A paper-based cadmium ion-imprinted fluorescence sensor integrating AIE probe and ion-imprinted polymer and detection method thereof

Abstract

The invention discloses a paper-based cadmium ion imprinted fluorescence sensor integrating an AIE probe and an ion imprinted polymer and a detection method thereof. In the invention, MPTES is used as a functional monomer, cadmium ions are used as an ion template, and TEOS is used as a crosslinking agent, and a Cd@IIP paper-based imprinted material is prepared by using a sol-gel technology. The Cd@IIP paper-based imprinted material can selectively enrich cadmium ions and has good adsorption capacity. The invention also introduces a fluorescence probe (PBQ) with a metal coordination-induced AIE effect for specific recognition and fluorescence detection of cadmium ions. Under the synergistic action of biomimetic recognition and the AIE effect, the novel paper-based cadmium ion imprinted fluorescence sensor based on the Cd@IIP paper-based imprinted material and the PBQ fluorescence probe has a dual recognition ability and can rapidly detect trace cadmium ions in complex samples by fluorescence colorimetry.

Description

Technical Field

[0001] The present invention relates to the technical field of food safety detection, and particularly relates to a paper-based cadmium ion imprinted fluorescence sensor integrating an AIE probe and an ion imprinted polymer and a detection method thereof. Background Art

[0002] Cadmium is a common toxic heavy metal pollutant. Human activities such as mining, metallurgy, electroplating, etc. will all discharge cadmium-containing wastewater. The cadmium concentration in cadmium-containing wastewater far exceeds the natural sources of cadmium. When these cadmium-containing wastewaters are discharged into the environment, they will pollute the water body. Cadmium has the property of bioaccumulation and can accumulate in water, aquatic organisms, animals and plants through the food chain, and finally enter the human body through ingestion. Moreover, cadmium can be absorbed in the human body and accumulate in the body. Long-term exposure to a cadmium-containing environment will affect the main organs of the human body, leading to various diseases such as osteomalacia, kidney failure, and nervous system defects. Therefore, simple, rapid, and accurate detection of cadmium ions in food is of great significance for ensuring food safety and people's health.

[0003] Traditional analytical detection methods for cadmium ions mainly include: atomic absorption spectrometry, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry, anodic stripping voltammetry, etc. However, these detection methods require expensive instruments, the detection personnel need to master certain professional skills, and the required pretreatment procedures for detection are relatively cumbersome and time-consuming. In grass-roots detection work where the detection conditions are relatively limited, there is an even greater need for a rapid, simple, accurate, and sensitive analytical detection method for cadmium ions.

[0004] Paper-based fluorescence sensors based on organic fluorescence probes have the advantages of convenient synthesis, simple operation, less sample consumption, low production cost, good biocompatibility, and short detection time, and have been applied in the field of rapid analysis of cadmium ions. Among them, fluorescence probes with aggregation-induced emission (AIE) properties can significantly improve the luminescence performance in the aggregated state or solid state, and can improve the fluorescence analysis performance of paper-based sensors on solid interfaces. However, due to the lack of the enrichment function for cadmium ions in current paper-based sensors based on AIE probes, the detection efficiency and analysis performance of such paper-based sensors for trace target substances in complex samples are poor. Therefore, how to improve the detection efficiency and analysis performance of paper-based sensors based on AIE probes for trace target substances in complex samples is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0005] In view of this, the present invention provides a paper-based cadmium ion-imprinted fluorescence sensor integrating an AIE probe and an ion-imprinted polymer, as well as a detection method. The novel paper-based cadmium ion-imprinted fluorescence sensor prepared by combining the selective recognition and high luminescence performance of the AIE fluorescence probe with the selective enrichment performance of the ion-imprinted polymer (IIP) has dual recognition capabilities and can rapidly and efficiently enrich and detect trace cadmium ions in complex samples through fluorescence colorimetry.

[0006] In order to achieve the above effects, the present invention adopts the following technical solutions:

[0007] A paper-based cadmium ion-imprinted fluorescence sensor integrating an AIE probe and an ion-imprinted polymer, comprising a Cd@IIP paper-based imprinted material and an AIE probe solution.

