Perylene tetracarboxylic acid-Zn < 2 + > complex fluorescent probe for early warning of algae outbreak as well as preparation method and application thereof

Abstract

The invention discloses a perylene tetracarboxylic acid-Zn < 2 + > complex fluorescent probe for early warning of algae outbreak and a preparation method and application thereof. 3, 4, 9, 10-perylenetetracarboxylic acid is used as a fluorescent ligand and is coordinated with Zn < 2 + > to form a perylenetetracarboxylic acid-Zn < 2 + > complex probe, the fluorescence of the perylenetetracarboxylic acid-Zn < 2 + > complex is weak, the complex fluorescent probe is decomplexed based on the stronger complexing ability of PO4 < 3-> and Zn < 2 + >, then fluorescence is recovered, and the purpose of detecting PO4 < 3-> is achieved. The probe shows an excellent selective response characteristic on PO4 < 3-> in water, and the detection limit of the probe can reach 0.052 mg / L. The invention also provides detection test paper which can realize on-site visual detection of PO4 < 3-> in a water sample, has the advantages of high detection sensitivity, simplicity and convenience in operation, low cost and high response speed, can monitor phosphate pollution in an environmental water body and algae outbreak caused by the phosphate pollution, and has an important application prospect.

Description

Technical Field

[0001] The present invention relates to the field of environmental pollution detection, and in particular to a perylenetetracarboxylic acid-Zn-Hydroxyphosphate (P-Hydroxyphosphate) for detecting phosphate. 2+ Complex fluorescent probe and preparation method thereof. Background Art

[0002] As one of the most important elements for life on Earth, phosphorus is closely related to population growth and the rapid development of industrialization. In recent years, with the improvement of industrialization level, the phosphorus content in industrial wastewater has increased. The phosphorus in industrial wastewater is mainly in the form of phosphate (PO4 3- ) and can be reused by organisms. The discharge of high-phosphate wastewater into water bodies stimulates algae growth, which depletes oxygen in the water and causes eutrophication. The resulting algae outbreaks (such as blue-green algae, green algae, red tides, etc.) in water bodies (such as rivers, lakes and seawater) will cause multiple hazards to ecosystems, human health and economic activities: (1) Ecological hazards: After the algae reproduce in large quantities, they die and decompose, consuming a large amount of oxygen in the water, causing fish, shellfish and other aquatic organisms to suffocate and die; the toxins released by toxic algae or the lack of oxygen in the water will directly kill aquatic organisms, disrupt the food chain, and cause the imbalance of the ecosystem. (2) Human health hazards: The toxins produced by certain algae (such as microcystis in blue-green algae and dinoflagellates in seawater) (such as microcystins, ciguatera toxins, paralytic shellfish poisoning) can harm humans through drinking water, seafood or skin contact, causing liver damage, nervous system damage, diarrhea, vomiting, and long-term exposure may increase the risk of cancer. (3) Economic and social harm: The mass death of fish causes a reduction in fishery production, and the accumulation of algae causes foul odor and discoloration in the water, affecting the landscape and leisure activities (such as swimming and fishing). Cleaning up algal blooms and restoring the ecology requires huge amounts of money. (4) Long-term environmental problems: Algae blooms are the result of eutrophication (excessive nitrogen and phosphorus), and the death and decomposition of algae release nutrients, forming a vicious cycle. The decomposition process of algae may release potent greenhouse gases such as methane and hydrogen sulfide. Therefore, it is of great significance to design and develop a phosphate detection probe with high efficiency and high sensitivity to achieve visual detection of phosphate and thus provide early warning of algae blooms.

[0003] Traditional PO4 3-Detection techniques, such as colorimetry, titration, inductively coupled plasma optical emission spectrometry (ICP-OES), and ion chromatography, although widely used in the field of analytical chemistry, still have many limitations, including high detection costs, long detection times, complex operation procedures, and susceptibility to various interference factors. In addition, although fluorescent sensors have shown certain potential in the field of ion detection, they still face significant challenges in the direct detection of anions. Therefore, the development of a new detection method that can achieve high sensitivity and specific recognition of phosphate remains an important scientific problem that needs to be solved in the current field of analytical chemistry.

