A doped polymer dot, its preparation method and application

Abstract

The present invention discloses a doped polymer dot and its preparation method and application. A derivative of hydrophobic ruthenium bipyridine is used as a doped dye, and a polymer dot with a self - contained coreactant is used as an encapsulation body. The doped polymer dot Ru@Pdots is prepared by a nanoprecipitation method. In the present invention, self - enhanced polymer dots - Ru@Pdots are synthesized by introducing an intramolecular electron transfer and an intermolecular resonance energy transfer process. Ru@Pdots is used as a self - enhanced ECL probe to fabricate an ECL imaging array capable of visual detection. When iodine in the detection solution is oxidized, the nitrogen free radicals on the side chain of Ru@Pdots are consumed, thus quenching the ECL of Ru@Pdots. This method not only realizes the visual detection of iodine content in natural seawater, but also provides ideas and possibilities for detecting radioactive substances in nuclear pollution.

Description

Technical Field

[0001] The present invention relates to a polymer dot for high-throughput iodide detection, and particularly to a doped polymer dot, a preparation method thereof and an application thereof. Background Art

[0002] Although nuclear energy can provide large-scale electricity without generating greenhouse gases, the operation of nuclear power plants and potential nuclear accidents may release a large amount of radionuclides, thus causing great and irreversible damage to the global marine environment and biological health. If a large amount of radioactive nuclides that have not been effectively treated, such as iodine-129, iodine-131, etc., are discharged into the ocean, these radioactive iodine isotopes will enter the ecosystem through the air or water body, and then gradually accumulate in the food chain, thus threatening human health and even increasing the risk of cancer. Therefore, designing a method for quickly and accurately determining iodide ions in the environment shows its great significance in the field of environmental public safety.

[0003] Electrochemiluminescence imaging (ECL), as a new type of visual detection technology, combines the advantages of bioimaging technology and ECL technology, and has the advantages of high throughput, high sensitivity, convenient detection process, etc. Tris(2,2'-bipyridine)ruthenium(II) ([Ru(bpy)3] 2+ ) has excellent electrochemical stability and high ECL efficiency. Since its ECL behavior was reported, it has been the most widely used luminescent body. However, only by increasing the concentration of ruthenium bipyridine to enhance the efficiency of its ECL luminescent body is very limited. Therefore, designing a luminescent body with higher luminescence efficiency using ruthenium bipyridine has received extensive attention.

[0004] In recent years, some methods for iodide ion detection in the field of nuclear safety have been reported, such as ion chromatography (IC), inductively coupled plasma emission spectrometry (ICP-OES), X-ray fluorescence spectrometry, etc. However, these methods are still limited by problems such as high cost, long detection time, and low sensitivity in actual water source detection. And the method we are involved in has greatly improved these problems. By enhancing the luminescence efficiency of polymer dots, the sensitivity is improved. By utilizing the advantage of fast detection speed of electrochemiluminescence, the detection time is greatly saved. At the same time, the instruments used in the experiment are simple, the detection cost is extremely low, and only simple pretreatment is required for detection. Summary of the Invention

[0005] In order to solve the deficiencies of the above-mentioned technologies, the present invention provides a doped polymer dot, a preparation method thereof and an application thereof, synthesizes a polymer dot with high luminescence intensity, self-enhanced and doped, and realizes high-throughput, visual, fast and accurate detection of iodide ions through a self-made ECL imaging array in combination with electrochemiluminescence imaging technology.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A preparation method of doped polymer dots, using a derivative of hydrophobic ruthenium bipyridine as a doped dye and polymer dots with a co-reagent as an encapsulation body, and preparing the doped polymer dots Ru@Pdots by the method of nanoprecipitation.