[0008] Furthermore, the preparation method of the Cd@IIP paper-based imprinted material comprises the following steps:

[0009] (1) Cleaning and modifying the blank paper-based FP to obtain a modified paper-based material;

[0010] (2) Constructing a cadmium ion-imprinted layer on the surface of the pretreated paper-based material through a functional monomer, a template ion, and a cross-linking agent to obtain a Cd@IIP(Cd) paper-based imprinted material;

[0011] (3) Eluting the template from the constructed cadmium ion-imprinted layer to obtain the Cd@IIP paper-based imprinted material.

[0012] Furthermore, the cleaning of the blank paper-based FP in step (1) is carried out by soaking in hydrochloric acid to fully clean and activate the surface groups of the paper-based material. During this cleaning process, functional groups such as hydroxyl groups on the paper-based surface are fully activated, providing original sites for subsequent reactions.

[0013] Furthermore, the modifying solution used in step (1) is an anionic polyelectrolyte solution.

[0014] Furthermore, the anionic polyelectrolyte solution includes a polyacrylic acid solution (PAA) or sodium polystyrene sulfonate (PSS) with a concentration of 0.1%-2%; the blank paper-based material is Whatman filter paper, and the blank paper-based material can enable the solution to quickly pass through to the enrichment area, constructing a novel paper-based cadmium ion-imprinted fluorescence sensor.

[0015] Furthermore, the functional monomer in step (2) is 3-mercaptopropyltriethoxysilane (MPTES), the molar ratio of the functional monomer to the template ion is 0.1:10 - 0.1:20, the cross-linking agent is tetraethyl orthosilicate (TEOS), and the molar ratio of the cross-linking agent to the template ion is 0.1:10 - 0.1:20.

[0016] Further, when eluting the template from the constructed cadmium ion imprinted layer in step (3), the template eluent used is EDTA, nitric acid, or a combination of both, and water is used to remove the residual elution solution. The concentration of the EDTA is 0.1 mol / L - 10 mol / L, and the concentration of the nitric acid is 0.1 mol / L - 5 mol / L. EDTA and nitric acid can effectively remove cadmium ions in the cadmium ion imprinted layer, leaving pores with specific sizes of cadmium ions, so that cadmium ions can be specifically adsorbed in subsequent experiments.

[0017] Further, the template is cadmium nitrate, and the concentration is 0.01 mol / L - 0.05 mol / L.

[0018] Further, the preparation method of the Cd@IIP paper-based imprinted material includes the following steps:

[0019] 1) Prepare 20 mL of a hydrochloric acid solution with a concentration of 0.2 mol / L, soak the blank paper-based FP in the hydrochloric acid solution for cleaning, take it out, wash it with ultrapure water until neutral, and dry it to obtain the cleaned paper-based material;

[0020] 2) Immerse the cleaned paper-based material in the anionic polyelectrolyte solution, after ultrasonic treatment for 30 min, take it out, wash it with ultrapure water, and dry it to obtain the modified paper-based material;

[0021] 3) Prepare a cadmium nitrate solution with a concentration of 0.01 mol / L - 0.05 mol / L, and the solvent is an ethanol aqueous solution (ethanol: water = 6:4 - 1:1, v / v). Add a reaction catalyst and a functional monomer (MPTES) to the cadmium nitrate solution, mix well, and carry out pre-polymerization at 60 °C. The pre-polymerization time is 1 - 5 h;

[0022] 4) After the pre-polymerization is completed, add a cross-linking agent (TEOS) to the pre-polymerization solution, after ultrasonic treatment for 30 min, add the modified paper-based material, and carry out the formal polymerization reaction at 60 °C;

[0023] 5) After the formal polymerization is completed, take it out, wash it with ethanol and ultrapure water respectively to obtain the Cd@IIP(Cd) paper-based imprinted material; use the template eluent to elute the template; wash it with ultrapure water until neutral, and dry it to obtain the Cd@IIP paper-based imprinted material.

[0024] The reaction catalyst in step 3) is acetic acid or ammonia water, and the molar ratio of the reaction catalyst to the template ion is 0.01 - 10 - 0.1:10.

