Method for detecting fe(iii) and dopamine

Abstract

This invention provides a method for detecting Fe(III) or dopamine (DA). The provided method, based on the individual Fe(III), combinations of dopamine (DA) and Fe(III), or combinations of ascorbic acid (AA) or Fe(III), can induce different, even opposite, PL or ECL signal responses in the thin-film detection electrode (CsPbBr3@SiO2 thin film). After preliminary analysis and detection of Fe(III) or dopamine based on the PL or ECL signals, the detection results of Fe(III) or dopamine can be further verified, ensuring the authenticity and reliability of the detection results and avoiding false positives / false negatives.

Description

Technical Field

[0001] This application relates to the field of molecular detection technology, and in particular to methods for detecting Fe(III) or dopamine (DA). Background Technology

[0002] Developing simple and efficient methods for detecting metal ions and bioactive molecules is of great significance for environmental protection and clinical diagnosis. This is especially true for Fe(III)(Fe 3+ Fe(III) detection is crucial in water quality monitoring because excessive Fe(III) levels in drinking water can lead to loss of appetite and gastrointestinal disorders. Furthermore, abnormal Fe(III) levels in the human body are closely associated with anemia, hemochromatosis, and Parkinson's disease; therefore, Fe(III) detection is essential for the medical diagnosis of these conditions.

[0003] Similarly, dopamine is a catecholamine neurotransmitter in the human nervous system, playing a crucial role in nerve signal transduction and brain function. Therefore, dopamine detection is of great significance for the early detection of dementia, Huntington's disease, and Parkinson's disease.

[0004] In recent years, molecular detection based on the response of specific molecules to light signals, electrical signals, and other signals has received increasing attention in the field of molecular detection. However, in practice, molecular detection results obtained based on the response of molecules to a single signal are prone to false positives / false negatives due to interference from other molecules with similar responses.

[0005] Therefore, developing more accurate molecular detection methods has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] CsPbBr3 nanocrystals (CsPbBr3 NCs) possess excellent photoluminescence (PL) and electrochemiluminescence (ECL) properties. During in-depth research, the inventors of this application discovered that individual Fe(III), combinations of dopamine (DA) and Fe(III), and combinations of ascorbic acid (AA) and Fe(III) can induce different, even opposite, PL and ECL signal responses in CsPbBr3 NCs, and based on this, the present invention was completed.

[0007] The first aspect of this invention provides a method for detecting Fe(III), comprising:

[0008] Prepare a thin-film detection electrode, which includes a conductive substrate electrode and a CsPbBr3@SiO2 thin film fixed on the surface of the conductive substrate electrode.

[0009] Prepare two first test sample solutions and a first blank control solution without Fe(III).

[0010] The thin-film detection electrode was immersed in the first blank control solution, and then a first photoluminescence (PL) detection was performed on the thin-film detection electrode to determine its emission peak intensity PL at a wavelength of 523 nm. 523 0 ;

[0011] The thin-film detection electrode was immersed in the first sample solution, and then a second photoluminescence detection was performed on the thin-film detection electrode to determine its emission peak intensity PL at a wavelength of 523 nm. 523 Fe ;

[0012] Add ascorbic acid (AA) to the second portion of the first test sample solution and dissolve it;

[0013] The thin-film detection electrode was immersed in a first sample solution containing ascorbic acid, and then a third photoluminescence detection was performed on the thin-film detection electrode to determine the emission peak intensity PL at a wavelength of 523 nm. 523 AA ;

[0014] In PL 523 Fe <PL 523 0 And PL 523 Fe <PL 523 AA In this case, it was determined that the first test sample solution contained Fe(III).

[0015] In this application, "first test sample solution" refers to a liquid in which the presence of Fe(III) needs to be detected. It can be a suitable liquid test sample, or it can be formed by dissolving a solid or liquid test sample in a suitable solvent, such as a weakly acidic buffer solution.

[0016] In this application, the "first blank control solution" refers to a liquid that does not contain Fe(III) and other substances that can affect PL detection. In one embodiment, when the first test sample solution is formed by dissolving a solid or liquid test sample in a suitable solvent, the suitable solvent can be directly used as the "first blank control solution". For example, the first blank control solution can be a weakly acidic buffer solution, preferably a buffer solution with pH 5.5, and more preferably an acetate-sodium acetate buffer solution with pH 5.5.

[0017] In this application, the emission peak intensity PL of the thin film detection electrode or CsPbBr3@SiO2 thin film electrode at a wavelength of 523 nm is... 523 This refers to the emission peak intensity of the PL spectrum of the CsPbBr3@SiO2 thin film at a wavelength of 523 nm under 365 nm ultraviolet light irradiation.

[0018] In this application, when it is mentioned that the thin film detection electrode is immersed in a blank control solution or a sample solution to be tested, it is usually necessary to ensure that the CsPbBr3@SiO2 thin film is immersed in the corresponding liquid.

[0019] In some implementations, the detection method further includes:

[0020] Prepare a third portion of the first test sample solution, and add dopamine (DA) to the third portion of the first test sample solution and dissolve it; immerse the thin-film detection electrode in the first test sample solution containing dopamine, and then perform a fourth photoluminescence detection on the thin-film detection electrode, and determine the emission peak intensity PL at a wavelength of 523 nm. 523 DA ;

[0021] In PL 523 Fe <PL 523 0 PL 523 Fe <PL 523 AA And PL 523 Fe >PL 523 DA In this case, it was determined that the first test sample solution contained Fe(III).

