present application has outstanding selectivity, a wide linear range, small background interference, and can significantly improve the accuracy of the detection results.

[0020] It has been verified that under the optimal detection conditions, the double-emission fluorescent probe of the present application has a detection limit of cresyl phosphate as low as 0.082 μmol / L, a wide linear range, a short response time, strong anti-interference ability and specific recognition ability, and is successfully applied to the analysis of cresyl phosphate in lake water and tap water, and has strong practicability.

[0021] The present application will be further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the present application will be partially given in the following description, partially will become apparent from the following description, or will be understood by those skilled in the art through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which form a part of the present application, are used to assist in the understanding of the present application, and the content provided in the accompanying drawings and the description thereof related to the present application can be used to explain the present application, but do not constitute an improper limitation on the present application. In the drawings:

[0023] Figure 1 XRD spectrum of the double-emission fluorescent probe of the present application for detecting cresyl phosphate.

[0024] Figure 2The FT-IR spectrum of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application.

[0025] Figure 3 The XPS full spectrum of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application.

[0026] Figure 4 The fluorescence detection result graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application under different use concentrations.

[0027] Figure 5 The fluorescence detection result graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application under different pH values.

[0028] Figure 6 The fluorescence detection result graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application under different reaction times.

[0029] Figure 7 The fluorescence detection result graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application under different reaction temperatures.

[0030] Figure 8 The fluorescence emission spectrum graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application under different TCP concentrations.

[0031] Figure 9 The linear fitting graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application at 655 nm when detecting TCP.

[0032] Figure 10 The linear fitting graph of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application at 715 nm when detecting TCP.

[0033] Figure 11 The test result graph of the specific recognition performance of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application.

[0034] Figure 12 The test result graph of the anti-interference performance of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application.

[0035] Figure 13 The XPS fine spectrum of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application before and after use at C1s.

[0036] Figure 14 The XPS fine spectrum of the dual-emission fluorescent probe for detecting cresyl phosphate according to the application before and after use at N1s.

[0037] Figure 15XPS fine spectrum of P2p before and after using the dual-emission fluorescent probe for detecting cresyl phosphate according to the present application.

[0038] Figure 16 XPS fine spectrum of Al2p before and after using the dual-emission fluorescent probe for detecting cresyl phosphate according to the present application.

[0039] Figure 17 XPS fine spectrum of O1s before and after using the dual-emission fluorescent probe for detecting cresyl phosphate according to the present application.

[0040] Figure 18 SEM photo of the dual-emission fluorescent probe for detecting cresyl phosphate according to the present application before use.

[0041] Figure 19 SEM photo of the dual-emission fluorescent probe for detecting cresyl phosphate according to the present application after use. DETAILED DESCRIPTION

[0042] The present application will be further described below in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present application based on these descriptions. Before the present application is described in conjunction with the accompanying drawings, it is to be noted that:

[0043] The technical solutions and technical features provided in each part of the present application, including the following descriptions, can be combined with each other without conflict.

[0044] In addition, the embodiments of the present application involved in the following descriptions are generally only a part of the embodiments of the present application, not all the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative labor should belong to the scope of protection of the present application.

[0045] Regarding the terms and units in the present application. The terms "comprise", "have" and any variations thereof in the specification and claims of the present application and related parts are intended to cover non-exclusive inclusion.

[0046] The embodiment of the preparation method of the dual-emission fluorescent probe for detecting cresyl phosphate provided by the application is as follows: first, an aqueous solution containing Al(NO3)3·9H2O and tetra(4-carboxyphenyl)porphyrin (denoted as H2TCPP below) is obtained, and the aqueous solution is configured according to a ratio of 0.4-0.8 mmol Al(NO3)3·9H2O and 0.1-0.3 mmol tetra(4-carboxyphenyl)porphyrin per 30 mL of the aqueous solution. Then the aqueous solution is loaded into a reaction kettle for hydrothermal reaction, and the hydrothermal reaction temperature is 160-200℃, and the reaction time is 12-20 hours. After the hydrothermal reaction is completed, the precipitate is collected and washed with DMF and methanol, and the dual-emission fluorescent probe for detecting cresyl phosphate is obtained. Thus, the H2TCPP containing four pyrrole N atoms in the center of the molecular structure is used as an organic ligand, the metal aluminum ion is introduced on the H2TCPP, the charge transfer between the organic ligand and the metal ion is formed, and the fluorescence function is further significantly enhanced compared with the H2TCPP.