[0025] The present invention constructs a cadmium ion imprinted layer on the surface of a paper substrate by using the sol-gel method. A cadmium ion imprinted layer is constructed on the surface of the paper substrate through a functional monomer and a cross-linking agent. The cadmium ion template is eluted and dried to obtain a Cd@IIP paper-based imprinted material with specific sites.

[0026] Further, under acidic conditions, MPTES undergoes a hydrolysis reaction in an ethanol medium.

[0027] Further, the AIE probe is prepared by a condensation reaction of potassium carbonate, 2,6-bis(chloromethyl)pyridine, potassium iodide, and 8-hydroxyquinoline.

[0028] Further, the molar ratio of potassium carbonate, 2,6-bis(chloromethyl)pyridine, potassium iodide, and 8-hydroxyquinoline is 0.1 - 10:0.1 - 10:0.01 - 2:0.1 - 10.

[0029] Further, the temperature of the condensation reaction is 50 - 75 °C, the time is 4 - 20 h, the condensation reaction is carried out in an organic solvent, and the organic solvent includes acetone.

[0030] Further, the concentration of the AIE probe solution is 10 μmol / L - 200 μmol / L.

[0031] The present invention also provides a detection method for the paper-based cadmium ion imprinted fluorescence sensor integrating the AIE probe and the ion imprinted polymer, including the following steps:

[0032] (1) A nitrocellulose membrane is set at the front end of the support, the Cd@IIP paper-based imprinted material is set in the middle, and a water absorbent pad is set at the rear end to obtain a paper-based sensor;

[0033] (2) The front end of the paper-based sensor is placed in a test sample containing cadmium ions for sample loading;

[0034] (3) After the sample loading is completed, the Cd@IIP paper-based imprinted material is removed, washed with ultrapure water, and dried to obtain the dried Cd@IIP paper-based imprinted material;

[0035] (4) An AIE probe solution is dropped on the dried Cd@IIP paper-based imprinted material for reaction, and quantitative analysis is carried out by fluorescence colorimetry.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) In this invention, MPTES is used as the functional monomer, cadmium ions as the ionic template, and TEOS as the crosslinking agent. The Cd@IIP paper-based imprinted material is prepared by the sol-gel technique. The Cd@IIP paper-based imprinted material can selectively enrich cadmium ions and has good adsorption capacity. Meanwhile, a cadmium ion fluorescent probe (2,6-bis(quinolin-8-yloxy)methyl)pyridine, PBQ), which has a metal coordination-induced AIE effect, is introduced for the specific recognition and fluorescence detection of cadmium ions. Under the synergistic effect of biomimetic recognition and AIE effect, the novel paper-based cadmium ion imprinted fluorescence sensor based on the Cd@IIP paper-based imprinted material and the PBQ fluorescent probe has dual recognition ability and can rapidly detect trace cadmium ions in complex samples by fluorescence colorimetry.

[0038] (2) The Cd@IIP paper-based imprinted material prepared in this invention not only has the functions of selective adsorption and enrichment of ion imprinting, but also has the advantage of low cost of the paper-based platform. The maximum adsorption capacity of the Cd@IIP paper-based imprinted material can reach 598.00 mg g -1 . The adsorption process of the Cd@IIP paper-based imprinted material is monolayer adsorption on the material surface, and it has abundant specific recognition sites and higher binding ability to cadmium ions, so it has strong adsorption capacity.

[0039] (3) This invention proposes a paper-based cadmium ion imprinted fluorescence sensor integrating an AIE probe and an ion imprinted material, as well as a complete set of methods for rapidly detecting cadmium ions in food, which has advantages such as plug-and-play and simple operation, and can complete the analysis of cadmium ions in the sample extract within 30 minutes. Description of the Drawings

[0040] Figure 1 is the preparation flow chart of the Cd@IIP paper-based imprinted material of this invention and the schematic diagram of the detection method of the ion imprinted fluorescence sensor.

[0041] Figure 2 is the transmission electron microscope image of the microstructure of the blank paper-based FP and the Cd@IIP paper-based imprinted material of this invention.