[0022] In this embodiment, Fe(III) was verified by AA and DA respectively, which can further ensure the accuracy of detection.

[0023] The first aspect of the present invention also provides another method for detecting Fe(III), comprising:

[0024] Prepare a thin-film detection electrode, which includes a conductive substrate electrode and a CsPbBr3@SiO2 thin film fixed on the surface of the conductive substrate electrode.

[0025] Prepare two first test sample solutions and a first blank control solution without Fe(III).

[0026] The thin-film detection electrode was immersed in the first blank control solution, and then the thin-film detection electrode was subjected to the first photoluminescence detection to determine its emission peak intensity PL at a wavelength of 523 nm.523 0 ;

[0027] The thin-film detection electrode was immersed in the first sample solution, and then a second photoluminescence detection was performed on the thin-film detection electrode to determine its emission peak intensity PL at a wavelength of 523 nm. 523 Fe ;

[0028] Dopamine was added to the second portion of the first test sample solution and dissolved; the thin-film detection electrode was immersed in the first test sample solution containing dopamine, and then a third photoluminescence detection was performed on the thin-film detection electrode to determine the emission peak intensity PL at a wavelength of 523 nm. 523 DA ;

[0029] In PL 523 0 >PL 523 Fe >PL 523 DA In this case, it was determined that the first test sample solution contained Fe(III).

[0030] In this embodiment, the detection method further includes:

[0031] Prepare a third portion of the first test sample solution, and add ascorbic acid (AA) to the third portion of the first test sample solution and dissolve it;

[0032] The thin-film detection electrode was immersed in a first sample solution containing ascorbic acid, and then a fourth photoluminescence detection was performed on the thin-film detection electrode to determine the emission peak intensity PL at a wavelength of 523 nm. 523 AA ;

[0033] In PL 523 Fe <PL 523 0 PL 523 Fe <PL 523 AA And PL 523 Fe >PL 523 DA In this case, it was determined that the first test sample solution contained Fe(III).

[0034] In this embodiment, Fe(III) was verified by DA and AA respectively, which can further ensure the accuracy of detection.

[0035] In the detection methods provided in the first aspect of the present invention, the concentration of ascorbic acid in the first test sample solution containing ascorbic acid is less than 0.2 mM.

[0036] In the detection methods provided in the first aspect of the present invention, the concentration of dopamine in the first test sample solution containing dopamine is less than 0.4 mM.

[0037] In the detection methods provided in the first aspect of the present invention, the detection methods are used to detect Fe(III) at concentrations below 0.8 mM.

[0038] A second aspect of the present invention provides a method for detecting dopamine, comprising the following steps:

[0039] Prepare a thin-film detection electrode, which includes a conductive substrate electrode and a CsPbBr3@SiO2 thin film fixed on the surface of the conductive substrate electrode.

[0040] Prepare two second test sample solutions containing 2-(dibutylamino)ethanol (DBAE), and a second blank control solution containing DBAE but without dopamine.

[0041] The thin-film detection electrode was immersed in the second blank control solution, and then the thin-film detection electrode was subjected to a first electrochemiluminescence (ECL) detection to determine its electrochemiluminescence intensity (ECL). 0 ;

[0042] The thin-film detection electrode is immersed in the first portion of the second sample solution, and then a second electrochemiluminescence detection is performed on the thin-film detection electrode to determine its electrochemiluminescence intensity (ECL). DA ;

[0043] This will cause the second sample solution to contain Fe(III);

[0044] The thin-film detection electrode was immersed in a second sample solution containing Fe(III), and then a third electrochemiluminescence detection was performed on the thin-film detection electrode to determine its electrochemiluminescence intensity (ECL). Fe ;

[0045] In ECL DA <ECL 0 And ECL DA <ECL Fe In the case of [condition], it is determined that the second test sample solution contains dopamine, and the concentration of dopamine is less than or equal to 1 μM.

[0046] In this application, "second test sample solution" refers to a liquid in which the presence of dopamine, especially dopamine at a concentration of 1 μM or less, needs to be detected. It can be a suitable liquid test sample, or it can be formed by dissolving a solid or liquid test sample in a suitable solvent, such as a weakly acidic buffer solution.

[0047] In addition, by adding an appropriate amount of DBAE (2-(dibutylamino)ethanol) to the second test sample solution (for example, to make the second test sample solution contain 10 mM DBAE) and dissolving it, a second test sample solution containing DBAE can be obtained.

[0048] In this application, the "second blank control solution" refers to a liquid containing DBAE (e.g., 10 mM DBAE) but without dopamine or other substances that can affect ECL detection. In one embodiment, when the second test sample solution is formed by dissolving a solid or liquid test sample in a suitable solvent, the suitable solvent, with DBAE dissolved in it, can be directly used as the "second blank control solution". For example, the second blank control solution can be a weakly acidic buffer solution with dissolved DBAE, preferably a buffer solution with pH 5.5, and more preferably an acetate-sodium acetate buffer solution with pH 5.5.

[0049] The detection method provided in the second aspect of the invention is particularly suitable for detecting extremely low concentrations, such as DA concentrations less than or equal to 1 μM. In other words, the detection method provided in the second aspect of the invention has significant advantages in detecting extremely low concentrations, such as DA concentrations less than or equal to 1 μM.

[0050] In the detection method provided in the second aspect of the present invention, the concentration of Fe(III) in the second test sample solution containing Fe(III) is 0.2-0.8 mM, preferably 0.4 mM.