[0047] The content of Al(NO3)3·9H2O in the aqueous solution can be but is not limited to any one of 0.4 mmol, 0.5 mmol, 0.6 mmol, 0.7 mmol, and 0.8 mmol, and the content of H2TCPP can be but is not limited to any one of 0.1 mmol, 0.15 mmol, 0.2 mmol, 0.25 mmol, and 0.3 mmol.

[0048] The hydrothermal temperature can be but is not limited to any one of 160℃, 170℃, 180℃, 190℃, and 200℃, and the hydrothermal time can be but is not limited to any one of 12 hours, 14 hours, 16 hours, 18 hours, and 20 hours.

[0049] The embodiment of the method for detecting cresyl phosphate provided by the application is as follows: a first fluorescence intensity is obtained, which is the fluorescence intensity of a first solution containing the above-mentioned dual-emission fluorescent probe; a second fluorescence intensity is obtained, which is the fluorescence intensity of a second solution containing a to-be-detected liquid and the above-mentioned dual-emission fluorescent probe; the ratio of the second fluorescence intensity to the first fluorescence intensity is substituted into a linear equation of the ratio and the cresyl phosphate concentration, and the cresyl phosphate concentration in the second solution is obtained, so that the cresyl phosphate concentration in the to-be-detected liquid is obtained.

[0050] The following takes the dual-emission fluorescent probe prepared with the content of Al(NO3)3·9H2O being 0.6 mmol, the content of H2TCPP being 0.2 mmol, the hydrothermal temperature being 180℃, and the hydrothermal time being 16 hours as an example to further illustrate the beneficial effects of the application.

[0051] Figure 1 The XRD pattern of the dual-emission fluorescent probe for detecting tricresyl phosphate of this invention was obtained using an EMPYREAN X-ray diffractometer from Panaco, Netherlands. Figure 1 As shown, the peaks of the dual-emission fluorescent probe at 2θ = 7.6° and 13.7° correspond to the (201) and (110) crystal planes of CCDC#1500441.

[0052] Figure 2 The image shows the FT-IR spectrum of the dual-emission fluorescent probe for detecting tricresyl phosphate according to the present invention. The instrument used was a PerkinElmer Spectrum 2 Fourier Transform Infrared Spectrometer. Figure 2 As shown, the FT-IR spectrum exhibits characteristic peaks for OH / NH, -COO, Al-O, and C=O; among them, the peak at 3435 cm⁻¹ is [missing information]. -1 The strong absorption peak at 2925 cm⁻¹ originates from the OH / NH of the ligand. -1 The location corresponds to CH, 1606 cm. -1 and 1403cm -1 This belongs to the in-plane / out-plane stretching vibration of Al-O at 775 cm⁻¹. -1 and 1069cm -1 The peak value at 1689 cm⁻¹ confirms the coordination of Al and O atoms in the framework. Compared to H₂TCPP, the dual-emission fluorescent probe shows a higher peak value at 1689 cm⁻¹. -1 The C=O stretching at the point is severely inhibited, indicating that a large number of carboxyl groups in H2TCPP react with Al. 3+ A coordination reaction occurred.

[0053] Figure 3 This is the XPS full spectrum of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention. The instrument used was a Thermo Scientific K-Alpha X-ray photoelectron spectrometer from Thermo Fisher Scientific, Inc., USA. Figure 3 As shown, the binding energies at 74.08, 285.08, 400.08, and 532.08 eV belong to the four characteristic peaks of Al2p, C1s, N1s, and O1s, respectively. The calculated mass fractions of Al, C, N, and O in the dual-emission fluorescent probe are 3.94%, 67.28%, 6.40%, and 22.38%, respectively.

[0054] Figure 4 The graph shows the fluorescence detection results of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention at different concentrations. Figure 5 The image shows the fluorescence detection results of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention at different pH values.

[0055] Figure 6The graph shows the fluorescence detection results of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention at different reaction times.