[0004] In recent years, fluorescent sensing technology based on organic small molecules has attracted widespread attention in the field of environmental pollutant detection. For example, Chinese patent CN1090209117A "Fluorescent molecular probe for identifying phosphate ions in water environment and its preparation method" uses 2-hydroxy-1-naphthaldehyde and 2-aminobenzenethiol to synthesize fluorescent probe L. In 50% methanol aqueous solution, the probe is converted to enol form due to intramolecular proton transfer in the excited state. When phosphate ions are added, due to the weak interaction between the fluorescent molecular probe and the phosphate ions, it is finally converted to a more stable keto structure, forming a conjugated structure, generating fluorescence, and achieving PO4 3- The purpose of detection. But the probe L recognizes PO4 3- It is only speculated that the structural transformation is caused by "weak interaction", and the specific mechanism of action has not been elucidated. The sensitivity is low, and the probe must be used in an environment with a high solvent content (50% methanol). These characteristics make it difficult for the probe to accurately detect phosphate in water bodies (such as river water, lake water and sea water), and therefore it is impossible to monitor and warn of algae outbreaks in water bodies. Chinese patent CN111943887A "A fluorescent probe for highly selective identification of phosphate, preparation method and application" designed a quinoline compound as a detector for PO4 3- The fluorescent probe has good selectivity and a low detection limit, but it needs to be carried out in a specific volume ratio (3:7) of ethanol and water. That is, the probe needs to be used in an environment with a high solvent content (ethanol content of 30%). In addition, it needs to be left to stand for 40 minutes to achieve a stable fluorescence signal during detection, which is difficult to meet the real-time and rapid monitoring needs on site, and may have disadvantages in rapid detection scenarios. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the existing technology, to provide a perylenetetracarboxylic acid-ZnO2 for early warning of algae outbreaks, and to solve the technical problems of the existing phosphate ion detection method, such as insufficient sensitivity, complex operation, and the need for a high-content solvent environment. 2+ Complex fluorescent probe and its preparation method and application.

[0006] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0007] The present invention provides a perylenetetracarboxylic acid-Zn for early warning of algae outbreaks 2+ Complex fluorescent probe, the fluorescent probe is perylenetetracarboxylic acid-Zn 2+ Complex fluorescent probe (abbreviated as [PTCA-Zn 2+ ]), the molecular structure is as follows:

[0008]

[0009] A method for detecting PO4 3- Perylenetetracarboxylic acid-Zn 2+ The preparation method of the complex fluorescent probe and the synthetic route are as follows:

[0010]

[0011] The present invention provides a method for detecting PO4 3- Perylenetetracarboxylic acid-Zn 2+ The preparation method of the complex fluorescent probe specifically comprises the following steps:

[0012] Perylene tetracarboxylic acid (PTCA) was added to a mixed solvent of water and dimethyl sulfoxide (DMSO), and NaOH solid was added and stirred to react until completely dissolved to obtain PTCA solution. Zinc salt was added and stirred at room temperature to obtain [PTCA-Zn 2+ ] complex dispersion. After the reaction is completed, the mixture is allowed to stand, the supernatant is skimmed off, and a yellow solid is obtained by rotary evaporation. Then, the precipitate is washed with anhydrous ethanol and vacuum dried to finally obtain a yellow powdery solid, which is [PTCA-Zn 2+ ] complex fluorescent probe.

[0013] Preferably, the volume ratio of DMSO to water is 1:(5-4).

[0014] Preferably, the mass percentage concentration of NaOH in the mixed solvent of DMSO and water is 0.4-0.8%.

[0015] Preferably, the zinc salt is any one of zinc chloride, zinc sulfate and zinc nitrate.

[0016] Preferably, the vacuum drying temperature is 25-40° C. and the time is 8-12 h.

[0017] The present invention also provides a perylenetetracarboxylic acid-Zn 2+ The test paper made of complex fluorescent probe can be identified by naked eyes under ultraviolet light, thus visually detecting the application of glyphosate. The specific steps include the following:

[0018] (1) Immerse the blank cellulose test strip in PTCA stock solution and let it dry naturally;

[0019] (2) The test strip dried in step (1) is immersed in a zinc ion solution and naturally dried.