[0051] In the detection methods provided in the first and second aspects of the present invention, the first test sample solution and the second test sample solution are weakly acidic buffer solutions, preferably buffer solutions with pH 5.5, and more preferably acetate-sodium acetate buffer solutions with pH 5.5.

[0052] In the detection methods provided in the first and second aspects of this invention, the thin-film detection electrode used is prepared by the following method:

[0053] Preparation of CsPbBr3@SiO2 aqueous dispersion system

[0054] The CsPbBr3@SiO2 aqueous dispersion was coated onto the surface of a conductive substrate electrode and dried to obtain the thin film detection electrode.

[0055] In this application, CsPbBr3@SiO2 can be understood as a complex of CsPbBr3 and SiO2, wherein SiO2 coats CsPbBr3. Numerous reports have been published in the art regarding CsPbBr3@SiO2. Therefore, this application limits the methods for its preparation.

[0056] The CsPbBr3@SiO2 aqueous dispersion system refers to the dispersion obtained by dispersing CsPbBr3@SiO2 nanocrystals in water.

[0057] For example, the CsPbBr3@SiO2 aqueous dispersion system can be prepared by the following method:

[0058] 1) In an inert atmosphere, cesium carbonate (Cs2CO3), oleic acid (OA), and 1-octadecene (ODE) are mixed and heated until the cesium carbonate is completely dissolved into a transparent solution to obtain the cesium oleate precursor;

[0059] 2) PbBr2, 1-octadecene (ODE), oleic acid (OA) and oleylamine (OAm) were mixed and heated in an inert atmosphere until PbBr2 was completely dissolved; then cesium oleate precursor was added to it, the reaction was carried out for 5-15 seconds, cooled and centrifuged to obtain CsPbBr3 nanocrystal precipitate.

[0060] The obtained CsPbBr3 nanocrystals were dispersed in a solvent, and tetramethoxysilane (TMOS) and CsBr aqueous solution were added. The reaction was carried out at room temperature in the dark for 10-20 hours. After the reaction was completed, the nanocrystals were separated by centrifugation, and the resulting precipitate was CsPbBr3@SiO2 nanocrystals.

[0061] 3) The CsPbBr3@SiO2 nanocrystals were redispersed in water to obtain the CsPbBr3@SiO2 aqueous dispersion system.

[0062] In this application, there are no particular limitations on the conductive substrate electrode, as long as it has conductive properties. For example, glassy carbon electrodes, conductive glass electrodes, and ITO electrodes can be used as conductive substrate electrodes.

[0063] Beneficial effects

[0064] This invention provides a method for detecting Fe(III). This method is based on the fact that Fe(III) alone, Fe(III) acting in synergy with AA, and Fe(III) acting in synergy with DA can generate different or even opposite PL signals on a thin-film detection electrode (CsPbBr3@SiO2 thin film). After preliminary analysis and detection of Fe(III) based on the PL signal, the detection results of Fe(III) can be further verified by the specific changes in the PL signal of the thin-film detection electrode generated by Fe(III) acting in synergy with AA and / or Fe(III) acting in synergy with DA. This ensures the authenticity and reliability of the Fe(III) detection results and avoids the occurrence of false positives / false negatives.

[0065] In another aspect, this invention provides a method for detecting dopamine. This method is based on dopamine alone. Dopamine that acts synergistically with Fe(III) can cause different or even opposite ECL signals to be generated by a thin-film detection electrode pair. After preliminary molecular detection of DA based on the ECL signal, the specific changes in the ECL signal of the thin-film detection electrode caused by dopamine acting synergistically with Fe(III) can further verify the detection results of dopamine, ensuring the authenticity and reliability of the molecular detection results of dopamine and avoiding the occurrence of false positives / false negatives. Attached Figure Description

[0066] Figure 1 Image (A) shows the X-ray diffraction pattern of the CsPbBr3@SiO2 thin film;

[0067] Figure 1 (B) shows the Fourier transform infrared spectrum of the CsPbBr3@SiO2 thin film;

[0068] Figure 1 Image C shows a transmission electron microscope image of the CsPbBr3@SiO2 thin film;

[0069] Figure 1 Image (D) shows a high-resolution transmission electron microscope image of the CsPbBr3@SiO2 thin film;

[0070] Figure 2 (A) shows the UV extinction (blue line) and PL (red line) spectra of the CsPbBr3@SiO2 aqueous dispersion system (inset: photograph of the CsPbBr3@SiO2 aqueous dispersion system under ultraviolet light);

[0071] Figure 2 (B) shows the UV extinction (blue line) and PL (red line) spectra of the CsPbBr3@SiO2 film (inset: photograph of the CsPbBr3@SiO2 film dispersion under ultraviolet light);

[0072] Figure 2 Figure (C) shows the scanning speed at 100 mV / s. -1 Under the specified conditions, ECL curves of CsPbBr3@SiO2 thin films and bare GCE in different buffer solutions were obtained.

[0073] Figure 2 Figure (D) shows the scanning speed at 100 mV / s. -1 Under the specified conditions, the CV curves of CsPbBr3@SiO2 thin films and bare GCE in different buffer solutions were obtained.

