Construction and application of a lead sulfide quantum dots-based controlled-release competitive electrochemiluminescence sensor

Abstract

This invention discloses the construction and application of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots, belonging to the fields of nanoscience, photoelectrochemistry, and sensing analysis technology. In this invention, mesoporous SiO2 is used as the controlled-release carrier, gold nanoparticles-antigens are bound to the SiO2 surface as blocking agents, and PbS quantum dots are encapsulated within the SiO2 as quenchers. Resonant energy transfer is achieved through the release of PbS quantum dots, leading to a decrease in the luminescence signal, thereby responding to biomolecular stimulation between the target and related antibodies. Due to the competition between the antigen and the standard substance, the significant decrease in signal is inversely proportional to the target concentration. Based on the introduction of the controlled-release, competitive, and resonant energy transfer strategy, the constructed electrochemiluminescence sensor exhibits high detection sensitivity and accuracy in target detection, with a linear range of 50 fg / mL to 1 μg / mL and a detection limit as low as 27.9 fg / mL, providing a feasible means for sensitive monitoring of pollutants in aquatic environments.

Description

Technical Field

[0001] This invention discloses the construction and application of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots, belonging to the fields of nanoscience, photoelectrochemistry, and sensing and analysis technology. Background Technology

[0002] Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a series of non-naturally synthesized organic compounds widely used in the textile, surfactant, and food packaging industries. They diffuse into environmental water through direct discharge and natural sedimentation. PFAS have long half-lives, are difficult to degrade, and can cause numerous adverse reactions after being ingested, posing a significant threat to human health. Therefore, achieving sensitive and efficient detection of emerging environmental pollutants such as PFAS is urgently needed. Currently, PFAS detection methods are mainly based on liquid chromatography and gas chromatography. In comparison, electrochemiluminescence (ECL) technology has advantages such as simple operation, fast analysis speed, and high sensitivity, making it an ideal method for PFAS detection.

[0003] Controlled release, as a strategy for delivering or releasing encapsulated substances, can achieve precise responses to changes in target concentration by triggering signal self-on or self-off effects through external stimuli such as pH, temperature, light, and biomolecules. Based on the controlled release strategy, strong signal changes are key to improving sensor sensitivity. Eu-MOFs, with their stable optical properties and tunable structure, can serve as ideal light emitters. Furthermore, the introduction of Eu... 3+ Energy level matching metal ions can achieve Eu 3+ To enhance the ECL signal of Eu-MOF, we introduce Bi to achieve stronger excitation. 3+ BiEu-MOF was synthesized as a luminescent material.

[0004] Resonant energy transfer can effectively trigger signal quenching of luminescent materials through energy transfer between the acceptor and donor. Semiconductor materials, with their wide absorption, narrow emission band, and high photostability, have the potential to perform energy transfer with luminescent materials. Furthermore, adjusting the size of semiconductor materials to the quantum dot level can improve energy transfer efficiency based on their large specific surface area, quantum size effect, and good dispersion. In this work, due to the various advantages of PbS quantum dots and the limited research on PbS quantum dots in the sensing field, they were chosen as a feasible quencher for achieving significant signal attenuation of luminescent materials.

[0005] This study constructed a PbS quantum dot-based controlled-release competitive ECL sensor for the sensitive detection of 6:2 fluoropolymer alcohols, using BiEu-MOF as the luminescent agent and SiO2 as the controlled-release carrier. PbS quantum dots, acting as quenchers, are encapsulated in mesoporous SiO2 via AuNPs-antigen blocking. When the 6:2 fluoropolymer alcohol antigen specifically binds to the 6:2 fluoropolymer alcohol antibody, the pores of the SiO2 carrier open, releasing the PbS quantum dots and achieving a significant signal self-closing effect. Furthermore, due to steric hindrance, the antibody binds to the 6:2 fluoropolymer alcohol standard more readily than the antigen, resulting in an inverse relationship between target concentration changes and PbS quantum dot release. Consequently, the sensor's ECL signal linearly increases with increasing 6:2 fluoropolymer alcohol concentration. Summary of the Invention

[0006] One of the technical tasks of this invention is to overcome the shortcomings of the prior art and introduce Bi 3+ As a sensitizing component, to enhance Eu 3+ The light emission was observed, and a BiEu-MOF with high ECL efficiency was synthesized as a light emitter, which improved the output signal of the sensing system.