[0007] Preferably, the method comprises the following steps:

[0008] Step S1, Synthesis of N-PFO: First, dissolve M1, M2, Pd(PPH3)4, and K2CO3 in Solution 1 for reaction to obtain a polymer solid M3, and then dissolve M3, diethylamine, and K2CO3 in Solution 2 for reaction to obtain a polymer solid N-PFO;

[0009] Step S2, Synthesis of Ru(bpy)3[B(C6F5)4]2: Under the condition of continuous stirring at room temperature, gradually dropwise mix the aqueous solutions of Ru(bpy)3Cl2·6H2O and Li[B(C6F5)4]2·nEt2O, centrifuge and wash the formed orange-red precipitate, and dry it overnight to obtain hydrophobic Ru(bpy)3[B(C6F5)4]2;

[0010] Step S3, Preparation of Ru@Pdots: Prepare the synthesized polymer N-PFO, Ru(bpy)3[B(C6F5)4]2, and poly(styrene-maleic anhydride) into tetrahydrofuran solutions respectively and mix them evenly with tetrahydrofuran. After ultrasonic degassing and oscillating ultrasonic treatment of the mixed solution, remove the tetrahydrofuran in the solution and concentrate the solution to obtain a Ru@Pdots dispersion.

[0011] Preferably, the specific process of Step S1 is as follows: Weigh a certain amount of M1, M2, Pd(PPH3)4, and K2CO3 respectively, dissolve them in Solution 1 which is a mixture of toluene and water, then place the mixed solution in a Schlenk tube, and under an argon atmosphere, stir and react at 90 - 110 °C for 2 - 4 days. Subsequently, purify the product to obtain a light orange polymer solid, which is M3;

[0012] Dissolve a certain amount of M3, diethylamine, and K2CO3 in Solution 2 which is a mixture of tetrahydrofuran and N,N-dimethylformamide. In a Schlenk tube under an argon atmosphere, keep stirring and reacting at 90 - 110 °C for 3 - 5 days. Perform two precipitations on the final solid product and purify it to obtain an orange polymer solid, which is the final product N-PFO.

[0013] Preferably, in step S1: M1 is 2,2'-(9,9-bis(6-bromohexyl)-9H-fluoren-2,7-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane), M2 is 2,7-dibromo-9,9-bis(6-bromohexyl)-9H-fluorene, and M3 is poly-9,9-bis(6-bromohexyl)-9H-fluorene.

[0014] Preferably, in step S1: the mass ratio of M1, M2, Pd(PPH3)4, and K2CO3 is 10:10:1:100, the mass ratio of M3, diethylamine, and K2CO3 is 1:10:10, and the volume ratio of solution one to solution two is 4:1.

[0015] Preferably, the specific process of step S3 is as follows: The synthesized polymer N-PFO, Ru(bpy)3[B(C6F5)4]2, and poly(styrene-maleic anhydride) are respectively configured into tetrahydrofuran solutions with the same concentration. A certain amount of each of the above three solutions is taken and mixed with tetrahydrofuran. After the mixed solution is ultrasonically degassed for 4 - 6 minutes, it is quickly injected into 85 - 95 mL of water. After shaking and mixing evenly, it is ultrasonically treated for 2 - 4 minutes. The tetrahydrofuran in the solution is removed using a rotary evaporator and the solution is concentrated to finally obtain a Ru@Pdots dispersion.

[0016] Preferably, in step S3, the three solutions are mixed with tetrahydrofuran according to a volume ratio of 2:4:1.

[0017] A doped polymer dot obtained by the above preparation method.

[0018] An application of a doped polymer dot, using the doped polymer dot as an ECL emitter to perform high-throughput imaging detection of iodide ions under the condition of no externally added coreactant.

[0019] Preferably, the polymer dots are mixed with a solution containing iodide ions and placed in an ECL imaging array. An ECL signal can be obtained by applying a potential to achieve the detection of iodide ions.

[0020] In the present invention, self-enhanced polymer dots - Ru@Pdots are synthesized by introducing intramolecular electron transfer and intermolecular resonance energy transfer processes. Ru@Pdots are used as self-enhanced ECL probes to fabricate an ECL imaging array capable of visual detection. The iodine in the detected solution is oxidized and consumes the nitrogen free radicals on the side chain of Ru@Pdots, thereby quenching the ECL of Ru@Pdots. This method not only realizes the visual detection of iodine content in natural seawater, but also provides ideas and possibilities for detecting radioactive substances in nuclear pollution.