[0074] Figure 3 (A) shows the PLC of CsPbBr3@SiO2 films and CsPbBr3 films in pH 5.5 buffer solution. 523 Changes over time;

[0075] Figure 3 (B) shows the change in ECL strength of CsPbBr3@SiO2 film and CsPbBr3 film in pH 5.5 buffer solution over time;

[0076] Figure 4 Figure (A) shows the photoluminescence (PL) spectra of CsPbBr3@SiO2 films under 365 nm UV irradiation in buffer solutions containing 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.5, and 0.8 mM Fe(III) at pH 5.5. Inset: PL spectra of CsPbBr3@SiO2 films. 523 With changes in Fe(III) concentration;

[0077] Figure 4 (B) shows the performance of the CsPbBr3@SiO2 film when switching between pH 5.5 buffer containing 0 or 0.4 mM Fe(III). 523 Changes;

[0078] Figure 5 Figure (A) shows the photoluminescence (PL) spectra of CsPbBr3@SiO2 films immersed in a pH 5.5 buffer solution containing 0.04, 0.08, 0.12, 0.16, and 0.2 mM Fe(III) under 365 nm UV irradiation. Inset: PL spectra of CsPbBr3@SiO2 films. 523 Dependence of different concentrations of AA in pH 5.5 buffer containing 0.4 mM Fe(III);

[0079] Figure 5(B) shows the performance of the CsPbBr3@SiO2 film when switching between pH 5.5 buffer containing 0.4 mM Fe(III) and 0 or 0.2 mM AA. 523 Changes;

[0080] Figure 6 Image (A) shows the PL of the CsPbBr3@SiO2 thin film. 523 With changes in Fe(II)(a) and AA concentrations (b);

[0081] Figure 6 (B) shows the UV-Vis absorption spectra of CsPbBr3@SiO2 thin films containing (a) 0.4 mM Fe(III) + 0.2 mM AA, (b) 0.4 mM MFe(III), and (c) 0.4 mM Fe(III) + 0.2 mM DA in buffer solutions; (d) shows the excitation spectrum and (e) shows the photoemission spectrum of the CsPbBr3@SiO2 thin films.

[0082] Figure 7 Figure (A) shows the PL of CsPbBr3@SiO2 films in buffer solutions containing different concentrations of DA. 523 Changes;

[0083] Figure 7 Figure (B) shows the photoluminescence (PL) spectra of CsPbBr3@SiO2 films under 365 nm UV irradiation in buffer solutions containing 0.4 mM Fe(III) and 0, 0.05, 0.1, 0.2, 0.3, and 0.4 mM DA. Inset: PL spectra of CsPbBr3@SiO2 films in buffer solutions containing 0.4 mM Fe(III). 523 With changes in DA concentration;

[0084] Figure 8 (A) shows the ECL strength of CsPbBr3@SiO2 films in different concentrations of DA in a buffer solution containing 10 mM DBAE;

[0085] Figure 8 (B) shows the changes in the ECL signal of the CsPbBr3@SiO2 film when the DA concentration was switched to 0 and 1 μM in pH 5.5 buffer.

[0086] Figure 9 (A) shows the ECL signals of CsPbBr3@SiO2 films in buffer solutions containing (a) 10 mM DBAE, (b) 0.4 mM Fe(III), (c) 0.4 mM Fe(III) + 1 μM DA, and (d) 0.4 mM Fe(III) + 0.2 mM DA in buffer solutions containing 10 mM DBAE.

[0087] Figure 9 Figure (B) shows the change in ECL of CsPbBr3@SiO2 films when switching between pH 5.5 buffer containing 1 μM DA or 0.4 mM Fe(III) + 1 μM DA. Detailed Implementation

[0088] To make the objectives, technical solutions, and advantages of this invention clearer, the following detailed description is provided with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in this application are within the scope of protection of this application.

[0089] It should be noted that, unless otherwise specified in the following examples, the conditions should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0090] Preparation of CsPbBr3@SiO2 thin film electrode

[0091] (1) Preparation of CsPbBr3@SiO2 aqueous dispersion system

[0092] Under N2 atmosphere, 0.2035 g Cs2CO3, 625 μL OA and 10 mL ODE were mixed in a 25 mL three-necked flask and heated at 120 °C for 30 minutes. Then, under N2 atmosphere, the mixture was heated to 140 °C until a clear cesium oleate precursor solution was obtained.

[0093] Add 1 mL of OAm, 1 mL of OA, 10 mL of ODE, and 0.2 mmol of PbBr2 to a flask. After purging with nitrogen to remove oxygen for half an hour, heat at 120 °C for 40 minutes, then heat to 140 °C until PbBr2 is completely dissolved. At this temperature, add 2.2 mL of preheated precursor solution (the solution is clear and free of precipitate after preheating). After reacting for 10 seconds, cool the mixture in an ice-water bath and centrifuge at 7000 rpm for 5 minutes to obtain the precipitate Cs4PbBr6 NCs.

[0094] The resulting precipitate was dispersed in n-hexane (12.5 mg / mL). -116 μL of TMOS was added to 4 mL of Cs4PbBr6NCs hexane solution and mixed thoroughly. Then, 160 μL of 0.1 M CsBr aqueous solution was added, and the mixture was stirred vigorously for 5 minutes. The mixture was then stored at room temperature in the dark and without external interference for 12 hours. The product was centrifuged at 2500 rpm to remove impurities. The remaining precipitate obtained after centrifugation at 13000 rpm was the final product, namely SiO2-coated CsPbBr3 NCs (abbreviated as CsPbBr3@SiO2 NCs).

[0095] CsPbBr3@SiO2 NCs were redispersed in water to obtain a concentration of 5 mg / mL. -1 CsPbBr3@SiO2 aqueous dispersion system.