[0020] The perylenetetracarboxylic acid-Zn provided by the present invention 2+ Complex fluorescent probes have the following outstanding advantages:

[0021] (1) Breaking through the sensitivity limitation of traditional detection methods, the detection limit is lower than the standard limit of "Surface Water Environmental Quality (GB 3838-2002)" and "Drinking Water Quality Standard (GB 5749-2022)".

[0022] (2) The probe has excellent water solubility / dispersibility and can respond sensitively to phosphate in water.

[0023] (3) Utilize the “competitive coordination” detection mechanism to improve the ability of selective recognition.

[0024] (4) Develop a portable test strip test format to achieve an effective combination of laboratory testing and on-site monitoring. The developed portable fluorescent test strip can observe obvious fluorescence differences under a portable 365nm ultraviolet lamp, allowing "naked eye" identification.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) Specific recognition function: [PTCA-Zn 2+ ]PO4 3- It has a selective response, showing a linear fluorescence enhancement effect in the concentration range of 0-210 μmol / L, and a minimum detection limit of 0.052 mg / L (0.017 mg / L as P), which is lower than the standard limit for Class V waters in the "Surface Water Environmental Quality Standard (GB 3838-2002)" and Class II seawater quality in the "Seawater Quality Standard (GB 3097-1977)". Therefore, it can be used for early warning of algae outbreaks in water bodies;

[0027] (2) Rapid response characteristics: can be in contact with PO4 3- Complete the test within 100 seconds;

[0028] (3) Stabilization mechanism: Fluorescence spectroscopy analysis, Job's Plot curve verification and UV-visible / infrared spectroscopy characterization confirmed that PO4 3- The perylene tetracarboxylic acid molecules are replaced through "competitive complexation" to trigger the "on-off-on" change of the system's fluorescence. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 In the embodiment, PTCA and the complex [PTCA-Zn 2+ ]Infrared spectrum of solid powder.

[0030] Figure 2 The complex [PTCA-Zn 2+ ] and fluorescence spectra of different anions.

[0031] Figure 3 In the presence of different anions in the examples, PO4 was added 3- Pre- and post-complex [PTCA-Zn 2+ ]Fluorescence intensity at 486 nm.

[0032] Figure 4 The complex [PTCA-Zn 2+ ] dispersion at different concentrations of PO4 3- Fluorescence spectra in the presence of .

[0033] Figure 5 The complex [PTCA-Zn 2+ ]The fluorescence intensity of the dispersion is related to PO4 3- Linear relationship with concentration.

[0034] Figure 6 In the embodiment [PTCA-Zn 2+ ] Detection of PO4 3- response time.

[0035] Figure 7 The probe [PTCA-Zn 2+ ] and PO4 3- The interaction ratio.

[0036] Figure 8 In the embodiment [PTCA-Zn 2+ Fluorescent test strips to detect PO4 3- Fluorescence color change diagram.

[0037] Figure 9 In the embodiment [PTCA-Zn 2+ Fluorescent test strips to detect PO4 3- Grayscale image of fluorescence color change. DETAILED DESCRIPTION

[0038] The detailed description of the technical solution of the present invention will be explained in conjunction with the drawings and specific implementation methods of the specification. It should be noted that the implementation cases listed below are only exemplary embodiments of the technical solution of the present invention and do not constitute a restrictive interpretation of the scope of protection of the present invention. Any other embodiments obtained by ordinary technicians in this field without making creative work based on the core technical solution of the present invention without departing from the design concept of the present invention shall fall within the scope of protection defined by the claims of the present invention.

[0039] Unless otherwise specified in the specific embodiments, the experimental methods involved in the embodiments of the present invention all adopt the general standard operating procedures in the field, and the experimental materials, chemical reagents, etc. used are purchased through commercial channels and meet the analytical or chemical purity level.

[0040] Example 1 Configuration of various stock solutions and test solutions

[0041] Zn 2+ Preparation of stock solution: 80.7 mg of ZnSO4 solid was accurately weighed and dissolved in 5 mL of deionized water to prepare a ZnSO4 stock solution with a concentration of 100 mmol / L. 2+ Stock solution.