[0021] The object of the present invention is to provide a high-throughput, visual, rapid and accurate method for detecting iodide ions. Compared with the prior art, the present invention uses doped polymer dots with high luminous efficiency as the ECL luminescent body, greatly improving the detection efficiency and detection sensitivity. Moreover, this method is simple to process and has good radiation resistance, and is expected to provide new ideas for detecting radioactive iodine substances in the ocean. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the preparation schematic diagram of the present invention: (A) Schematic diagram of the preparation of Ru@Pdots; (B) ECL imaging mechanism diagram between Ru@Pdots and I-.

[0023] Figure 2 It is the synthesis route diagram of N-PFO of the present invention.

[0024] Figure 3 It is the synthesis route diagram of Ru(bpy)3[B(C6F5)4]2 of the present invention.

[0025] Figure 4 It is the characterization diagram of Ru@Pdots prepared in the embodiment of the present invention: (A) TEM image of Ru@Pdots; (B) High-resolution TEM image of a single Ru@Pdots; (C) High-angle annular dark field image of Ru@Pdots and (D) C, (E) N, (F) O, (G) B, (H) Ru, (I) F element mapping diagrams.

[0026] Figure 5 It is the UV-visible absorption spectra diagram of N-PFO Pdots, Ru@Pdots, Ru(bpy)3[B(C6F5)4]2 prepared in the embodiment of the present invention.

[0027] Figure 6 It is the curve diagram of the product prepared in the embodiment of the present invention for detecting iodide ions: (A) ECL curve of I - concentration from 0.04 to 8000 μM, (B) calibration curve; (C) ECL image of I- concentration from 0.0008 to 4 μM, (D) calibration curve, n = 3.

[0028] Figure 7 It is the anti-interference performance evaluation diagram of the electrode modified with polymer dots in the embodiment of the present invention.

[0029] Figure 8 It is the comparison diagram of ECL intensity between the radiation environment and the non-radiation environment in the embodiment of the present invention.

[0030] Figure 9 It is the comparison of the detection results of iodide ions in seawater samples and the ECL imaging diagram between the embodiment of the present invention and the commercial kit. DETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] To solve the drawback of low detection sensitivity, the present invention doped two luminescent materials together in an appropriate proportion to synthesize a polymer dot with high luminous efficiency, greatly improving the detection efficiency. In addition, the electrochemical luminescence method is used in the preparation process. Electrochemical luminescence combines electrochemistry and chemiluminescence, and has advantages such as low background, high sensitivity, strong controllability, fast analysis speed, and wide linear range. By combining electrochemical luminescence with bioimaging technology, a visual detection of iodine is carried out. With the preparation of a self-made indium tin oxide porous electrode array, high-throughput detection of iodine is achieved. In addition, the radiation resistance of the luminescent material in the present invention is detected. The experimental results show that the material has good radiation resistance and has certain application value in the fields of marine environmental monitoring, nuclear safety, cancer radiotherapy, etc.

[0033] In the present invention, a co-reactant-carrying N-PFO Pdots is obtained by introducing a tertiary amine into the side chain of a commercial polymer: poly(9,9-dioctylfluorene-2,7-diyl) (PFO). A large number of derivative molecules of ruthenium bipyridine (Ru(bpy)3[B(C6F5)4]2) are encapsulated in the N-PFO Pdots as carriers. Through the resonance energy transfer mechanism between the hydrophobic ruthenium derivative and the N-PFO molecule, the ECL emission of ruthenium is greatly enhanced. The synthesized Ru@Pdots can exhibit excellent ECL performance in PBS without the need to additionally add a co-reactant. Note: Here, PBS refers to a phosphate buffer solution with a pH of 7.4.