[0007] The second technical objective of this invention is to construct a competitive ECL sensor based on PbS quantum dots based on a controlled release and resonant energy transfer strategy. This sensor has high detection sensitivity and accuracy, uses low-cost raw materials, has a simple preparation process, and is safe to operate.

[0008] The third technical objective of this invention is to provide an application for a controlled-release competitive ECL sensor based on PbS quantum dots constructed using the aforementioned method, specifically for trace monitoring of 6:2 fluorinated telomerol, a novel PFAS pollutant in environmental water, which has certain industrialization prospects.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] 1. Construction of a controlled-release competitive ECL sensor based on PbS quantum dots

[0011] The glassy carbon electrode was polished using Al2O3 slurry; 8–10 μL of BiEu-MOF solution was dropped onto the polished glassy carbon electrode surface; 8 μL of 6:2 fluoropolymer alcohol antibody solution was added dropwise, and the electrode was incubated at 4 °C for 1 h; 5 μL of bovine serum albumin solution was added dropwise to the modified electrode surface, and the electrode was incubated at 4 °C for 1 h to block non-specific sites; 6–8 μL of SiO2-Au NPs-antigen solution encapsulating PbS quantum dots and 6–8 μL of 6:2 fluoropolymer alcohol solution were added dropwise, and the electrode was incubated at 4 °C for 2 h, thus constructing a controlled-release competitive ECL sensor based on PbS quantum dots.

[0012] The BiEu-MOF is prepared by dissolving 146 mg of Bi(NO3)3·5H2O, 89 mg of Eu(NO3)3·6H2O, and 130 mg of 1,3-dicarboxy-5-benzenesulfonic acid monosodium salt in 30 mL of N,N-dimethylformamide, sonicating for 10 min to ensure complete dissolution, reacting the solution at 75 °C for 24 h, centrifuging, and washing several times with N,N-dimethylformamide to obtain BiEu-MOF.

[0013] The PbS quantum dots were prepared by dissolving 1.69 g of PbO in 19 mL of oleic acid and reacting at 150 °C for 1 h to prepare a lead oleate precursor solution; a mixed solution containing 0.2 mL of bis(trimethylsilylmethyl) sulfide and 20 mL of octadecene was rapidly injected into the lead oleate precursor solution at 150 °C; the resulting solution was reacted at 130 °C for 20 min; and the PbS quantum dots were obtained by alternating cycles of toluene dispersion and alcohol precipitation.

[0014] The SiO2 is prepared by dissolving 0.5 g of hexadecyltrimethylammonium bromide in 240 mL of ultrapure water and heating to 80 °C until it is completely dissolved; then slowly adding 6 mL of 0.5 M NaOH to the solution; after reacting for 30 min, adding a mixed solution of 2.5 g of tetraethoxysilane and 5 mL of anhydrous ethanol; centrifuging the resulting solution, washing it sequentially with anhydrous ethanol and ultrapure water, and drying it overnight at 60 °C; and finally reacting it at 550 °C for 5 h to obtain SiO2.

[0015] The Au NPs-antigen was prepared by diluting 1 mL of 1% HAuCl4·4H2O in 100 mL of ultrapure water; adding 2.5 mL of sodium citrate solution under vigorous stirring, and boiling for 10 min until the solution turned purple-red; continuing stirring for another 10 min yielded Au NPs; adding 200 μL of 1 μg / mL 6:2 fluoropolymer alcohol antigen to 10 mL of the prepared Au NPs solution, and incubating with shaking at 4 °C for 12 h; centrifuging the mixture at 4 °C for 30 min, and washing twice with phosphate buffer solution to obtain the Au NPs-antigen; the SiO2-Au encapsulated PbS quantum dots... The NPs-antigen was prepared by dispersing 200 mg of SiO2 and 300 mg of polyethyleneimine in 40 mL of ultrapure water, stirring for 6 h, washing with ultrapure water, and then vacuum drying at 60 °C to obtain aminated SiO2. AuNPs-antigen was dissolved in 1 mL of phosphate buffer solution, and 200 μL of 1% bovine serum albumin solution was added to obtain a bovine serum albumin-blocked active site AuNPs-antigen solution. 1 mg of PbS quantum dots and 2 mg of aminated SiO2 were dissolved in 2 mL of phosphate buffer solution, and then 10 mL of bovine serum albumin-blocked active site Au NPs-antigen solution was added. The mixture was incubated with shaking at 4 °C for 4 h, centrifuged, and washed with ultrapure water to obtain SiO2-Au NPs-antigen encapsulated with PbS quantum dots.