[0042] Preparation of various anion stock solutions: Accurately weigh 10.6 mg (K3PO4), 7.1 mg (Na2HPO4), 6.0 mg (NaH2PO4), 6.0 mg (KBr), 2.9 mg (NaCl), 2.9 mg (KF), 8.3 mg (KI), 4.2 mg (NaHCO3), 4.2 mg (NaNO3), 4.1 mg (CH3COONa), 4.4 mg (NaH2PO2), 6.3 mg (Na2SO3), and 4.0 mg (NaHS) solids and dissolve them in 5 mL of deionized water to prepare anion stock solutions with a concentration of 10 mmol / L.

[0043] Example 2

[0044] Accurately weigh 0.21g of NaOH solid and dissolve it in 50mL of a mixed solvent of water and DMSO (V(DMSO):V(H2O)=1:4, NaOH concentration is 0.4%). Add 21.41mg of PTCA solid to the above solution and stir the reaction at room temperature until it is completely dissolved to prepare a PTCA stock solution with a concentration of 1.0mmol / L. Then add 0.12g (36.25mmol / L, n(PTCA):n(Zn 2+ )=1:36.25) of zinc sulfate solid, stirred at room temperature for 5 min, and obtained [PTCA-Zn 2+After the reaction was completed, the mixture was allowed to stand for 10 minutes, the supernatant was removed, the precipitate was washed with anhydrous ethanol, the ethanol was removed by rotary evaporation, and the mixture was dried at 25°C for 8 hours to obtain [PTCA-Zn 2+ ] Complex fluorescent probe 19.72 mg (yield 88.72%), yellow solid powder.

[0045] The solid powder was used to obtain [PCTA-Zn 2+ ] complex FTIR data, such as Figure 1 As shown, 3445cm -1 The OH vibration absorption peak of PCTA is 1772 cm -1 The C=O stretching vibration absorption peak of PCTA is 1302 cm -1 and 1235cm -1 are respectively attributed to the COC stretching vibration absorption peak; however, when Zn 2+ After, 1772cm -1 The C=O stretching vibration absorption peak at 1302 cm -1 and 1235cm -1 The COC stretching vibration absorption peak disappears completely, and the peak at 1362 cm -1 A new absorption peak appears at -COO - The symmetrical stretching vibration absorption peak is at 3445 cm -1 A strong OH vibration absorption peak also appeared at the 2+ The complex was successfully formed with PCTA, and the complex [PCTA-Zn 2+ ]The solid powder contains water of crystallization.

[0046] Example 3

[0047] Accurately weigh 0.42g of NaOH solid and dissolve it in 50mL of a mixed solvent of water and DMSO (V(DMSO):V(H2O)=1:5, NaOH concentration is 0.8%). Add 42.82mg of PTCA solid to the above solution and stir the reaction at room temperature until it is completely dissolved to prepare a PTCA stock solution with a concentration of 1.50mmol / L. Then add 0.19g (60.00mmol / L, n(PTCA):n(Zn 2+ )=1:40) of zinc sulfate solid, stirred at room temperature for 7 minutes to obtain [PTCA-Zn 2+ After the reaction was completed, the mixture was allowed to stand for 10 minutes, the supernatant was removed, the precipitate was washed with anhydrous ethanol, the ethanol was removed by rotary evaporation, and the mixture was dried at 30 ° C for 6 hours to obtain [PTCA-Zn 2+ ] Complex fluorescent probe 29.73 mg (yield 89.15%), yellow solid powder.

[0048] The FTIR test results of the fluorescent probe in this example are consistent with the test results in Example 2.

[0049] Example 4

[0050] Accurately weigh 0.32g of NaOH solid and dissolve it in 50mL of a mixed solvent of water and DMSO (V(DMSO):V(H2O)=1:4.5, NaOH concentration is 0.6%). Add 32.12mg of PTCA solid to the above solution and stir the reaction at room temperature until it is completely dissolved to prepare a PTCA stock solution with a concentration of 2.00mmol / L. Then add 0.33g (100.00mmol / L, n(PTCA):n(Zn 2+ )=1:50) of zinc sulfate solid, stirred at room temperature for 10 min to obtain [PTCA-Zn 2+ After the reaction was completed, the mixture was allowed to stand for 10 minutes, the supernatant was removed, the precipitate was washed with anhydrous ethanol, the ethanol was removed by rotary evaporation, and the mixture was dried at 40 ° C for 7 hours to obtain [PTCA-Zn 2+ ] Complex fluorescent probe 38.39 mg (yield 86.34%), yellow solid powder.

