A lumi-nol low potential electrochemiluminescence method based on SnSe-mediated water activation

Abstract

The application discloses a luminol low-potential electrochemiluminescence (ECL) method based on SnSe-mediated water activation. The method breaks through the limitations of high trigger potential and unstable signal in the traditional luminol-water ECL system. Sn vacancies induce the continuous dissociation of H2O and the activation of O2 molecules, in-situ generate H2O2 under mild conditions without additional energy input, and further convert into active oxygen species (ROS) as water-derived co-reactants to participate in the luminol ECL reaction. This strategy places the water activation process before the electrochemical oxidation of luminol, making the system no longer rely on high potential water oxidation to produce active substances, but only need to reach the oxidation potential of luminol to trigger stable ECL emission. It can effectively reduce the O2 bubble accumulation, side reaction interference and signal fluctuation caused by high potential water oxidation, and provides a new method for constructing a luminol-water ECL system with low trigger potential, stability and simple composition.

Description

Technical Field

[0001] This invention belongs to the field of electrochemiluminescence detection technology and discloses a low-potential electrochemiluminescence method for luminol based on SnSe-mediated water activation. Specifically, it involves the preparation of SnVSe and the successful realization of continuous activation of water molecules under mild conditions using SnVSe material, and the in-situ generation of H2O2 and its derived reactive oxygen species. Stable low-potential electrochemiluminescence signals can be obtained only at the luminol oxidation potential (+0.4 V). Background Technology

[0002] Luminol electrochemiluminescence (ECL) systems have been widely used in analytical detection and biosensing due to their advantages such as low background signal, high sensitivity, and rapid response. Traditional luminol ECL typically relies on the addition of H₂O₂ or dissolved oxygen as co-reactants to generate reactive oxygen species (ROS) and promote luminol oxidation and luminescence. While H₂O₂-mediated systems can achieve high luminescence efficiency, H₂O₂ itself is unstable and prone to self-decomposition, easily leading to increased background signal, uncontrollable reaction process, and decreased signal stability. Dissolved oxygen-mediated systems, while avoiding the problems associated with added H₂O₂, suffer from low solubility of O₂ in aqueous solutions, and its supply process is affected by diffusion, atmosphere, and local consumption, easily resulting in insufficient co-reactant supply and poor ECL signal repeatability. Therefore, developing novel luminol ECL systems that do not require the addition of unstable co-reactants and can stably provide active substances is of great significance.

[0003] In recent years, the luminol-water ECL system has attracted attention due to its ability to use water as a co-reactant precursor, avoiding the inherent defects of traditional H2O2 and dissolved oxygen-mediated systems. In contrast, water, as the main solvent, is abundant, has a stable concentration, and requires no additional strong oxidizing agents, thus offering the possibility of constructing a low-background, simple-composition luminol ECL system. However, due to the stable structure of water molecules, direct electrochemical activation of water typically requires a high trigger potential. At high potentials, water oxidation side reactions are enhanced, and O2 bubbles easily form and accumulate on the electrode surface, thus obscuring the effective electrode area, hindering interfacial mass transfer, and disrupting the local reaction environment, ultimately leading to unstable ECL signals. Furthermore, high potentials may induce non-specific oxidation reactions and reduce the system's biocompatibility. Therefore, achieving efficient water activation at lower potentials while reducing bubble accumulation and side reaction interference is crucial for the further development of the luminol-water ECL system.

[0004] Traditional luminol ECL systems mediated by H2O2 or dissolved oxygen suffer from limitations such as poor stability of co-reactants and insufficient supply. Current luminol-water ECL systems typically rely on high-potential water electrolysis to generate active substances, which easily leads to O2 bubble accumulation, side reaction interference, and signal instability. Based on the above analysis, this invention aims to develop a novel low-potential luminol-water ECL method based on Sn vacancy-mediated water activation, achieving stable ECL signal output with a low trigger potential. Summary of the Invention

[0005] To address the issues of insufficient ECL signal stability caused by the high trigger potential required for water activation, easy O2 bubble accumulation, and side reaction interference in the current luminol-water ECL system, and to simultaneously reduce the possibility of non-specific oxidation of electroactive interfering substances at high potentials, thereby improving detection selectivity, this invention employs the following technical solution:

[0006] This invention first discloses a low-potential electrochemiluminescence method for luminol based on SnSe-mediated water activation, comprising:

[0007] Sn V Se catalytic material is loaded onto the surface of the working electrode, and in a luminol-containing buffer electrolyte, the Sn catalytic material is utilized. V Se-catalyst-mediated water activation reaction generates ROS in situ, which acts as a co-reactant to trigger luminol to generate an ECL signal at low potential.

[0008] Furthermore, the detection employs a standard three-electrode system, with Sn... V The Se-modified electrode is the working electrode, the platinum electrode is the counter electrode, and the Ag / AgCl electrode is the reference electrode.

[0009] Furthermore, the electrolyte is a 0.1 M Britton-Robinson buffer solution containing 0.12 mM luminol, pH = 10; the photomultiplier tube voltage is 600 V.

[0010] Furthermore, the Sn V Se catalysts are prepared by the following steps:

[0011] (1) Dissolve 47.4 mg of stannous chloride in 20 mL of oleylamine and sonicate for 2 min. Then, degas the solution and purge it under a nitrogen atmosphere for 1 h to remove dissolved oxygen and obtain a tin precursor solution.

[0012] (2) Heat the tin precursor solution to 240 °C and maintain it for 15 min. Then quickly inject it into HMDS-TOP-Se solution. When the reaction system turns black, continue the reaction for 30 min. After the reaction is completed, cool the system to room temperature, add isopropanol-toluene mixed solvent, and then centrifuge for 10 min to collect the black powder obtained.