[0016] The 6:2 fluoropolymer alcohol solution is obtained by uniformly dispersing 6:2 fluoropolymer alcohol at concentrations of 50 fg / mL, 100 fg / mL, 1 pg / mL, 10 pg / mL, 100 pg / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL, and 1 μg / mL in a phosphate buffer solution with a pH of 7.4.

[0017] 2. The application of the controlled-release competitive ECL sensor based on PbS quantum dots constructed by the aforementioned method is for the detection of 6:2 fluoropolymer alcohol, a novel PFAS pollutant, in environmental water. A three-electrode system is constructed using an Ag / AgCl electrode as the reference electrode, a platinum electrode as the auxiliary electrode, and the constructed ECL sensor as the working electrode for signal testing. A phosphate buffer solution with pH 7.4 and containing 20–30 mg / mL K₂S₂O₈ is used as the detection solution. The applied scanning voltage range is -1.6–0 V, and the photomultiplier tube voltage is 800 V. Based on the measured ECL signal, a linear curve is plotted, revealing that the constructed controlled-release competitive ECL sensor has a detection range of 50 fg / mL to 1 μg / mL, with a detection limit as low as 27.9 fg / mL. It exhibits high stability, specificity, and reproducibility, making it suitable for trace monitoring of 6:2 fluoropolymer alcohol, a novel PFAS pollutant, in environmental water.

[0018] The beneficial technical effects of the present invention are as follows:

[0019] 1. This invention prepares a self-enhanced BiEu-MOF with high ECL efficiency as a light emitter, by introducing a material that interacts with Eu... 3+ Bi of energy level matching 3+ To achieve Eu 3+ The stronger excitation enhances the ECL emission of the luminescent material, thereby effectively improving the output signal of the sensor;

[0020] 2. This invention constructs a controlled-release competitive ECL sensor based on PbS quantum dots. Based on sensing strategies such as controlled release, resonant energy transfer, and competition between antigen and standard substances, the ECL signal of the constructed sensor is linearly and significantly enhanced with the increase of 6:2 fluoropolymer alcohol concentration, effectively improving the detection sensitivity and accuracy of the sensor.

[0021] 3. The controlled-release competitive ECL sensor based on PbS quantum dots constructed in this invention exhibits a wide linear range and low detection limit for the detection of 6:2 fluorinated telomeres in environmental water, as well as high stability, specificity, and reproducibility. It is suitable for dynamic trace monitoring of PFAS pollutants and has certain industrialization prospects. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the scope of protection of the present invention is not limited thereto. Any changes made to the technical solutions of the present invention by those skilled in the art should fall within the scope of protection of the present invention.

[0023] Example 1: Construction of a Controlled-Release Competitive ECL Sensor Based on PbS Quantum Dots

[0024] The glassy carbon electrode was polished using Al2O3 slurry; 8 μL of BiEu-MOF solution was dropped onto the polished glassy carbon electrode surface; 8 μL of 6:2 fluoropolymer alcohol antibody solution was added dropwise, and the electrode was incubated at 4 °C for 1 h; 5 μL of bovine serum albumin solution was added dropwise to the modified electrode surface, and the electrode was incubated at 4 °C for 1 h to block non-specific sites; 6 μL of SiO2-Au NPs-antigen solution encapsulating PbS quantum dots and 6 μL of 6:2 fluoropolymer alcohol solution were added dropwise, and the electrode was incubated at 4 °C for 2 h, thus constructing a controlled-release competitive ECL sensor based on PbS quantum dots.

[0025] The BiEu-MOF is prepared by dissolving 146 mg of Bi(NO3)3·5H2O, 89 mg of Eu(NO3)3·6H2O, and 130 mg of 1,3-dicarboxy-5-benzenesulfonic acid monosodium salt in 30 mL of N,N-dimethylformamide, sonicating for 10 min to ensure complete dissolution, reacting the solution at 75 °C for 24 h, centrifuging, and washing several times with N,N-dimethylformamide to obtain BiEu-MOF.

[0026] The PbS quantum dots were prepared by dissolving 1.69 g of PbO in 19 mL of oleic acid and reacting at 150 °C for 1 h to prepare a lead oleate precursor solution; a mixed solution containing 0.2 mL of bis(trimethylsilylmethyl) sulfide and 20 mL of octadecene was rapidly injected into the lead oleate precursor solution at 150 °C; the resulting solution was reacted at 130 °C for 20 min; and the PbS quantum dots were obtained by alternating cycles of toluene dispersion and alcohol precipitation.