[0096] (2) Preparation of CsPbBr3@SiO2 thin film electrode

[0097] CsPbBr3@SiO2 aqueous dispersion (5 mg mL) -1 The coating is applied to the polished glassy carbon electrode (GCE) surface and then allowed to dry naturally for 1 hour to form a CsPbBr3@SiO2 thin film on the glassy carbon electrode, thus obtaining a CsPbBr3@SiO2 thin film electrode.

[0098] Characterization of CsPbBr3@SiO2 thin film electrode

[0099] The successful preparation of CsPbBr3NCs and the successful coating of SiO2 were verified by XRD (X-ray diffraction), TEM (transmission electron microscopy), HRTEM (high-resolution transmission electron microscopy), UV-vis (ultraviolet-visible spectrophotometry), PL (photoluminescence spectroscopy), and FTIR (infrared spectroscopy).

[0100] Figure 1 (A) shows the XRD pattern of CsPbBr3@SiO2. The sharp peaks in the figure indicate the high crystallinity of CsPbBr3@SiO2. It has high peak intensities in the (100), (110) and (200) planes, indicating that CsPbBr3 NCs were successfully prepared and the addition of SiO2 did not affect its structure.

[0101] Figure 1 (B) shows the FTIR spectrum of the CsPbBr3@SiO2 thin film. Compared with pure CsPbBr3 NCs, the FTIR spectrum of CsPbBr3@SiO2 NCs shows that at 1100 cm⁻¹... -1 There is an absorption peak nearby, which is assigned to the Si-O bonding peak, indicating that SiO2 was successfully coated.

[0102] Figure 1(C) is a TEM image of the CsPbBr3@SiO2 thin film, which clearly shows that each cube of CsPbBr3NCs is covered by SiO2, while this is not observed in CsPbBr3NCs without SiO2. Figure 1 (Illustration in (C)).

[0103] Figure 1 Image D shows an HRTEM image of the CsPbBr3@SiO2 thin film, clearly displaying a lattice spacing of 2.8 and 1.5 mm. The (200) and (-110) planes corresponding to CsPbBr3 NCs.

[0104] All results indicate that CsPbBr3@SiO2 NCs were successfully prepared.

[0105] Figure 2 In the middle (A), the UV extinction (blue line) and PL (red line) spectra of the CsPbBr3@SiO2 aqueous dispersion system (inset: photograph of the CsPbBr3@SiO2 aqueous dispersion system under ultraviolet light) are shown. Figure 2 (B) shows the UV extinction (blue line) and PL (red line) spectra of the CsPbBr3@SiO2 thin film (inset: photograph of the CsPbBr3@SiO2 thin film dispersion under ultraviolet light). Figure 2 As shown in Figure (B), the film emits green fluorescence under ultraviolet light irradiation, with the maximum emission peak at 523 nm (excitation wavelength 365 nm), and the maximum UV-vis extinction intensity observed at 521 nm. The results are basically consistent with the UV-vis and PL results for the CsPbBr3@SiO2 aqueous dispersion system. Figure 2 (A) indicates that the CsPbBr3@SiO2 film continues the properties of CsPbBr3@SiO2 NCs.

[0106] Figure 2 Figure (C) shows the ECL spectra of CsPbBr3@SiO2 films and bare GCEs in buffer solutions containing 0 mM or 10 mM 2-(dibutylamino)ethanol (DBAE) as co-reactants, with an initial emission of approximately +0.75 V and a maximum emission of approximately +1.04 V at the anode. As can be seen from the figure, the ECL intensity of the CsPbBr3@SiO2 film is enhanced tenfold in the presence of the co-reactant DBAE, while the ECL signal on the bare GCE in the same solution is very weak.

[0107] Figure 2 Figure (D) shows the CV curves of CsPbBr3@SiO2 films and bare GCE in buffer solutions containing 0 mM or 10 mM DBAE as co-reactants.

[0108] Figure 2 The CV curves in (D) reveal a similar trend, demonstrating that DBAE plays a crucial role in generating a strong ECL signal in CsPbBr3@SiO2 films. All these results indicate that SiO2 successfully coats CsPbBr3 NCs, and the prepared CsPbBr3@SiO2 NCs maintain excellent optical and electrochemical properties.

[0109] Furthermore, the SiO2 coating plays a crucial role in the stability of the CsPbBr3@SiO2 film. Without SiO2, after the same testing time, the emission peak intensity (PL) of the CsPbBr3 film at 523 nm was significantly higher. 523 It is only 50% of the thickness of CsPbBr3@SiO2 thin films. Figure 3 (A)). Regarding the ECL signal, under the same scanning conditions as the CsPbBr3@SiO2 film, the ECL signal of the CsPbBr3 film almost disappeared. Figure 3 (B) This indicates that the coating effect of SiO2 enables the PL and ECL signals of the CsPbBr3@SiO2 film to maintain good stability in the buffer solution. In addition, the viscosity of SiO2 is beneficial for fixing CsPbBr3 NCs to form a CsPbBr3@SiO2 film on the electrode surface, without the need for additional polymers to fix and stabilize the nanomaterials on the electrode surface.

[0110] PL characteristics of CsPbBr3@SiO2 thin films

[0111] 1. PL characteristics of CsPbBr3@SiO2 thin films in the presence of Fe(III)

[0112] PL testing methods and procedures:

[0113] A glassy carbon electrode (thin-film detection electrode) coated with a CsPbBr3@SiO2 film was fixed on a glass slide and placed in a cuvette containing an acetate-sodium acetate buffer solution. The incident wavelength was set to 365 nm, and Fe(III) was added to the buffer solution to adjust the Fe(III) concentration for photoluminescence testing. During the switching test experiment, the glass slide with the fixed thin-film detection electrode was alternately placed in a cuvette containing Fe(III) and a buffer solution without Fe(III) for photoluminescence detection.