[0042] Figure 3 is the X-ray photoelectron spectroscopy image of the polyacrylic acid-modified paper-based material FP@PAA and the Cd@IIP paper-based imprinted material of this invention.

[0043] Figure 4 is the selective adsorption diagram of cadmium ions by the Cd@IIP paper-based imprinted material of this invention.

[0044] Figure 5 is the nuclear magnetic resonance hydrogen spectrum image of the AIE probe of this invention.

[0045] Figure 6It is the fluorescence response diagram of the AIE probe of the present invention for selectively recognizing cadmium ions.

[0046] Figure 7 It is the fluorescence quantitative analysis diagram of the paper-based cadmium ion imprinted fluorescence sensor of the present invention for different concentrations of cadmium ions.

[0047] Figure 8 It is the schematic diagram of the fluorescence response of the paper-based cadmium ion imprinted fluorescence sensor of the present invention for different concentrations of cadmium ions.

[0048] Figure 9 It is the RGB analysis result of the fluorescence response of the paper-based cadmium ion imprinted fluorescence sensor of the present invention for different concentrations of cadmium ions. Specific implementation manners

[0049] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope protected by the present invention.

[0050] In the following embodiments, the test methods or testing methods are all conventional methods unless otherwise specified; the raw materials and auxiliaries are all obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.

[0051] Example 1: Preparation and characterization of Cd@IIP paper-based imprinted material

[0052] The preparation method of the Cd@IIP paper-based imprinted material is specifically as follows:

[0053] 1) Prepare 20 mL of hydrochloric acid solution with a concentration of 0.2 mol / L, soak the blank paper-based FP in the hydrochloric acid solution for cleaning, take it out and wash it with ultrapure water until neutral, and dry it at 60 °C for 2 h to obtain the cleaned paper-based FP@OH;

[0054] 2) Immerse the cleaned paper-based material in a 0.5% polyacrylic acid (PAA) solution, ultrasonicate for 30 min, take it out and wash it with ultrapure water, and dry it at 60 °C for 2 h to obtain the polyacrylic acid-modified paper-based material FP@PAA;

[0055] 3) Prepare a cadmium nitrate solution (0.07 g, 0.23 mmol), with the solvent being an ethanol aqueous solution (ethanol: water = 6:4, v / v). Add acetic acid and a functional monomer (MPTES) to the cadmium nitrate solution. The usage amount of acetic acid is 1.8 μmol, and the usage amount of the functional monomer is 3 mmol. After mixing evenly, carry out prepolymerization at 60 °C, and the prepolymerization time is 3 h;

[0056] 4) After the pre-polymerization is completed, a cross-linking agent (TEOS) is added to the pre-polymerization solution. The dosage of the cross-linking agent is 2.5 mmol. After ultrasonic treatment for 30 min, a paper-based material FP@PAA modified with polyacrylic acid is added, and the formal polymerization reaction is carried out at 60 °C. The formal polymerization time is 18 h;

[0057] 5) After the formal polymerization is completed, it is taken out and washed with ethanol and ultrapure water respectively. The template eluent used for template elution of the constructed cadmium ion imprinted layer is EDTA and nitric acid, and the residual elution solution is removed with water. The concentration of EDTA is 0.1 mol / L, and the concentration of nitric acid is 0.2 mol / L. It is washed with ultrapure water and dried at 60 °C for 2 h to obtain the Cd@IIP paper-based imprinted material.

[0058] The prepared Cd@IIP paper-based imprinted material, blank paper-based FP, and paper-based material FP@PAA modified with polyacrylic acid are respectively subjected to transmission electron microscopy analysis and X-ray photoelectron spectroscopy analysis of the microstructure.

[0059] Figure 2 is the transmission electron microscopy image of the microstructure of the blank paper-based FP and the Cd@IIP paper-based imprinted material of the present invention. From Figure 2 it can be seen that there is no other substance attached to the blank paper-based FP, while there are a large number of microspheres loaded on the surface of the Cd@IIP paper-based imprinted material. It proves the successful modification of the ion imprinted polymer on the surface of the Cd@IIP paper-based imprinted material.