[0027] The SiO2 is prepared by dissolving 0.5 g of hexadecyltrimethylammonium bromide in 240 mL of ultrapure water and heating to 80 °C until it is completely dissolved; then slowly adding 6 mL of 0.5 M NaOH to the solution; after reacting for 30 min, adding a mixed solution of 2.5 g of tetraethoxysilane and 5 mL of anhydrous ethanol; centrifuging the resulting solution, washing it sequentially with anhydrous ethanol and ultrapure water, and drying it overnight at 60 °C; and finally reacting it at 550 °C for 5 h to obtain SiO2.

[0028] The Au NPs-antigen was prepared by diluting 1 mL of 1% HAuCl4·4H2O in 100 mL of ultrapure water; adding 2.5 mL of sodium citrate solution under vigorous stirring, and boiling for 10 min until the solution turned purple-red; continuing stirring for another 10 min yielded Au NPs; adding 200 μL of 1 μg / mL 6:2 fluoropolymer alcohol antigen to 10 mL of the prepared Au NPs solution, and incubating with shaking at 4 °C for 12 h; centrifuging the mixture at 4 °C for 30 min, and washing twice with phosphate buffer solution to obtain the Au NPs-antigen; the SiO2-Au encapsulated PbS quantum dots... The NPs-antigen was prepared by dispersing 200 mg of SiO2 and 300 mg of polyethyleneimine in 40 mL of ultrapure water, stirring for 6 h, washing with ultrapure water, and then vacuum drying at 60 °C to obtain aminated SiO2. AuNPs-antigen was dissolved in 1 mL of phosphate buffer solution, and 200 μL of 1% bovine serum albumin solution was added to obtain a bovine serum albumin-blocked active site AuNPs-antigen solution. 1 mg of PbS quantum dots and 2 mg of aminated SiO2 were dissolved in 2 mL of phosphate buffer solution, and then 10 mL of bovine serum albumin-blocked active site Au NPs-antigen solution was added. The mixture was incubated with shaking at 4 °C for 4 h, centrifuged, and washed with ultrapure water to obtain SiO2-Au NPs-antigen encapsulated with PbS quantum dots.

[0029] The 6:2 fluoropolymer alcohol solution is obtained by uniformly dispersing 6:2 fluoropolymer alcohol at concentrations of 50 fg / mL, 100 fg / mL, 1 pg / mL, 10 pg / mL, 100 pg / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL, and 1 μg / mL in a phosphate buffer solution with a pH of 7.4.

[0030] Example 2: Construction of a PbS quantum dot-based controlled-release competitive ECL sensor

[0031] The glassy carbon electrode was polished using Al2O3 slurry; 9 μL of BiEu-MOF solution was dropped onto the polished glassy carbon electrode surface; 8 μL of 6:2 fluoropolymer alcohol antibody solution was added dropwise, and the electrode was incubated at 4 °C for 1 h; 5 μL of bovine serum albumin solution was added dropwise to the modified electrode surface, and the electrode was incubated at 4 °C for 1 h to block non-specific sites; 7 μL of SiO2-Au NPs-antigen solution encapsulating PbS quantum dots and 7 μL of 6:2 fluoropolymer alcohol solution were added dropwise, and the electrode was incubated at 4 °C for 2 h, thus constructing a controlled-release competitive ECL sensor based on PbS quantum dots.

[0032] The BiEu-MOF is prepared by dissolving 146 mg of Bi(NO3)3·5H2O, 89 mg of Eu(NO3)3·6H2O, and 130 mg of 1,3-dicarboxy-5-benzenesulfonic acid monosodium salt in 30 mL of N,N-dimethylformamide, sonicating for 10 min to ensure complete dissolution, reacting the solution at 75 °C for 24 h, centrifuging, and washing several times with N,N-dimethylformamide to obtain BiEu-MOF.

[0033] The PbS quantum dots were prepared by dissolving 1.69 g of PbO in 19 mL of oleic acid and reacting at 150 °C for 1 h to prepare a lead oleate precursor solution; a mixed solution containing 0.2 mL of bis(trimethylsilylmethyl) sulfide and 20 mL of octadecene was rapidly injected into the lead oleate precursor solution at 150 °C; the resulting solution was reacted at 130 °C for 20 min; and the PbS quantum dots were obtained by alternating cycles of toluene dispersion and alcohol precipitation.