[0114] Test results:

[0115] In a buffer solution at pH 5.5, the photoluminescence (PL) spectrum of the CsPbBr3@SiO2 film exhibits sensitivity to Fe(III). As the Fe(III) concentration increases from 0 to 0.8 mM, the PL of the CsPbBr3@SiO2 film...523 The intensity decreases linearly. Figure 4 (A)). Furthermore, this attenuation of the PL signal is reversible. When the film is moved from a Fe(III)-containing solution to another Fe(III)-free solution, the PL... 523 It will return to its original state, indicating that the structure of the film is not affected by Fe(III). If the CsPbBr3@SiO2 film is placed in a buffer solution without Fe(III) in PL... 523 Defined as open, the film is placed in a PL buffer solution containing 0.4 mM Fe(III) 523 Defined as off, when the membrane is alternately placed in two different solutions, PL 523 The response behavior can be repeated at least 6 times. Figure 4 (B)

[0116] 2. AA-sensitive PL properties of CsPbBr3@SiO2 thin films

[0117] PL testing methods and procedures:

[0118] A glassy carbon electrode (thin-film detection electrode) coated with a CsPbBr3@SiO2 film was fixed on a glass slide and placed in a cuvette containing an acetate-sodium acetate buffer solution of 0.4 mM Fe(III). Alcohol (AA) was added to adjust the AA concentration in the buffer solution for photoluminescence testing. During the switching test experiment, the glass slide with the fixed thin-film electrode was alternately placed in a cuvette containing only Fe(III) and a buffer solution containing Fe(III) + AA for photoluminescence detection.

[0119] Test results:

[0120] In a buffer solution containing 0.4 mM Fe(III), the PL of the CsPbBr3@SiO2 film increased with increasing concentration of reducing agent AA in the Fe(III)-containing solution. 523 It can vary with the concentration of AA (c) AA Linear recovery from 0 to 0.2mM to the initial state ( Figure 5 A). When the film is alternately immersed in two solutions containing Fe(III) + AA and Fe(III) alone, PL 523 It will switch between on and off states, and this switching behavior can be repeated at least 6 times. Figure 5 B).

[0121] Through further experiments, the inventors discovered that the PL of the thin film... 523 The value is not sensitive to AA or Fe(II). Figure 6(A)). Based on this analysis, the recovery of the PL signal is attributed to the reduction of Fe(III) by AA. The sensitivity of the PL signal to the Fe(III) concentration may be due to the internal filtration effect. This is also supported by UV-Vis spectroscopy experiments, which show that the absorption range of Fe(III) in the buffer solution largely overlaps with the PL excitation peak (365 nm) of the CsPbBr3@SiO2 film. Figure 6 (See curves B and d). When 0.2 mM AA was added, the solution showed very low UV absorption at 365 nm. Figure 6 B, curve a), indicates that Fe(III) was almost completely reduced, leading to the reduction of PLC in the CsPbBr3@SiO2 film. 523 recover.

[0122] Therefore, the PL signal of the CsPbBr3@SiO2 thin film electrode, more specifically, the CsPbBr3@SiO2 thin film on this electrode, exhibits different or even opposite sensitive responses to Fe(III) alone and Fe(III) synergistically interacting with AA. Based on this phenomenon, accurate detection of the presence of Fe(III) in the sample solution can be achieved.

[0123] 3. DA-sensitive PL properties of CsPbBr3@SiO2 thin films

[0124] PL testing methods and procedures:

[0125] A glassy carbon electrode (thin film detection electrode) coated with a CsPbBr3@SiO2 film was fixed on a glass slide and placed in a cuvette containing only DA buffer solution. The DA concentration in the buffer solution was adjusted to perform photoluminescence testing. The electrode was fixed on a glass slide and placed in a cuvette containing a 0.4 mM Fe(III) buffer solution. DA was then added to the cuvette, and the DA concentration was adjusted to perform photoluminescence testing.

[0126] Test results:

[0127] The PL signal of the CsPbBr3@SiO2 thin film did not respond to the DA signal present alone in the solution. Figure 7 In the presence of Fe(III), the PL of the CsPbBr3@SiO2 film increases with increasing DA concentration. 523 Significantly reduced ( Figure 7 (B)). After adding 0.2 mM DA to 0.4 mM MFe(III) solution, PL 523The signal was reduced to 25% of the original signal (inset in Figure (B)). Based on this analysis, it is possible that the UV-Vis absorption range of the DA oxidation product overlaps with the PL emission peak of the CsPbBr3@SiO2 film at 523 nm, resulting in fluorescence resonance energy transfer, which further quenches the PL signal of the CsPbBr3@SiO2 film.

[0128] Therefore, the PL signal of the CsPbBr3@SiO2 thin film electrode, more specifically, the CsPbBr3@SiO2 thin film on this electrode, exhibits different or even opposite sensitive responses to Fe(III) alone and Fe(III) in synergy with DA. Based on this, accurate detection of the presence of Fe(III) in the sample solution can be achieved.