[0060] Figure 3 is the X-ray photoelectron spectroscopy image of the paper-based material FP@PAA modified with polyacrylic acid and the Cd@IIP paper-based imprinted material of the present invention. From Figure 3 it can be seen that the peaks with binding energies of 286 eV and 533 eV correspond to C1s and O1s respectively, which are the common peaks of both the paper-based material FP@PAA modified with polyacrylic acid and the Cd@IIP paper-based imprinted material; the peaks with binding energies of 162 eV and 103 eV are the new peaks of the Cd@IIP paper-based imprinted material, which are S2p and Si2p respectively. Their sources are sulfur and silicon elements introduced by constructing ion imprints by the sol-gel method, proving the successful construction of the silicon imprinted layer on the Cd@IIP paper-based imprinted material.

[0061] Figure 4 is the selective adsorption diagram of cadmium ions by the Cd@IIP paper-based imprinted material of the present invention. From Figure 4 it can be seen that it proves that the Cd@IIP paper-based imprinted material has good selective adsorption ability for cadmium ions.

[0062] Example 2: Preparation method and characterization of AIE probe

[0063] The preparation method of the AIE probe is as follows:

[0064] Potassium carbonate (415 mg, 3 mmol), 2,6-bis(chloromethyl)pyridine (175 mg, 1 mmol), potassium iodide (33 mg, 0.2 mmol) and 8-hydroxyquinoline (290 mg, 2 mmol) were added to a 50 mL round-bottom flask for condensation reaction. The condensation reaction was carried out in an organic solvent; the organic solvent could be acetone (20 mL). The temperature of the condensation reaction was 70 °C; the time was 6 h. After the reaction, it was cooled to room temperature, and acetone was removed by rotary evaporation to obtain a crude product. The crude product was separated and purified by column chromatography. The eluent used for column chromatography could be a mixed system of dichloromethane and methanol (dichloromethane: methanol = 30:1, v / v). After separation and purification, a white solid PBQ (305 mg, yield 78%) was obtained. A PBQ fluorescent probe solution was prepared, with the solvent being an acetone solution (20 mL), and the concentration of the solution was 20 μmol / L; the PBQ fluorescent probe solution could react with cadmium ions to form a purple fluorescent complex.

[0065] Figure 5 is the 1H NMR spectrum of the AIE probe of the present invention. From Figure 5 it can be seen that the number of hydrogen atoms in the spectrum is consistent with the theoretical hydrogen number in the probe molecule (both are 19), confirming the successful preparation of the AIE probe.

[0066] Figure 6 is the fluorescence response diagram of the selective recognition of cadmium ions by the AIE probe of the present invention. From Figure 6 it can be seen that compared with other metal ions, cadmium ions can significantly produce fluorescence when combined with the probe, proving that the AIE probe has good selective recognition ability for cadmium ions.

[0067] Example 3: Construction and detection method of a paper-based cadmium ion imprinted fluorescence sensor

[0068] Assemble a paper-based cadmium ion imprinted fluorescence sensor and use the paper-based cadmium ion imprinted fluorescence sensor to detect the cadmium content in the sample. The specific steps are as follows:

[0069] (1) Preparation of the paper-based cadmium ion imprinted fluorescence sensor:

[0070] A 2.5 cm * 0.6 cm nitrocellulose membrane (as the sample loading channel) was pasted at the front end on a 4.5 cm * 0.6 cm PVC backplane, and a water-absorbing pad was pasted at the back end to provide the sample loading driving force. Finally, a Cd@IIP paper-based imprinted material was pasted in the middle to obtain a paper-based cadmium ion imprinted fluorescence sensor integrating sample loading, enrichment and detection;

[0071] (2) Preparation of the sample loading solution:

[0072] Accurately weigh 1 g of the sample into a microwave digestion vessel, add 10 mL of nitric acid, cover it, and let it stand for 5 h, then carry out microwave digestion; the temperature of the microwave digestion is 180 °C, and the microwave digestion time is 5 h; after the microwave digestion is completed and cooled, take out the digestion vessel, and drive the acid to about 2 mL at 150 °C; after cooling again, transfer the digestion solution to a volumetric flask and make up the volume to 10 mL with water to obtain a sample extract. Take 1 mL of the sample extract and mix it with Tris-HCl buffer solution according to a volume ratio of 1:1. The pH of the Tris-HCl buffer solution is about 7, and the concentration of the Tris-HCl buffer solution is 0.05 mol / L. Filter it with a 0.45 μm filter membrane to obtain a sample loading solution;