[0034] The SiO2 is prepared by dissolving 0.5 g of hexadecyltrimethylammonium bromide in 240 mL of ultrapure water and heating to 80 °C until it is completely dissolved; then slowly adding 6 mL of 0.5 M NaOH to the solution; after reacting for 30 min, adding a mixed solution of 2.5 g of tetraethoxysilane and 5 mL of anhydrous ethanol; centrifuging the resulting solution, washing it sequentially with anhydrous ethanol and ultrapure water, and drying it overnight at 60 °C; and finally reacting it at 550 °C for 5 h to obtain SiO2.

[0035] The Au NPs-antigen was prepared by diluting 1 mL of 1% HAuCl4·4H2O in 100 mL of ultrapure water; adding 2.5 mL of sodium citrate solution under vigorous stirring, and boiling for 10 min until the solution turned purple-red; continuing stirring for another 10 min yielded Au NPs; adding 200 μL of 1 μg / mL 6:2 fluoropolymer alcohol antigen to 10 mL of the prepared Au NPs solution, and incubating with shaking at 4 °C for 12 h; centrifuging the mixture at 4 °C for 30 min, and washing twice with phosphate buffer solution to obtain the Au NPs-antigen; the SiO2-Au encapsulated PbS quantum dots... The NPs-antigen was prepared by dispersing 200 mg of SiO2 and 300 mg of polyethyleneimine in 40 mL of ultrapure water, stirring for 6 h, washing with ultrapure water, and then vacuum drying at 60 °C to obtain aminated SiO2. AuNPs-antigen was dissolved in 1 mL of phosphate buffer solution, and 200 μL of 1% bovine serum albumin solution was added to obtain a bovine serum albumin-blocked active site AuNPs-antigen solution. 1 mg of PbS quantum dots and 2 mg of aminated SiO2 were dissolved in 2 mL of phosphate buffer solution, and then 10 mL of bovine serum albumin-blocked active site Au NPs-antigen solution was added. The mixture was incubated with shaking at 4 °C for 4 h, centrifuged, and washed with ultrapure water to obtain SiO2-Au NPs-antigen encapsulated with PbS quantum dots.

[0036] The 6:2 fluoropolymer alcohol solution is obtained by uniformly dispersing 6:2 fluoropolymer alcohol at concentrations of 50 fg / mL, 100 fg / mL, 1 pg / mL, 10 pg / mL, 100 pg / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL, and 1 μg / mL in a phosphate buffer solution with a pH of 7.4.

[0037] Example 3: Construction of a PbS quantum dot-based controlled-release competitive ECL sensor

[0038] The glassy carbon electrode was polished using Al2O3 slurry; 10 μL of BiEu-MOF solution was dropped onto the polished glassy carbon electrode surface; 8 μL of 6:2 fluoropolymer alcohol antibody solution was added dropwise, and the electrode was incubated at 4 °C for 1 h; 5 μL of bovine serum albumin solution was added dropwise to the modified electrode surface, and the electrode was incubated at 4 °C for 1 h to block non-specific sites; 8 μL of SiO2-Au NPs-antigen solution encapsulating PbS quantum dots and 8 μL of 6:2 fluoropolymer alcohol solution were added dropwise, and the electrode was incubated at 4 °C for 2 h, thus constructing a controlled-release competitive ECL sensor based on PbS quantum dots.

[0039] The BiEu-MOF is prepared by dissolving 146 mg of Bi(NO3)3·5H2O, 89 mg of Eu(NO3)3·6H2O, and 130 mg of 1,3-dicarboxy-5-benzenesulfonic acid monosodium salt in 30 mL of N,N-dimethylformamide, sonicating for 10 min to ensure complete dissolution, reacting the solution at 75 °C for 24 h, centrifuging, and washing several times with N,N-dimethylformamide to obtain BiEu-MOF.

[0040] The PbS quantum dots were prepared by dissolving 1.69 g of PbO in 19 mL of oleic acid and reacting at 150 °C for 1 h to prepare a lead oleate precursor solution; a mixed solution containing 0.2 mL of bis(trimethylsilylmethyl) sulfide and 20 mL of octadecene was rapidly injected into the lead oleate precursor solution at 150 °C; the resulting solution was reacted at 130 °C for 20 min; and the PbS quantum dots were obtained by alternating cycles of toluene dispersion and alcohol precipitation.