[0051] The FTIR test results of the fluorescent probe in this example are consistent with the test results in Example 2.

[0052] Example 5 [PTCA-Zn 2+ ]PO4 3- Selectivity and anti-interference

[0053] PTCA was dissolved in a mixture of DMSO and deionized water (V(DMSO):V(H2O)=1:4) in a centrifuge tube. Then 14.5μL of Zn 2+ The stock solution was added to the above centrifuge tubes, and then 100 μL (500 μmol / L) of anion stock solution was added to each of them. The total volume of the final mixed solution was 2 mL. After standing for 5 minutes, the fluorescence emission spectrum was tested in a fluorescence spectrometer. The results are as follows Figure 2 As shown, when PO4 is added 3- After that, the fluorescence intensity at 486nm increased 540 times, HPO4 2- 、H2PO4 - and H2PO2 - Under the same conditions, there will be weak fluorescence recovery, but compared with PO4 3- This indicates that [PTCA-Zn 2+ ] Detection of PO4 3- The selectivity is better.

[0054] Dissolve PTCA in a mixture of DMSO and deionized water (V(DMSO):V(H2O)=1:4) in a centrifuge tube. Use a pipette to draw 14.5 μL of Zn 2+ The stock solution was added to the above centrifuge tubes, and then 100 μL (500 μmol / L) PO4 3- Then, 100 μL (500 μmol / L) of other anion test solutions were added sequentially. The total volume of the final mixed solution was 2 mL. After standing for 5 minutes, the fluorescence intensity at 486 nm was measured in a fluorescence spectrometer. The results were as follows: Figure 3 As shown in the figure, all mixed solutions showed significant fluorescence response and the fluorescence intensity was basically consistent, indicating that [PTCA-Zn 2+ ] Detection of PO4 3- The anti-interference performance is better.

[0055] Example 6 [PTCA-Zn 2+ ] Detection of PO4 3- Detection limit

[0056] PTCA was dissolved in a mixed solvent of DMSO and deionized water (V(DMSO):V(H2O)=1:4) in a centrifuge tube. 14.5μL of Zn 2+ Stock solution, then add 5μL, 10μL, 15μL, 20μL until 100μL of PO4 3- Stock solution, the total volume of the final mixed solution is 2mL, PO4 3- The final concentration is 0-500 μmol / L. After standing for 5 minutes, the fluorescence emission spectrum is tested in a fluorescence spectrometer. The results are as follows Figure 4 As shown, with PO4 3- With the increase of concentration, the fluorescence intensity of the solution at 486 nm gradually increased, and the fluorescence spectrum morphology was consistent with that of PTCA solution.

[0057] Then repeat the above operation, set a smaller concentration gradient in the concentration range of 0-210μmol / L, and measure the fluorescence intensity at 486nm in the fluorescence spectrometer. Linear fitting is performed on these data points, and the results are as follows: Figure 5 As shown, the linear equation is y = 1.21x + 5.46, R 2 =0.99676, PO4 is calculated by the detection limit formula 3-The detection limit LOD is 0.052 mg / L. According to the formula total phosphorus content (in terms of P) = phosphate content × (31 / 95), the detection limit calculated as total phosphorus content is 0.017 mg / L, which is lower than the total phosphorus content standard (0.4 mg / L) for Class V waters in the "Surface Water Environmental Quality Standard (GB 3838-2002)" and the active phosphate (in terms of P) standard limit of 0.03 mg / L for Class II seawater quality in the "Seawater Quality Standard (GB 3097-1977)". Therefore, the probe can give early warning of algae outbreaks in water bodies, which shows that [PTCA-Zn 2+ ] Complex detection PO4 3- With high sensitivity, PO4 3- Trace detection.