[0056] Figure 7 The image shows the fluorescence detection results of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention at different reaction temperatures. The equipment used was an FLS-1000-STM steady-state / transient fluorescence spectrometer from Edinburgh Instruments Ltd., UK, with an excitation wavelength of 415 nm and excitation / emission slit widths of 2.0 nm. The fluorescence emission spectra were measured in the range of 600–900 nm. In the accompanying drawings of this invention, F0 represents the first fluorescence intensity, corresponding to a first solution comprising 150 μL of probe suspension, 150 μL of acetonitrile, and 1200 μL of buffer solution; F represents the second fluorescence intensity, corresponding to a second solution comprising 150 μL of probe suspension, 150 μL of tricresyl phosphate (hereinafter referred to as TCP) acetonitrile solution, and 1200 μL of buffer solution; wherein, the probe suspension is an aqueous first solution of the dual-emission fluorescent probe, and unless otherwise specified, the final concentration of the dual-emission fluorescent probe is 30 mg / L; unless otherwise specified, the final concentration of TCP is 30 μmol / L; the buffer solution is used to adjust the pH of the test solution, including sodium hydroxide-hydrochloric acid buffer (0.1 mol / L), acetate-sodium acetate buffer (0.1 mol / L), and Tris-HCl buffer (0.01 mol / L), and unless otherwise specified, the buffer solution is acetate-sodium acetate buffer, and the pH of the test solution is 3.

[0057] Figure 4 In this study, the concentration of the dual-emission fluorescent probe was optimized within the range of 10–50 mg / L, and the optimal concentration was found to be 30 mg / L. Figure 5 As shown, the detection effect in a strong acid environment is significantly better than that in a weak acid environment, and the optimal reaction pH is 3. Figure 6 As shown, immediate mixing of the dual-emission fluorescent probe and TCP produces a fluorescence enhancement response, with the best enhancement effect observed at a reaction time of 5 minutes. While the F / F0 ratio decreases slightly with increasing reaction time, the overall impact is minimal. Figure 7 As shown, the reaction temperature has a relatively small impact on the detection process, with the optimal reaction temperature being 25℃. In summary, the optimal detection conditions for TCP using the dual-emission fluorescent probe are: dual-emission fluorescent probe concentration = 30 mg / L, pH = 3, reaction time = 5 min, and reaction temperature = 25℃. The following describes the fluorescence detection of TCP under these conditions.

[0058] Figure 8 The fluorescence emission spectra of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention at different TCP concentrations are shown. Figure 9 This is a linear fit plot at 655 nm for the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention when detecting TCP.Figure 10 Linear fitting graph of the dual-emission fluorescent probe for detecting cresyl phosphate of the application at 715 nm when detecting TCP.

[0059] As shown in the figure, by linear fitting of F / F0 and TCP concentration, two linear ranges of 0.5-5 μmol / L and 5-30 μmol / L were obtained. Figures 8-10

[0060] When the emission wavelength is 655 nm, the linear equation of TCP at 0.5-5 μmol / L is y=0.102x+0.987 (R 2 =0.996), and the linear equation of TCP at 5-30 μmol / L is y=1.09x-3.95 (R 2 =0.998). When the emission wavelength is 715 nm, the linear equation of TCP at 0.5-5 μmol / L is y=0.105x+0.993 (R 2 =0.998), and the linear equation of TCP at 5-30 μmol / L is y=0.490x-0.92 (R 2 =0.997). Wherein, y is F / F0, i.e. the ratio of the second fluorescence intensity to the first fluorescence intensity, and x is the concentration of cresyl phosphate in the second solution. By the three times signal-to-noise ratio formula, the detection limit at 655 nm is calculated to be 0.103 μmol / L, and the detection limit at 715 nm is calculated to be 0.082 μmol / L, so the detection limit of the dual-emission fluorescent probe of the application for TCP is 0.082 μmol / L.

[0061] Figure 11 Test result graph of the specific recognition performance of the dual-emission fluorescent probe of the application for detecting cresyl phosphate.

[0062] Wherein, the final concentrations of all the organophosphorus pollutants are the same. As shown in the figure, Figure 11 when the organophosphorus pollutant is TCP, the fluorescence enhancement multiple is about 25 times of the blank, which is much higher than other organophosphorus compounds, showing excellent selectivity and being able to specifically recognize TCP.