[0034] Using this self-enhanced ECL probe and ECL imaging for the visual detection of I - Specifically, the Ru@Pdots modified on the electrode are first oxidized and deprotonated on the electrode. Then, iodide ions in the solution are oxidized to iodide radical ions on the electrode surface, and the iodide radical ions can quench the ECL of Ru@Pdots (i.e., weaken the ECL signal). The more iodine content in the solution, the weaker the ECL signal, and the brightness of the ECL imaging will also gradually decrease.

[0035] The detection principle is as follows: First, Ru@Pdots are modified on the electrode surface. The Ru@Pdots are oxidized and deprotonated on the electrode, and the generated nitrogen radicals are consumed by the iodide radical ions formed by the oxidation in the solution, resulting in the quenching of ECL. The concentration of iodide ions is detected by quenching ECL with iodide radical ions.

[0036] This detection method has a wide detection range and high sensitivity, realizing the visual detection of iodine content in seawater samples. In addition, after the probe is irradiated, its ECL intensity remains unchanged, demonstrating the potential application value of the proposed method in the fields of marine environmental monitoring, nuclear radiation pollution, and biological health.

[0037] Example:

[0038] Preparation of doped polymer dots Ru@Pdots is as Figure 1 shown:

[0039] Synthesis of N-PFO: As Figure 2 shown, first, take 111.6 mg of M1, 97.5 mg of M2, 17.3 mg of Pd(PPH3)4, and 207.3 mg of K2CO3 respectively, dissolve them in a mixed solution of 4 mL of toluene and 1 mL of H2O, then place the solution in a Schlenk tube, and stir and react at 100 °C for 3 days under an argon atmosphere. Subsequently, the product is purified twice with methanol (add sufficient cold methanol and stir gently until the polymer is completely precipitated, discard the supernatant, and then dry the precipitate in an oven at 98 °C), and finally, a light orange polymer solid, namely M3, is obtained. Subsequently, 0.16 mM of M3, 16 mM of diethylamine, and 221.1 mg of K2CO3 are dissolved in a mixed solution of 16 mL of tetrahydrofuran (THF) and 4 mL of N,N-dimethylformamide (DMF), and stirred and reacted at 100 °C for 4 days in a Schlenk tube under an argon atmosphere. Finally, the final solid product is precipitated twice with methanol (add sufficient cold methanol and stir gently until the polymer is completely precipitated, discard the supernatant), and the orange polymer solid, namely the final product N-PFO, is obtained through purification.

[0040] Among them, M1 is 2,2'-(9,9-bis(6-bromohexyl)-9H-fluoren-2,7-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane), M2 is 2,7-dibromo-9,9-bis(6-bromohexyl)-9H-fluorene, and M3 is poly-9,9-bis(6-bromohexyl)-9H-fluorene.

[0041] Synthesis of Ru(bpy)3[B(C6F5)4]2: As Figure 3As shown, an aqueous solution of Ru(bpy)3Cl2·6H2O (74.9 mg, 0.1 mmol) and Li[B(C6F5)4]2·nEt2O (217.2 mg, 0.1 mmol) was added dropwise under continuous stirring at room temperature. The formed orange-red precipitate was centrifuged and washed (centrifuged at 10000 r for 10 minutes and washed with triple-distilled water), and the finally obtained precipitate was dried overnight at 80 °C to obtain hydrophobic Ru(bpy)3[B(C6F5)4]2.

[0042] Preparation of Ru@Pdots: The synthesized polymer N-PFO, Ru(bpy)3[B(C6F5)4]2, and poly(styrene-maleic anhydride) (PSMA) were respectively prepared into tetrahydrofuran solutions of 10 mg mL -1 . Taking a 15 mL centrifuge tube, 100 μL of 10 mg mL -1 N-PFO solution, 200 μL of 10 mg mL -1 Ru(bpy)3Cl2·6H2O solution, 50 μL of 10 mg mL -1 PSMA solution and 9.65 mL of tetrahydrofuran were added and mixed evenly. After the mixed solution was degassed by ultrasonic treatment for 5 minutes, it was quickly injected into 90 mL of water, and after shaking and mixing evenly, it was ultrasonicated for 3 minutes. Finally, the tetrahydrofuran in the solution was removed using a rotary evaporator and the solution was concentrated to finally obtain a Ru@Pdots dispersion with a concentration of 50 μg mL - 1 .