[0058] Example 7 [PTCA-Zn 2+ ] Detection of PO4 3- Response time

[0059] PTCA was dissolved in a mixed solvent of DMSO and deionized water (V(DMSO):V(H2O)=1:4) in a quartz cuvette. 500μL of DMSO and 1342μL of deionized water were added, and 18μL of Zn 2+ Stock solution, shake well to completely quench the fluorescence of the solution, and then add 100 μL of PO4 3- The stock solution was quickly shaken and placed in a fluorescence spectrometer to test the change in fluorescence intensity of the solution over time. The results were as follows: Figure 6 As shown in the figure, the fluorescence intensity of the mixed solution increased rapidly from 0 to 50 seconds, and then the growth rate gradually slowed down and remained basically stable after 100 seconds, which indicated that the complex [PTCA-Zn 2+ ] can achieve PO4 3- Rapid detection.

[0060] Example 8 [PTCA-Zn 2+ ] and PO4 3- The interaction ratio

[0061] In 17 centrifuge tubes, PTCA was dissolved in a mixed solvent of DMSO and deionized water (V(DMSO):V(H2O)=1:4). Then Zn 2+ The stock solution makes the PTCA and Zn in the final solution 2+ The concentration ratio is 1:36.25, and then 4μL, 8μL, 10μL, 12μL... 36μL of PO4 are added to the above centrifuge tube in sequence. 3- The total volume of the final mixed solution was 2 mL, and a series of [PO4 3- ] / ([PO43- ]+[PTCA-Zn 2+ The complex titration test solution with the value of 0.1, 0.15, 0.2, 0.25 ... 0.9 was used to test the fluorescence intensity at 486nm in a fluorescence spectrometer, and the [PTCA-Zn 2 + ] and PO4 3- The Job's Plot curve is as follows Figure 7 As shown in the figure, an inflection point appears at X = 0.53, indicating that the probe [PTCA-Zn 2+ ] and PO4 3- The interaction ratio is 1:1.

[0062] Example 9 [PTCA-Zn 2+ ] PO4 in the actual water sample spiked with the sample 3- Detection applications

[0063] The water sample collection and pretreatment methods are as follows: tap water supplied by the laboratory, drinking purified water, surface water (0-20cm depth) of West Lake in Wushan Campus of South China University of Technology, and simulated seawater samples prepared with sea salt were collected respectively. The sample pretreatment adopts the centrifugation-filtration method: first, the tap water sample is subjected to gradient centrifugation separation (3000-4000 rpm, for 5-10 minutes), and then the supernatant after centrifugation is separated into solid and liquid by qualitative filter paper to remove suspended particulate matter. PO4 is used. 3- Preparation method of stock solution: the above three pre-treated water samples were used as solvents, and 10mmol / L PO4 3- Stock solution. Dissolve PTCA in a mixture of DMSO and deionized water (V(DMSO):V(H2O)=1:4) in a centrifuge tube. Add 14.5μL of Zn 2+ Stock solution, sequentially add 10μL, 20μL, 30μL, 40μL of PO4 of different water samples 3- Stock solution, get 4 groups of PO4 3- The concentrations of the spiked test solution were 50 μmol / L, 100 μmol / L, 150 μmol / L, and 200 μmol / L. Four parallel experiments were performed in each group. The fluorescence intensity of the spiked test solution at 486 nm was measured using a fluorescence spectrometer. According to the formula y = 1.21x + 5.46 (x is PO4 3- The concentration of PO4 in the spiked test solution was calculated. 3- The recovery rate and relative standard deviation were calculated, and the results are shown in Table 1.

[0064] Table 1[PTCA-Zn 2+ ] PO4 in the actual water sample spiked with the sample 3- Detection

[0065]

[0066] Note: PO4 was not detected in the actual water samples 3- .

[0067] Example 10 [PTCA-Zn 2+ Preparation of fluorescent test paper and its application in PO4 3- Detection

[0068] The filter paper strips were soaked in 1 mM PCTA solution for 10 min and dried naturally to prepare the test paper loaded with PTCA. 2+ The fluorescent test strips were prepared by adding 500μmol / L PO4 3- Drop the solution onto the fluorescent test strip, illuminate the test strip with a 365nm handheld UV lamp, and observe the change in the fluorescent color of the test strip. The results are as follows: Figure 8 and Figure 9 As shown. Under 365nm ultraviolet light, PTCA test paper emits bright lake blue fluorescence; PTCA and Zn 2+ Complex formation [PTCA-Zn 2+ ] detection test strip, its fluorescence is quenched, and the test strip only shows the blue-purple light of the ultraviolet lamp; then, in [PTCA-Zn 2+ ] Add PO4 to the test strip 3- After solution, the test strips emitted bright green fluorescence. These results indicate that [PTCA-Zn 2+ ] Fluorescent test strips can detect PO4 in actual samples 3- Potential for convenient visual monitoring.