[0063] Figure 12 Test result graph of the anti-interference performance of the dual-emission fluorescent probe of the application for detecting cresyl phosphate. The concentrations of Ca 2+ , Co 2+ , Mn 2+ , CO3 2- , HCO3 - , HPO4 2- in the first solution and the second solution are 1 times of the concentration of TCP, and the concentration of Ba 2+ ​Cr(Ⅵ), H2PO4 - Cl - Br - The concentration of the above-mentioned ions is 5 times the concentration of TCP. As shown in Table 1, compared with the blank, the influence of the above-mentioned ions on the system is small, which indicates that the reaction system for detecting TCP by using the dual-emission fluorescent probe has good anti-interference ability, and it is feasible to apply the dual-emission fluorescent probe to the detection of TCP in actual water samples. Figure 12

[0064] The detection method of the present application was used to detect TCP in tap water and lake water. All the actual water samples were collected from Xipu campus of Southwest Jiaotong University, the tap water was taken from the laboratory, and the lake water was taken from Xihu. No TCP was detected in the blank water sample, so the water sample was subjected to standard addition treatment. Before standard addition, the water sample was filtered using a 0.22 μm filter membrane. After standard addition, the standard-added water sample (i.e. a mixture of the acetonitrile solution of TCP and the water sample) was obtained. Then, the fluorescence emission spectrum of 150 μL of the probe suspension, 150 μL of the standard-added water sample and 1200 μL of the first solution (the concentration of TCP in the first solution was 0 μmol / L) of acetic acid-sodium acetate buffer was tested, i.e. F0 was obtained; the fluorescence emission spectrum of 150 μL of the probe suspension, 150 μL of the standard-added water sample and 1200 μL of the second solution (the concentration of TCP in the second solution was 5, 15 and 30 μmol / L, respectively) of acetic acid-sodium acetate buffer was tested, i.e. F was obtained. Then, the content of TCP in the standard-added water sample was calculated by using the linear fitting equation, and the results are shown in Table 3.

[0065] Table 1

[0066]

[0067] As shown in Table 1, the recovery rate of the standard-added sample was 95-105%, and the RSD was less than 1.22%. Therefore, the detection method of the present application for detecting cresyl phosphate has good accuracy and reproducibility, and has potential application in the field of environmental analysis.

[0068] In order to explore the fluorescence enhancement mechanism, the XPS fine spectrum and SEM photograph of the dual-emission fluorescent probe before and after use were tested.

[0069] Figure 13 The XPS fine spectrum of C1s of the dual-emission fluorescent probe for detecting cresyl phosphate before and after use of the present application. Figure 14 The XPS fine spectrum of N1s of the dual-emission fluorescent probe for detecting cresyl phosphate before and after use of the present application. Figure 15 The XPS fine spectrum of P2p of the dual-emission fluorescent probe for detecting cresyl phosphate before and after use of the present application. Figure 16 ​XPS fine spectra of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention before and after use at Al2p. Figure 17 The XPS fine spectra of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention before and after use at O1s are shown.

[0070] exist Figure 13 In the figure, the binding energies at 288.68 eV, 285.68 eV, and 284.58 eV correspond to the C=O, CO / CN, and CC / C=C of the dual-emission fluorescent probe before use, respectively. After use, the CO / CN characteristic peak shows a significant blue shift. Figure 14 In the figure, the binding energies at 399.88 eV and 397.68 eV correspond to the CN and C=N values ​​of the dual-emission fluorescent probe before use, respectively; after use, the peak positions remain almost unchanged. Figure 15 Before use, no characteristic peaks related to P were found. After use, the binding energies at 135.08 eV and 134.18 eV corresponded to P2p, respectively. 1 / 2 and P2p 3 / 2 This indicates that an interaction occurred between the dual-emission fluorescent probe and the TCP. Figure 16 In the figure, the binding energies at 74.88 eV and 74.18 eV correspond to the Al2p of the dual-emission fluorescent probe before use, respectively. 1 / 2 and Al2p 3 / 2 This can be attributed to the Al-O cluster coordinated with the carboxyl group in the H2TCPP ligand of the dual-emission fluorescent probe; after TCP adsorption, the Al2p binding energy decreased to 74.58 eV and 74.08 eV, indicating that electron transfer occurred in the Al2p valence band, forming an Al-OP complex. Figure 17 In the study, four peaks were observed, which belong to the used dual-emission fluorescent probe: OC=O (533.28 eV), POH (532.48 eV), Al-O (530.18 eV), Al-OP, and P=O (531.08 eV), respectively. This indicates that the dual-emission fluorescent probe and TCP formed an Al-OP coordination bond through ligand exchange.