[0129] ECL properties of CsPbBr3@SiO2 thin films

[0130] 1. DAP-sensitive ECL properties of CsPbBr3@SiO2 thin films

[0131] ECL testing methods and procedures:

[0132] The ECL test was conducted with the photomultiplier tube voltage set to 600V and the amplification factor to 3x. A traditional three-electrode system was used, with the constructed CsPbBr3@SiO2 thin-film electrode, platinum wire, and silver / silver chloride electrode serving as the working electrode, counter electrode, and reference electrode, respectively. The test was performed in an electrolytic cell containing a buffer solution of 10mM DBAE, with different concentrations of DA added for ECL testing. During the switching test, the thin-film electrode was sequentially placed in electrolytic cells containing and without DA for electrochemiluminescence detection.

[0133] Test results:

[0134] The ECL signal of the CsPbBr3@SiO2 thin film decreases with increasing DA concentration, reaching a plateau at 0.1 mM. Figure 8 As shown in (A). Compared to the PL signal, which has no response to DA ( Figure 7 In the presence of DBAE, even with the addition of 1 μMDA, the ECL of the CsPbBr3@SiO2 film showed a decrease of approximately 50%. Figure 8 (A) If the ECL signal of a CsPbBr3@SiO2 film containing 1 μM DA is defined as off, and the ECL signal without DA is defined as on, and the film is placed in two solutions containing and without 1 μM DA respectively, the ECL will switch between the two states, and the repeatability is good. Figure 8 (B)

[0135] Fe(III)-sensitive ECL properties of CsPbBr3@SiO2 thin films

[0136] ECL testing methods and procedures:

[0137] The ECL test setup was the same as above. The constructed CsPbBr3@SiO2 thin-film electrode, platinum wire, and silver / silver chloride electrode were used as the working electrode, counter electrode, and reference electrode, respectively. The ECL signals were measured in buffer solutions containing only 10 mM DBAE; buffer solutions containing 0.4 mM MFe(III) + 10 mM DBAE; buffer solutions containing 0.4 mM Fe(III) + 1 μM DA + 10 mM DBAE; and buffer solutions containing 0.4 mM Fe(III) + 0.4 mM DA + 10 mM DBAE. During the switching test, the thin-film electrode was sequentially placed in buffer solutions containing 0.4 mM Fe(III) + 1 μM DA + 10 mM DBAE and buffer solutions containing 0.4 mM MFe(III) + 10 mM DBAE for electrochemiluminescence detection.

[0138] Test results:

[0139] Experiments revealed that the addition of Fe(III) had varying effects on the ECL signal under different concentrations of DA. For example... Figure 8 As shown, when 1 μM DA is present but no Fe(III) is present, the ECL signal of the film decreases by 50%. When 0.4 mM Fe(III) is added to the solution containing 1 μM DA, the ECL signal of the CsPbBr3@SiO2 film recovers. Figure 9 (A), Curve c). When the thin-film electrode is alternately immersed in two solutions containing 0.4 mM Fe(III) + 1 μM DA and only 1 μM DA, the ECL signal switches between on and off states, and the switching behavior can be repeated at least 6 times. Figure 9 (B) Regarding the reason why the addition of Fe(III) to a 1 μM DA solution restores the ECL signal, based on the previous analysis, it is believed that the excessively high Fe(III) concentration accelerates the oxidation of extremely low concentrations of DA. Therefore, it does not lead to the formation of electrochemical oxidation products (DA) on the electrode surface. ·+ It will not consume the active intermediate of the co-reactant (DBAE). · The ECL signal was maintained by adding 0.4 mM Fe(III) to a solution containing a high concentration of DA (0.2 mM). However, when 0.4 mM Fe(III) was added to the solution, the ECL signal of the CsPbBr3@SiO2 film not only failed to recover, but instead continued to decline to its original state. Figure 9 10% of (A) and (b) of curve ( Figure 9(A), curve d). Based on this analysis, this is because at higher DA concentrations, the content of DA oxidation products generated from Fe(III) and DA is high, which can absorb the electrochemiluminescence signal of the film through electrochemiluminescence resonance energy transfer. However, at 1 μM DA, the concentration of this product is very low, and electrochemiluminescence resonance energy transfer does not occur, thus the signal can be recovered. The UV-Vis signal from the mixture of 0.2 mM DA and 0.4 mM Fe(III) is shown in Figure 1. Figure 6 As can be seen from curve (B) and curve (c), the main oxidation product of DA absorbs the energy from the excited state to the ground state of the excited state product (CsPbBr3@SiO2*) of CsPbBr3@SiO2, and undergoes an electrochemiluminescence resonance energy transfer process, resulting in ECL quenching.

[0140] Therefore, the ECL signal of the CsPbBr3@SiO2 thin film electrode, more specifically, the CsPbBr3@SiO2 thin film on this electrode, exhibits different or even opposite sensitive responses to DA alone and DA synergistically with Fe(III). Based on this, it is possible to detect the presence of DA in the sample solution. Especially for low concentrations of DA, such as when the DA concentration is less than 1 μM, other detection methods may fail to achieve reliable detection due to sensitivity issues. However, the experiments described above demonstrate that the ECL based on the CsPbBr3@SiO2 thin film can reliably detect specific changes in DA concentrations below 1 μM.