[0073] (3) Detect the cadmium content in the loading solution:

[0074] Absorb 200 μL of the loading solution or a cadmium standard solution prepared with Tris-HCl buffer solution into the micro-wells of a 96-well microplate. Vertically insert the paper-based cadmium ion imprinted fluorescence sensor and carry out loading for 20 min; after the loading is completed, tear off the water-absorbing pad, wash the Cd@IIP paper-based imprinted material with ultrapure water, and dry it; drop 5 μL of PBQ fluorescence probe solution on the Cd@IIP paper-based imprinted material for reaction, and carry out quantitative analysis by fluorescence colorimetry.

[0075] Among them, the micro-wells of a 96-well microplate are used as micro-loading wells. The 96-well microplate is made of high-purity polypropylene and has the advantages of high chemical stability, space saving, large storage capacity, etc. It can be combined with a multi-channel pipette, a high-throughput automatic liquid handling instrument and software to realize high-throughput operation of samples. Specifically, choosing a detachable 96-well microplate can further save space and can operate multiple samples synchronously. At the same time, its micro-loading volume also saves the use of reagents and is more environmentally friendly. During specific operation, a fluorescence detection software or Photoshop can be used to detect the fluorescence response, and the fluorescence response value is linearly fitted with the cadmium ion concentration.

[0076] The present invention combines the prepared Cd@IIP paper-based imprinted material with a fluorescence signal output platform, uses it to measure a series of Cd(II) standard solutions with concentration gradients, and scans the fluorescence signals with a fluorescence microplate reader to obtain the corresponding fluorescence standard curve.

[0077] Figure 7 is the fluorescence quantitative analysis diagram of the paper-based cadmium ion imprinted fluorescence sensor of the present invention for cadmium ions with different concentrations. From Figure 7 it can be seen that in the concentration range of 0.01 - 10 μg mL -1 a calibration curve with R 2The linear standard curve with a value of 0.993 indicates a good linear relationship between the fluorescence intensity and the cadmium ion concentration. The detection limit (LOD) and quantification limit (LOQ) calculated by the paper-based cadmium ion-imprinted fluorescence sensor according to the formula are 14.58 nM and 42.1 nM, respectively. (LOD = 3SD / S, LOQ = 10SD / S, where SD is the standard deviation of the blank measurement value, and S is the slope of the standard curve. Here, LOD and LOQ represent the detection limit and quantification limit of this method. S / N is the ratio of the standard deviation S to the slope N of the standard curve).

[0078] The detection results show that the paper-based cadmium ion-imprinted fluorescence sensor integrating the AIE probe and the ion-imprinted polymer prepared by the present invention can not only enrich and detect cadmium ions, but also achieve rapid detection (30 min), with a detection limit of 14.58 nM.

[0079] Figure 8 is a visualization schematic diagram of the fluorescence response of the paper-based cadmium ion-imprinted fluorescence sensor of the present invention to cadmium ions at different concentrations. From Figure 8 it can be seen that as the cadmium ion concentration increases, the fluorescence intensity of the paper-based cadmium ion-imprinted fluorescence sensor also increases, and it can be distinguished by the naked eye under 254 nm ultraviolet light.

[0080] Figure 9 is the RGB analysis result of the fluorescence response of the paper-based cadmium ion-imprinted fluorescence sensor of the present invention to cadmium ions at different concentrations. From Figure 9 it can be seen that in order to achieve the visual analysis of cadmium ions, this platform is combined with a smart phone to form a rapid detection system. The RGB values are obtained by processing using Photoshop 19.0 software (Adobe Systems Software Ireland Ltd, USA). As the cadmium ion concentration increases, the R / G ratio increases, and a standard curve with an R 2 value of 0.957 is obtained. The calculated LOD and LOQ are 0.11 μg mL -1 and 0.37 μg mL -1 . Therefore, this method shows good application potential in the visual and rapid detection of cadmium ions.