[0069] The principle of the present invention: 3,4,9,10-perylenetetracarboxylic acid is a perylene polycyclic aromatic hydrocarbon derivative with a rigid planar conjugated structure. In alkaline solution, the carboxylic acid group (-COOH) is deprotonated to become a carboxylate radical (-COO - ), the negative charge is delocalized to the entire molecule through the conjugation effect, further enhancing the delocalization of π electrons and reducing the probability of non-radiative transitions (such as vibrational relaxation and internal conversion). The deprotonated molecule has higher symmetry and planarity, and the efficiency of releasing energy through radiative transition (luminescence) is higher, thereby increasing the fluorescence quantum yield. In addition, under alkaline conditions, the hydrophilicity of the carboxylate group is enhanced, the molecule has better solubility in water, and the fluorescence quenching caused by aggregation (ACQ effect) is reduced, so that the molecule is in a single-molecule luminescent state and the fluorescence is significantly enhanced. Zn 2+After coordinating with the carboxylate of PTCA, it will promote the formation of nano-aggregates of PTCA molecules, resulting in the dissipation of excited state energy through intermolecular interactions (such as π-π stacking), triggering the ACQ effect, and thus quenching fluorescence. 3- With Zn 2+ It has a strong coordination effect and can capture [PTCA-Zn 2+ ] in Zn 2+ , releasing PTCA molecules to restore their fluorescence. Through this "competitive complexation" method, the change of fluorescence signal can be more intuitively seen, thus achieving rapid and sensitive detection of PO4 3- purpose.

[0070] The above examples are preferred implementations of the present invention, but the implementation of the present invention is not limited to the above examples. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A perylenetetracarboxylic acid-Zn for early warning of algae outbreaks 2+ The complex fluorescent probe is characterized by: The structural formula of the fluorescent probe is as follows:

2. A perylenetetracarboxylic acid-ZnO for early warning of algae outbreaks according to claim 1 2+ The method for preparing a complex fluorescent probe is characterized in that: The synthetic route is as follows:

3. The preparation method according to claim 2, characterized in that The following steps are involved: Perylene tetracarboxylic acid is added to a mixed solvent of water and dimethyl sulfoxide, and solid sodium hydroxide is added and stirred until completely dissolved to obtain a perylene tetracarboxylic acid solution. Zinc salt is added and stirred at room temperature to obtain perylene tetracarboxylic acid-Zn 2+ After the reaction is completed, the mixture is allowed to stand, the supernatant is removed, and a yellow solid is obtained by rotary evaporation; then, the precipitate is washed with anhydrous ethanol and vacuum dried to obtain a yellow powdery solid, which is perylenetetracarboxylic acid-Zn 2+ Complex fluorescent probe.

4. The preparation method according to claim 3, characterized in that The zinc salt includes any one of zinc chloride, zinc sulfate and zinc nitrate.

5. The preparation method according to claim 3, characterized in that The volume ratio of water to dimethyl sulfoxide is (5-4):

1.

6. The preparation method according to claim 3, characterized in that The mass fraction of the sodium hydroxide in the perylenetetracarboxylic acid solution is 0.4-0.8%.

7. The preparation method according to claim 3, characterized in that The stirring reaction time is 5 to 10 minutes.

8. The preparation method according to claim 3, characterized in that The vacuum drying temperature is 25-40° C. and the time is 6-8 hours.

9. Perylenetetracarboxylic acid-Zn according to claim 1 2+ Complex fluorescent probe in detecting PO4 3- Application in.

10. A portable fluorescent probe test paper, characterized in that: The preparation method comprises the following steps: soaking a filter paper strip in the perylenetetracarboxylic acid solution of claim 3, drying the strip naturally, and preparing a test paper loaded with perylenetetracarboxylic acid; and then soaking the test paper in the zinc salt solution of claim 3, and drying the strip naturally to prepare perylenetetracarboxylic acid-Zn 2+ Complex fluorescent test paper can be used to visually identify and detect PO4 under ultraviolet light 3- .

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