[0141] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for detecting Fe(III), characterized in that, include: Prepare a thin-film detection electrode, which includes a conductive substrate electrode and a CsPbBr3@SiO2 thin film fixed on the surface of the conductive substrate electrode. Prepare two first test sample solutions and a first blank control solution without Fe(III). The thin-film detection electrode was immersed in the first blank control solution, and then a first photoluminescence (PL) detection was performed on the thin-film detection electrode to determine its emission peak intensity PL at a wavelength of 523 nm. 523 0 ; The thin-film detection electrode was immersed in the first sample solution, and then a second photoluminescence detection was performed on the thin-film detection electrode to determine its emission peak intensity PL at a wavelength of 523 nm. 523 Fe ; Add ascorbic acid to the second portion of the first test sample solution and dissolve it; The thin-film detection electrode was immersed in a first sample solution containing ascorbic acid (AA), and then a third photoluminescence detection was performed on the thin-film detection electrode to determine the emission peak intensity PL at a wavelength of 523 nm. 523 AA ; In PL 523 Fe <PL 523 0 And PL 523 Fe <PL 523 AA In this case, it was determined that the first test sample solution contained Fe(III).

2. The detection method according to claim 1, characterized in that, In PL 523 Fe <PL 523 0 And PL 523 Fe <PL 523 AA In the case of [unclear context], the method further includes: preparing a third portion of the first test sample solution, adding dopamine to the third portion of the first test sample solution and dissolving it; immersing the thin-film detection electrode in the first test sample solution containing dopamine (DA), and then performing a fourth photoluminescence detection on the thin-film detection electrode, and determining the emission peak intensity PL at a wavelength of 523 nm. 523 DA ; In PL 523 Fe >PL 523 DA In this case, it was determined that the first test sample solution contained Fe(III).

3. A method for detecting Fe(III), characterized in that, include: Prepare a thin-film detection electrode, which includes a conductive substrate electrode and a CsPbBr3@SiO2 thin film fixed on the surface of the conductive substrate electrode. Prepare two first test sample solutions and a first blank control solution without Fe(III). The thin-film detection electrode was immersed in the first blank control solution, and then the thin-film detection electrode was subjected to the first photoluminescence detection to determine its emission peak intensity L at a wavelength of 523 nm. 523 0 ; The thin-film detection electrode was immersed in the first sample solution, and then a second photoluminescence detection was performed on the thin-film detection electrode to determine its emission peak intensity PL at a wavelength of 523 nm. 523 Fe ; Add dopamine to the second portion of the first test sample solution and dissolve it; The thin-film detection electrode was immersed in a first sample solution containing dopamine, and then a third photoluminescence detection was performed on the thin-film detection electrode to determine the emission peak intensity PL at a wavelength of 523 nm. 523 DA ; In PL 523 0 >PL 523 Fe >PL 523 DA In this case, it was determined that the first test sample solution contained Fe(III).

4. The detection method according to claim 3, characterized in that, PL 523 0 >PL 523 Fe >PL 523 DA In the case of: Prepare a third portion of the first test sample solution, and add ascorbic acid to the third portion of the first test sample solution and dissolve it; The thin-film detection electrode was immersed in a first sample solution containing ascorbic acid, and then a fourth photoluminescence detection was performed on the thin-film detection electrode to determine the emission peak intensity PL at a wavelength of 523 nm. 523 AA ; In PL 523 Fe <PL 523 AA In this case, it was determined that the first test sample solution contained Fe(III).

5. The detection method according to any one of claims 1-4, characterized in that, In the first test sample solution containing ascorbic acid, the concentration of ascorbic acid is below 0.2 mM.

6. The detection method according to any one of claims 1-4, characterized in that, In the first test sample solution containing dopamine, the concentration of dopamine was below 0.4 mM.

7. The detection method according to any one of claims 1-4, characterized in that, The first sample solution to be tested is a weakly acidic buffer solution.

8. A method for detecting dopamine, used to detect dopamine at a concentration less than or equal to 1 μM, characterized in that, Includes the following steps: Prepare a thin-film detection electrode, which includes a conductive substrate electrode and a CsPbBr3@SiO2 thin film fixed on the surface of the conductive substrate electrode. Prepare two test sample solutions containing 2-(dibutylamino)ethanol (DBAE) and a blank control solution containing DBAE but without dopamine. The thin-film detection electrode was immersed in the second blank control solution, and then the thin-film detection electrode was subjected to a first electrochemiluminescence (ECL) detection to determine its electrochemiluminescence intensity (ECL). 0 ; The thin-film detection electrode is immersed in the first portion of the second sample solution, and then a second electrochemiluminescence detection is performed on the thin-film detection electrode to determine its electrochemiluminescence intensity (ECL). DA ; This will cause the second sample solution to contain Fe(III); The thin-film detection electrode was immersed in a second sample solution containing Fe(III), and then a third electrochemiluminescence detection was performed on the thin-film detection electrode to determine its electrochemiluminescence intensity (ECL). Fe ; In ECL DA <ECL 0 And ECL DA <ECL Fe In the case of dopamine, it is determined that the second test sample solution contains dopamine, and the concentration of dopamine is less than or equal to 1 μM.

9. The detection method according to claim 8, characterized in that, In the second test sample solution containing Fe(III), the concentration of Fe(III) was 0.2-0.8 mM.

10. The detection method according to claim 8 or 9, characterized in that, The second sample solution to be tested is a weakly acidic buffer solution.

11. The detection method according to any one of claims 1, 3, and 8, characterized in that, The thin-film detection electrode is prepared by the following method: Preparation of CsPbBr3@SiO2 aqueous dispersion system The CsPbBr3@SiO2 aqueous dispersion was coated onto the surface of the conductive substrate electrode and dried to obtain the thin film detection electrode.

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