[0071] Figure 18 This is a SEM image of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention before use. Figure 19 This is a SEM image of the dual-emission fluorescent probe for detecting tricresyl phosphate of the present invention after use.

[0072] like Figures 18-19As shown, the surface of the dual-emission fluorescent probe before the reaction is smooth and has a plate-like crystal morphology. After the reaction, the aggregated nanoparticles make the surface rough, indicating that a large number of TCP molecules are adsorbed on the crystal surface. The dual-emission fluorescent probe after use has an intact structure, indicating that the bonds between the Al-O cluster and the carboxyl group can be partially broken or rearranged without structural collapse.

[0073] In summary, the π-π stacking interaction between the benzene ring of TCP and the aromatic ring on the backbone ligand of the dual-emission fluorescent probe promotes ligand exchange between TCP and the carboxyl group. That is, the Al-O cluster of the dual-emission fluorescent probe coordinates with the phosphate ester group of TCP, and the resulting Al-OP interaction restricts the LMCT effect of the probe, thus leading to the fluorescence enhancement of the dual-emission fluorescent probe.

[0074] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A method for detecting tricresyl phosphate, characterized in that: Includes the following steps: Obtain a first fluorescence intensity, wherein the first fluorescence intensity is the fluorescence intensity of a first solution comprising the dual-emission fluorescent probe; Obtain the second fluorescence intensity, which is the fluorescence intensity of a second solution comprising the test liquid and the dual-emission fluorescent probe; Substituting the ratio of the second fluorescence intensity to the first fluorescence intensity into the linear equation between the ratio and the concentration of tricresyl phosphate, the concentration of tricresyl phosphate in the second solution is obtained, thereby obtaining the concentration of tricresyl phosphate in the liquid to be tested. The XPS full spectrum of the dual-emission fluorescent probe shows characteristic peaks of Al2p, C1s, N1s, and O1s; the FT-IR spectrum shows characteristic peaks of OH / NH, -COO, Al-O, and C=O; and the fluorescence spectrum shows dual emission wavelengths. The preparation method of the dual-emission fluorescent probe includes the following steps: An aqueous solution comprising aluminum salt and porphyrin is prepared according to a ratio of 0.4–0.8 mmol Al(NO3)3•9H2O and 0.1–0.3 mmol tetrakis(4-carboxyphenyl)porphyrin per 30 mL of aqueous solution; The aqueous solution is loaded into a reaction vessel for hydrothermal reaction; After the hydrothermal reaction is complete, the precipitate is collected and washed to obtain a dual-emission fluorescent probe for detecting tricresyl phosphate.

2. The method for detecting tricresyl phosphate as described in claim 1, characterized in that: The hydrothermal reaction temperature is 160–200 °C, and the reaction time is 12–20 hours.

3. The method for detecting tricresyl phosphate as described in claim 1, characterized in that: The precipitate was washed with DMF and methanol.

4. The method for detecting tricresyl phosphate as described in claim 1, characterized in that: The excitation wavelength was 415 nm, the concentration of the dual-emission fluorescent probe in the first and second solutions was 28–32 mg / L, and the detection limit of tricresyl phosphate was 0.082 μmol / L.

5. The method for detecting tricresyl phosphate as described in claim 4, characterized in that: When the emission wavelength is 655 nm, the linear equation for tricresyl phosphate concentrations of 0.5–5 μmol / L is y = 0.102x + 0.987, and the linear equation for tricresyl phosphate concentrations of 5–30 μmol / L is y = 1.09x - 3.95, where y is the ratio of the second fluorescence intensity to the first fluorescence intensity, and x is the concentration of tricresyl phosphate in the second solution.

6. The method for detecting tricresyl phosphate as described in claim 4, characterized in that: When the emission wavelength is 715 nm, the linear equation for tricresyl phosphate concentrations of 0.5–5 μmol / L is y = 0.105x + 0.993, and the linear equation for tricresyl phosphate concentrations of 5–30 μmol / L is y = 0.490x - 0.920, where y is the ratio of the second fluorescence intensity to the first fluorescence intensity, and x is the concentration of tricresyl phosphate in the second solution.

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