[0041] The SiO2 is prepared by dissolving 0.5 g of hexadecyltrimethylammonium bromide in 240 mL of ultrapure water and heating to 80 °C until it is completely dissolved; then slowly adding 6 mL of 0.5 M NaOH to the solution; after reacting for 30 min, adding a mixed solution of 2.5 g of tetraethoxysilane and 5 mL of anhydrous ethanol; centrifuging the resulting solution, washing it sequentially with anhydrous ethanol and ultrapure water, and drying it overnight at 60 °C; and finally reacting it at 550 °C for 5 h to obtain SiO2.

[0042] The Au NPs-antigen was prepared by diluting 1 mL of 1% HAuCl4·4H2O in 100 mL of ultrapure water; adding 2.5 mL of sodium citrate solution under vigorous stirring, and boiling for 10 min until the solution turned purple-red; continuing stirring for another 10 min yielded Au NPs; adding 200 μL of 1 μg / mL 6:2 fluoropolymer alcohol antigen to 10 mL of the prepared Au NPs solution, and incubating with shaking at 4 °C for 12 h; centrifuging the mixture at 4 °C for 30 min, and washing twice with phosphate buffer solution to obtain the Au NPs-antigen; the SiO2-Au encapsulated PbS quantum dots... The NPs-antigen was prepared by dispersing 200 mg of SiO2 and 300 mg of polyethyleneimine in 40 mL of ultrapure water, stirring for 6 h, washing with ultrapure water, and then vacuum drying at 60 °C to obtain aminated SiO2. AuNPs-antigen was dissolved in 1 mL of phosphate buffer solution, and 200 μL of 1% bovine serum albumin solution was added to obtain a bovine serum albumin-blocked active site AuNPs-antigen solution. 1 mg of PbS quantum dots and 2 mg of aminated SiO2 were dissolved in 2 mL of phosphate buffer solution, and then 10 mL of bovine serum albumin-blocked active site Au NPs-antigen solution was added. The mixture was incubated with shaking at 4 °C for 4 h, centrifuged, and washed with ultrapure water to obtain SiO2-Au NPs-antigen encapsulated with PbS quantum dots.

[0043] The 6:2 fluoropolymer alcohol solution is obtained by uniformly dispersing 6:2 fluoropolymer alcohol at concentrations of 50 fg / mL, 100 fg / mL, 1 pg / mL, 10 pg / mL, 100 pg / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL, and 1 μg / mL in a phosphate buffer solution with a pH of 7.4.

[0044] Example 4 describes the application of a controlled-release competitive ECL sensor based on PbS quantum dots constructed using the methods described in Examples 1, 2, and 3. This sensor is used for the detection of 6:2 fluoropolymer alcohols, a novel PFAS pollutant, in environmental water. A three-electrode system is constructed using an Ag / AgCl electrode as the reference electrode, a platinum electrode as the auxiliary electrode, and the constructed ECL sensor as the working electrode for signal testing. A phosphate buffer solution with pH 7.4 and containing 20 mg / mL K₂S₂O₈ is used as the detection solution. The applied scanning voltage range is -1.6 to 0 V, and the photomultiplier tube voltage is 800 V. Based on the measured ECL signal, a linear curve is plotted, revealing that the constructed controlled-release competitive ECL sensor has a detection range of 50 fg / mL to 1 μg / mL, with a detection limit as low as 27.9 fg / mL. It exhibits high stability, specificity, and reproducibility, making it suitable for trace monitoring of 6:2 fluoropolymer alcohols, a novel PFAS pollutant, in environmental water.

[0045] Example 5 describes the application of a controlled-release competitive ECL sensor based on PbS quantum dots constructed using the methods described in Examples 1, 2, and 3. This sensor is used for the detection of 6:2 fluoropolymer alcohols, a novel PFAS pollutant, in environmental water. An Ag / AgCl electrode is used as the reference electrode, a platinum electrode as the auxiliary electrode, and the constructed ECL sensor as the working electrode, forming a three-electrode system for signal testing. A phosphate buffer solution with pH 7.4 and containing 25 mg / mL K₂S₂O₈ is used as the detection solution. The applied scanning voltage range is -1.6 to 0 V, and the photomultiplier tube voltage is 800 V. Based on the measured ECL signal, a linear curve is plotted, showing that the constructed controlled-release competitive ECL sensor has a detection range of 50 fg / mL to 1 μg / mL, with a detection limit as low as 27.9 fg / mL. It also exhibits high stability, specificity, and reproducibility, making it suitable for trace monitoring of 6:2 fluoropolymer alcohols, a novel PFAS pollutant, in environmental water.