[0043] Characterization of Ru@Pdots is as Figure 4 shown:

[0044] The polymer dots Ru@Pdots were finally synthesized using the nanoprecipitation method. From the transmission electron microscope (TEM) ( Figure 4 A-B) and its high-angle annular dark-field image ( Figure 4 C), it can be seen that Ru@Pdots are spherical particles with a diameter of about 100 nm. The high-angle annular dark-field (HAADF) image ( Figure 4 C) and energy-dispersive X-ray spectroscopy (EDS) ( Figure 4 D-I) show clear distributions of elements C ( Figure 4 D), N ( Figure 4 E), O ( Figure 4 F), B ( Figure 4 G), Ru ( Figure 4 H), and F ( Figure 4 I), further confirming the effective doping of Ru(bpy)3[B(C6F5)4]2 in Ru@Pdots.

[0045] After doping N-PFO with Ru(bpy)3[B(C6F5)4]2, ultraviolet-visible spectroscopy analysis was performed on the synthesized Ru@Pdots (as Figure 5 shown). The synthesized Ru@Pdots had two obvious absorption peaks at 289 nm and 39 nm. Among them, the absorption peak at 289 nm can be attributed to the fusion of the absorption peak of N-PFO Pdots at 281 nm and the absorption peak of Ru(bpy)3[B(C6F5)4]2 at 298 nm. And its absorption peak at 391 nm originated from the fusion of the absorption peak of N-PFO Pdots at 387 nm and the absorption peak of Ru(bpy)3[B(C6F5)4]2 at 451 nm, which also proved the successful doping of the two materials.

[0046] The prepared Ru@Pdots were applied to the detection of iodide ions:

[0047] For the detection of ECL, a platinum wire electrode was used as the counter electrode, a silver / silver chloride electrode was used as the reference electrode, and the luminophore was modified on the glassy carbon electrode (working electrode). Potassium iodide with different concentrations was dissolved in 0.1 M, pH 7.4 PBS, and the ECL intensity was directly detected through the ECL analysis system. Different from the ECL detection, the ECL imaging was performed with an indium tin oxide (ITO) glass electrode as the working electrode. A porous sticker was pasted on the ITO electrode to make an ECL electrode array, and then Ru@Pdots were modified in the array holes. A silver / silver chloride wire was used as the reference electrode and a platinum wire was used as the counter electrode, and the image was taken using a self-made imaging system (camera: Chongqing Aopu UOP0600CSC, lens: Canon 50, EF1.2).

[0048] Under the optimized preparation conditions, Ru@Pdots were used as the detection probe for the subsequent detection of iodide ions. As Figure 6 shown, for each concentration point, three parallel experiments were carried out, and finally the average value of the three values was taken for plotting. The synthesized Ru@Pdots were first modified on the glassy carbon electrode for the ECL detection of iodide ions. As the amount of iodide ions added to the system increased, the ECL intensity of Ru@Pdots gradually decreased ( Figure 6 A). This is because during the electrochemical oxidation process, iodide ions were oxidized into iodine radicals, consuming the radicals generated by the tertiary amines on the N-PFO side chain, thus quenching the ECL signal. In the range of 0.04 μM - 8000 μM, the ECL intensity showed a good linear relationship with the logarithm of the iodide ion concentration, and the detection limit (LOD) was 5 nM ( Figure 6 B). Based on the high ECL signal intensity of Ru@Pdots, its application in the ECL imaging detection of iodide ions was further explored. It was found that the imaging brightness of Ru@Pdots in the ECL imaging array also gradually decreased with the increase of iodide ion concentration (Figure 6 C), and in the range of 0.0008 μM - 4 μM, the ECL imaging intensity shows a good linear relationship with the logarithm of the iodide ion concentration, and the LOD is 0.1 nM ( Figure 6 D). The above results indicate that the application of Ru@Pdots in iodide ion detection not only shows a wide detection range and high sensitivity, but also shows a lower detection limit in high-throughput ECL imaging detection, which is of great significance for the development of high-throughput visual monitoring of iodide ions.