[0081] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A paper-based cadmium ion-imprinted fluorescence sensor integrating AIE probe and ion-imprinted polymer, characterized in that, It includes a Cd@IIP paper-based imprinting material and an AIE probe solution; The preparation method of the Cd@IIP paper-based imprinting material is as follows: 1) Prepare 20 mL of a hydrochloric acid solution with a concentration of 0.2 mol / L. Immerse the blank paper-based FP in the hydrochloric acid solution for cleaning. After taking it out, wash it with ultrapure water until neutral, and dry it at 60 °C for 2 h to obtain the cleaned paper-based FP@OH; 2) Immerse the cleaned paper-based material in a 0.5% polyacrylic acid (PAA) solution. After ultrasonic treatment for 30 min, take it out, wash it with ultrapure water, and dry it at 60 °C for 2 h to obtain the polyacrylic acid-modified paper-based material FP@PAA; 3) Prepare 0.23 mmol of cadmium nitrate solution with an ethanol-water solution as the solvent. Add acetic acid and the functional monomer MPTES to the cadmium nitrate solution. The usage amount of acetic acid is 1.8 μmol, and the usage amount of the functional monomer is 3 mmol. After mixing evenly, carry out pre-polymerization at 60 °C for 3 h; 4) After the pre-polymerization is completed, add the cross-linking agent TEOS to the pre-polymerization solution. The usage amount of the cross-linking agent is 2.5 mmol. After ultrasonic treatment for 30 min, add the polyacrylic acid-modified paper-based material FP@PAA, and carry out the formal polymerization reaction at 60 °C for 18 h; 5) After the formal polymerization is completed, take it out and wash it with ethanol and ultrapure water respectively. When eluting the template of the constructed cadmium ion imprinting layer, the template eluent used is EDTA, nitric acid, and remove the residual elution solution with water. The concentration of EDTA is 0.1 mol / L, and the concentration of nitric acid is 0.2 mol / L. Wash it with ultrapure water and dry it at 60 °C for 2 h to obtain the Cd@IIP paper-based imprinting material; The preparation method of the AIE probe is as follows: Add 3 mmol of potassium carbonate, 1 mmol of 2,6-bis(chloromethyl)pyridine, 0.2 mmol of potassium iodide, and 2 mmol of 8-hydroxyquinoline to a 50 mL round-bottom flask for condensation reaction; the condensation reaction is carried out in 20 mL of acetone; the temperature of the condensation reaction is 70 °C; the time is 6 h.

2. The paper-based cadmium ion-imprinted fluorescence sensor integrating the AIE probe and the ion-imprinted polymer according to claim 1, wherein In step (3), when eluting the template of the constructed cadmium ion imprinting layer, the template eluent used is EDTA, nitric acid, or a combination of the two, and remove the residual elution solution with water. The concentration of EDTA is 50 mmol / L - 200 mmol / L, and the concentration of nitric acid is 0.2 mmol / L - 3 mmol / L.

3. The paper-based cadmium ion-imprinted fluorescence sensor integrating the AIE probe and the ion-imprinted polymer according to claim 1, wherein, The concentration of the AIE probe solution is 10 μmol / L - 200 μmol / L.

4. The detection method of the paper-based cadmium ion-imprinted fluorescence sensor integrating AIE probe and ion-imprinted polymer according to any one of claims 1-3, characterized in that, It includes the following steps: (1) Set a nitrocellulose membrane at the front end of the support, set the Cd@IIP paper-based imprinting material in the middle, and set a water-absorbing pad at the rear end to obtain a paper-based sensor; (2) Place the front end of the paper-based sensor in a test sample containing cadmium ions for sample loading; (3) After the sample loading is completed, remove the Cd@IIP paper-based imprinting material, wash it with ultrapure water, and dry it to obtain the dried Cd@IIP paper-based imprinting material; (4) Drop the AIE probe solution onto the dried Cd@IIP paper-based imprinted material, carry out the reaction, and perform quantitative analysis using fluorescence colorimetry.

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