[0046] Example 6 describes the application of a controlled-release competitive ECL sensor based on PbS quantum dots constructed using the methods described in Examples 1, 2, and 3. This sensor is used for the detection of 6:2 fluoropolymer alcohol, a novel PFAS pollutant, in environmental water. A three-electrode system is constructed using an Ag / AgCl electrode as the reference electrode, a platinum electrode as the auxiliary electrode, and the constructed ECL sensor as the working electrode for signal testing. A phosphate buffer solution with pH 7.4 and containing 30 mg / mL K₂S₂O₈ is used as the detection solution. The applied scanning voltage range is -1.6 to 0 V, and the photomultiplier tube voltage is 800 V. Based on the measured ECL signal, a linear curve is plotted, revealing that the constructed controlled-release competitive ECL sensor has a detection range of 50 fg / mL to 1 μg / mL, with a detection limit as low as 27.9 fg / mL. It exhibits high stability, specificity, and reproducibility, making it suitable for trace monitoring of 6:2 fluoropolymer alcohol, a novel PFAS pollutant, in environmental water. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the construction process of a controlled-release competitive ECL sensor based on PbS quantum dots (aminated SiO2: MSN; lead sulfide quantum dots: PbS QDs; 6:2 fluoropolymer alcohol: 6:2 FTOH).

[0048] Figure 2 The image shows the X-ray diffraction pattern of BiEu-MOF.

[0049] Figure 3 The image shows the infrared spectrum of BiEu-MOF.

[0050] Figure 4 The X-ray photoelectron spectra of BiEu-MOF are shown below, where (A) is the full-area X-ray photoelectron spectrum; (B) is the high-resolution X-ray photoelectron spectrum of the Eu3d region; and (C) is the high-resolution X-ray photoelectron spectrum of the Bi4f region.

[0051] Figure 5 Here are the scanning electron microscope images of (A) BiEu-MOF and (B) the corresponding elemental mapping diagram.

[0052] Figure 6 The image shows the X-ray diffraction pattern of PbS QDs.

[0053] Figure 7 The X-ray photoelectron spectra of PbS QDs are shown below, where (A) is the X-ray photoelectron spectrum of the entire region; (B) is the high-resolution X-ray photoelectron spectrum of the Pd4f region; and (C) is the high-resolution X-ray photoelectron spectrum of the S2p region.

[0054] Figure 8 This is a transmission electron microscope image of PbS QDs.

[0055] Figure 9 This is a scanning electron microscope image of MSN.

[0056] Figure 10 The images show (A) nitrogen adsorption-desorption isotherms and (B) pore size distribution of MSN.

[0057] Figure 11 The zeta potential diagrams are for (a) SiO2, (b) MSN, and (c) AuNPs.

[0058] Figure 12 ECL intensity-potential curves for BiEu-MOF / GCE and Eu-MOF / GCE.

[0059] Figure 13 The graph shows the fluorescence lifetime decay curves of BiEu-MOF and Eu-MOF.

[0060] Figure 14 ECL intensity-potential curves for BiEu-MOF / GCE and BiEu-MOF / PbS QDs / GCE.

[0061] Figure 15 Characterization diagram of the construction process of a PbS quantum dot-based controlled-release competitive ECL sensor based on (A) cyclic voltammetry and (B) electrochemical impedance spectroscopy.

[0062] Figure 16 The diagram shows the optimization results of the controlled-release competitive ECL sensor based on PbS quantum dots. (A) Optimization results of the pH of the test solution; (B) Optimization results of the BiEu-MOF concentration; (C) Optimization results of the antigen incubation time; (D) Optimization results of the K2S2O8 concentration.

[0063] Figure 17 The following are the ECL response curves (A) and (B) corresponding calibration curves of the PbS quantum dot-based controlled-release competitive ECL sensor after incubation with different concentrations of 6:2 FTOH. (a-i: 50 fg / mL, 100 fg / mL, 1 pg / mL, 10 pg / mL, 100 pg / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL, 1 μg / mL)

[0064] Figure 18 The following are the (A) stability (a~e: 50fg / mL, 100fg / mL, 10pg / mL, 100ng / mL, 1μg / mL), (B) reproducibility, and (C) selectivity of the controlled-release competitive ECL sensor based on PbS quantum dots.