[0049] To explore the specificity of the ECL sensor, Ru@Pdots was compared in a PBS blank solution ( Figure 7 a), a mixed solution containing 0.08 mM of interfering ions (Cl - , Br - , NO3 - , SO4 2- , CO3 2- , HCO3 - , H2PO4 - and HPO4 2- ) ( Figure 7 b), a 0.08 mM iodide ion solution ( Figure 7 c), and a solution of 0.08 mM iodide ion plus interfering ions ( Figure 7 d) for the difference in ECL intensity. As Figure 7 shown, the intensity of Ru@Pdots in the solution with interfering ions ( Figure 7 b) is basically the same as that in the blank solution ( Figure 7 a), but there is an obvious ECL quenching effect in the solution containing 0.08 mM I - ( Figure 7 c) and the mixed solution of 0.08 mM I - ( Figure 7 d) with other interfering ions added, and the intensities of the two are almost the same. The above results show that the ECL sensor has high specificity for iodide ion detection, providing the possibility for the rapid and accurate detection of iodine in complex matrices in the environment.

[0050] In addition, Ru@Pdots was modified on a polished and cleaned glassy carbon electrode, and the electrode was divided into two groups. One group was placed in a glass container (0.7 L) containing 0.3 MBq I-131 for radiation treatment as the experimental group. At the same time, the other group was placed in a glass container without I-131 as the control group. After the two groups of electrodes were left standing at room temperature for 5 minutes, the ECL signals of the two groups of modified electrodes were detected respectively in PBS with a concentration of 0.1 M and pH 7.4. As Figure 8As shown, the ECL intensities of Pdots (with) treated with a radioactive environment and Pdots (without) not treated with a radioactive environment in PBS were compared. It can be seen that there is almost no difference in the ECL between the two, indicating that the ECL intensity of the Ru@Pdots of the present invention is not interfered by the radioactive environment, demonstrating the significance of this method for radioactive environment monitoring.

[0051] On this basis, the iodine ion contents of offshore seawater at three locations (marked locations) were analyzed respectively, and the detection results were compared with those of a commercial kit (as Figure 9 shown). The seawater samples at the three locations were respectively marked as 1, 2, and 3, and the method proposed in the present invention was used to detect them. It can be seen from the bar chart that the proposed method (ECL) is consistent with the detection results obtained using the kit (Kit). In addition, ITO imaging arrays were also used to perform ECL imaging detection on them, and the results showed that the method of the present invention has high accuracy, and the ECL luminophore, that is, the doped polymer dots (Ru@Pdots) synthesized in the present invention, has the potential for quantitative detection of iodine ions in actual seawater samples.

[0052] In the synthesis of the luminescent material of the present invention, the processes of intramolecular electron transfer and intermolecular resonance energy transfer are introduced, greatly enhancing the luminescence efficiency of the luminophore. Using the method of electrochemiluminescence imaging, combining the advantages of electrochemistry, chemiluminescence, and bioimaging, it exhibits a wide detection range and high sensitivity, and at the same time, high-throughput and visual detection can be carried out. The detection of the present invention has high accuracy, and after anti-radiation testing, it is proved that this method is not affected by the radiation environment, providing the possibility for monitoring iodine in the radioactive environment.

[0053] The above embodiments are not limitations on the present invention, and the present invention is not limited to the above examples either. Changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the technical solution of the present invention also fall within the protection scope of the present invention.