Claims

1. Construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots, characterized in that, The glassy carbon electrode was polished using Al2O3 slurry. 8–10 μL of BiEu-MOF solution was dropped onto the polished glassy carbon electrode surface. 8 μL of a 6:2 fluoropolymer alcohol antibody solution was then added, and the electrode was incubated at 4 °C for 1 h. 5 μL of bovine serum albumin solution was added to the modified electrode surface, and the electrode was incubated at 4 °C for 1 h to block non-specific sites. 6–8 μL of SiO2-Au NPs-antigen solution encapsulating PbS quantum dots and 6–8 μL of a 6:2 fluoropolymer alcohol solution were then added, and the electrode was incubated at 4 °C for 2 h. This constructed a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots.

2. The construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots as described in claim 1, characterized in that, The BiEu-MOF is prepared by dissolving 146 mg of Bi(NO3)3·5H2O, 89 mg of Eu(NO3)3·6H2O, and 130 mg of 1,3-dicarboxy-5-benzenesulfonic acid monosodium salt in 30 mL of N,N-dimethylformamide, sonicating for 10 min to ensure complete dissolution, reacting the solution at 75 °C for 24 h, centrifuging, and washing several times with N,N-dimethylformamide to obtain BiEu-MOF.

3. The construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots as described in claim 1, characterized in that, The PbS quantum dots are prepared by dissolving 1.69g of PbO in 19mL of oleic acid and reacting at 150℃ for 1h to prepare a lead oleate precursor solution. A mixed solution containing 0.2 mL of bis(trimethylsilylmethyl) sulfide and 20 mL of octadecene was rapidly injected into the lead oleate precursor solution at 150 °C. The resulting solution was reacted at 130℃ for 20 min; PbS quantum dots were obtained by alternating cycles of toluene dispersion and alcohol precipitation.

4. The construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots as described in claim 1, characterized in that, The SiO2 is obtained by dissolving 0.5 g of hexadecyltrimethylammonium bromide in 240 mL of ultrapure water and heating it to 80 °C until it is completely dissolved; then slowly adding 6 mL of 0.5 M NaOH to the above solution; after reacting for 30 min, adding a mixed solution of 2.5 g of tetraethoxysilane and 5 mL of anhydrous ethanol; centrifuging the resulting solution, washing it sequentially with anhydrous ethanol and ultrapure water, and drying it overnight at 60 °C; and then reacting it at 550 °C for 5 h to obtain SiO2.

5. The construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots as described in claim 1, characterized in that, The AuNPs-antigen is prepared by diluting 1 mL of 1% HAuCl4·4H2O in 100 mL of ultrapure water; adding 2.5 mL of sodium citrate solution under vigorous stirring; and boiling for 10 min until the solution turns purple-red. Continue stirring for 10 min to obtain AuNPs; add 200 μL of 1 μg / mL 6:2 fluoropolymer alcohol antigen to 10 mL of the prepared AuNPs solution and incubate with shaking at 4 °C for 12 h; centrifuge the mixture at 4 °C for 30 min and wash twice with phosphate buffer solution to obtain AuNPs-antigen.

6. The construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots as described in claim 1, characterized in that, The SiO2-Au NPs-antigen encapsulated with PbS quantum dots is prepared by dispersing 200 mg of SiO2 and 300 mg of polyethyleneimine in 40 mL of ultrapure water, stirring for 6 h, washing with ultrapure water, and then vacuum drying at 60 °C to obtain aminated SiO2; dissolving the Au NPs-antigen in 1 mL of phosphate buffer solution and adding 200 μL of 1% bovine serum albumin solution to obtain a bovine serum albumin-blocked active site Au NPs-antigen solution; dissolving 1 mg of PbS quantum dots and 2 mg of aminated SiO2 in 2 mL of phosphate buffer solution, then adding 10 mL of bovine serum albumin-blocked active site Au NPs-antigen solution, shaking and incubating at 4 °C for 4 h, centrifuging, and washing with ultrapure water to obtain the SiO2-Au NPs-antigen encapsulated with PbS quantum dots.

7. The construction of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots as described in claim 1, characterized in that, The 6:2 fluoropolymer alcohol solution is obtained by uniformly dispersing 6:2 fluoropolymer alcohol at concentrations of 50 fg / mL, 100 fg / mL, 1 pg / mL, 10 pg / mL, 100 pg / mL, 1 ng / mL, 10 ng / mL, 100 ng / mL, and 1 μg / mL in a phosphate buffer solution with a pH of 7.

4.

8. The use of a controlled-release competitive electrochemiluminescence sensor based on PbS quantum dots constructed by the method described in claim 1, characterized in that, Applications for the detection of 6:2 fluoropolymer alcohols.

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