Claims

1. A method for preparing doped polymer dots, characterized in that: Using hydrophobic bipyridine ruthenium derivatives as doping dyes and polymer dots with co-reactants as inclusions, doped polymer dots Ru@Pdots were prepared by nanoprecipitation. The method comprises the following steps: Step S1, synthesis of N-PFO: firstly, M1, M2, Pd(PPH3)4, and K2CO3 are dissolved in solution 1 to react to obtain a polymer solid M3, and then M3, diethylamine, and K2CO3 are dissolved in solution 2 to react to obtain a polymer solid N-PFO; Weigh a certain amount of M1, M2, Pd(PPH3)4, and K2CO3 respectively, dissolve them in a solution of toluene and water, then place the mixed solution in a Schlenk tube, and stir the reaction at 90-110°C for 2-4 days under an argon atmosphere, then purify the product to obtain a light orange polymer solid, namely M3; A certain amount of M3, diethylamine, and K2CO3 were dissolved in a solution 2 mixed with tetrahydrofuran and N,N-dimethylformamide, and stirred at 90-110°C in a Schlenk tube under an argon atmosphere for 3-5 days. The final solid product was precipitated twice and purified to obtain an orange polymer solid, which was the final product N-PFO; Wherein, M1 is 2,2'-(9,9-bis(6-bromohexyl)-9H-fluorene-2,7-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane), M2 is 2,7-dibromo-9,9-bis(6-bromohexyl)-9H-fluorene, and M3 is poly-9,9-bis(6-bromohexyl)-9H-fluorene; Step S2, synthesis of Ru(bpy)3[B(C6F5)4]2: mixing Ru(bpy)3Cl2·6H2O and Li[B(C6F5)4]2·nEt2O aqueous solutions dropwise under continuous stirring at room temperature, centrifuging the formed orange-red precipitate, washing, and drying overnight to obtain hydrophobic Ru(bpy)3[B(C6F5)4]2; Step S3, preparation of Ru@Pdots: The synthesized polymer N-PFO, Ru(bpy)3[B(C6F5)4]2 and poly(styrene-maleic anhydride) are respectively prepared into tetrahydrofuran solutions and mixed evenly with tetrahydrofuran. The mixed solution is subjected to ultrasonic degassing and oscillation ultrasonic treatment, and the tetrahydrofuran in the solution is removed and the solution is concentrated to obtain a Ru@Pdots dispersion.

2. The method for preparing doped polymer dots according to claim 1, wherein: In the step S1: the mass ratio of M1, M2, Pd(PPH3)4, and K2CO2 is 10:10:1:100, the mass ratio of M3, diethylamine, and K2CO3 is 1:10:10, and the volume ratio of solution 1 and solution 2 is 4:

1.

3. The method for preparing doped polymer dots according to claim 1, wherein: The specific process of step S3 is as follows: the synthesized polymers N-PFO, Ru(bpy)3[B(C6F5)4]2 and poly(styrene-maleic anhydride) are respectively configured into tetrahydrofuran solutions with the same concentration, a certain amount of the above three solutions are respectively mixed with tetrahydrofuran, the mixed solution is ultrasonically degassed for 4-6 minutes, and then quickly injected into 85-95mL of water, after oscillation and mixing, ultrasonicated for 2-4 minutes, and the tetrahydrofuran in the solution is removed by a rotary evaporator and the solution is concentrated to finally obtain a Ru@Pdots dispersion.

4. The method for preparing doped polymer dots according to claim 3, wherein: In step S3, the three solutions are mixed with tetrahydrofuran in a volume ratio of 2:4:

1.

5. A doped polymer dot obtained by the preparation method of claim 1.

6. A use of the doped polymer dots as claimed in claim 5, characterized in that: Using doped polymer dots as ECL luminophores, high-throughput imaging detection of iodide ions was performed without the addition of co-reactants.

7. The use of the doped polymer dots according to claim 6, characterized in that: The polymer dots are mixed with a solution containing iodide ions and placed in an ECL imaging array. By applying a potential, an ECL signal can be obtained to detect iodide ions.

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