[0013] (3) The obtained black powder was washed three times with a mixed solvent of isopropanol and ethanol, centrifuged for 5 min each time. Finally, the product was dried in a vacuum oven at 60 °C for 12 h to obtain Sn. V Se catalytic materials.

[0014] Further, the HMDS-TOP-Se solution in step (2) is prepared by the following method:

[0015] ① Dissolve 0.395 g of selenium powder in 5 mL of trioctylphosphine to prepare a TOP-Se precursor solution;

[0016] ② Mix 0.25 mL of TOP-Se solution with 1 mL of hexamethyldisilazane to obtain HMDS-TOP-Se solution.

[0017] Further, the isopropanol-toluene mixed solvent in step (2) consists of 40 mL of isopropanol and 8 mL of toluene.

[0018] Further, the isopropanol-ethanol mixed solvent in step (3) is prepared by mixing isopropanol and ethanol in a volume ratio of 2:1.

[0019] The beneficial effects of this invention are as follows:

[0020] Unlike the method of generating active substances by directly electrolyzing water at high potential, Sn V Se can utilize Sn vacancy defects to induce continuous dissociation of H2O and activation of O2 molecules, generating H2O2 in situ under mild conditions without additional energy input. This H2O2 is further converted into ROS, which participates in the luminol ECL reaction as a water-derived, self-supplied co-reactant. This strategy places the water activation process before the electrochemical oxidation of luminol, eliminating the system's reliance on high-potential water oxidation to generate active substances. Stable ECL luminescence can be triggered simply by reaching the oxidation potential of luminol (+0.4 V), significantly improving the problems of high trigger potential and poor signal stability in traditional luminol-water ECL systems. Experiments demonstrate that Sn... VThe Se-mediated luminol-water ECL system can achieve stable signal output at low potentials, effectively reducing O2 bubble accumulation, side reaction interference, and signal fluctuations caused by high-potential water oxidation, thereby improving the system's selectivity and anti-interference ability in the detection of complex samples. This provides a new method for constructing a low-trigger-potential, stable, and simple luminol-water ECL system. Attached Figure Description

[0021] Figure 1 For Sn V Flowchart of Se catalytic material preparation.

[0022] Figure 2 For Sn V (a) Transmission electron microscope image and (b) X-ray diffraction pattern of Se catalytic material.

[0023] Figure 3 In the diagram, (a) represents GCE and Sn. V (a) CV curve of Se in 0.1 M BR buffer (pH = 10) containing 0.12 mM luminol; (b) GCE and Sn in the same system. V Comparison of ECL trigger potential and intensity of Se.

[0024] Figure 4 ECL potential-intensity plot of GCE in 0.1 M BR buffer (pH = 10) containing 0.12 mM luminol, 0.2–1.3 V.

[0025] Figure 5 In the image, (a) shows a comparison of ECL intensities at different luminol concentrations; (b) shows a comparison of different Sn concentrations. V Comparison of ECL intensity with Se concentration.

[0026] Figure 6 Comparison of UV absorption spectra of the HRP + TMB system (blue line is the control without H2O2, red line is the control with Sn). V Following the Se-water reaction product, an absorption peak is observed after the oxidation of TMB.

[0027] Figure 7 To compare the presence or absence of Sn under conditions of 0.2-0.6 V. V The response of the water interface to the Se catalytic material was measured using in-situ diffuse reflectance infrared Fourier transform spectra (where the blue line indicates the presence of Sn). V Se, the red line indicates no Sn. V Se). Detailed Implementation

[0028] Example 1

[0029] Preparation of Sn based on Sn vacancyV Se catalytic materials

[0030] See attached document Figure 1 As shown, Sn with Sn vacancies was prepared by the hot injection method. V Se catalytic materials.

[0031] 0.395 g of selenium powder (Se powder) was dissolved in 5 mL of trioctylphosphine (TOP) to prepare a TOP-Se precursor solution. Then, 0.25 mL of the TOP-Se solution was mixed with 1 mL of hexamethyldisilazane (HMDS) to obtain an HMDS-TOP-Se solution. Simultaneously, 47.4 mg of stannous chloride (SnCl2) was dissolved in 20 mL of oleylamine and sonicated for 2 min to form a tin precursor solution. This tin precursor solution was then degassed and purged under a nitrogen atmosphere for 1 h to remove dissolved oxygen. The tin precursor solution was then heated to 240 °C and held for 15 min, followed by rapid injection of the HMDS-TOP-Se solution. The reaction was continued for 30 min after the system turned black. After the reaction was complete, the system was cooled to room temperature, and a mixture of 40 mL of isopropanol and 8 mL of toluene was added. The mixture was then centrifuged for 10 min, and the resulting black powder was collected. The resulting powder was then washed three times with a mixture of isopropanol / ethanol (volume ratio 2:1), centrifuged for 5 min each time. Finally, the product was dried in a vacuum oven at 60 °C for 12 h to obtain Sn. V Se.

[0032] Sn prepared in Example 1 V The Se catalytic material was observed using transmission electron microscopy, and the results are as follows: Figure 2 As shown: Sn V Se exhibits a nanosheet morphology. The X-ray diffraction pattern is in good agreement with the orthorhombic Pnma crystal structure of pure SnSe (PDF#48-1224), and no obvious impurity phases were detected.

[0033] Sn prepared in Example 1 V ECL analysis was performed on the Se catalyst, and the results are as follows: Figure 3 As shown: On bare GCE, the onset oxidation potential of luminol is approximately 0.38 V, with the oxidation peak located at approximately 0.45 V. In contrast, Sn... V The Se-modified electrode exhibits a sustained increase in anolyte current at approximately 0.2 V, indicating that this current response is not solely derived from luminol oxidation but may also include Sn. V Se-mediated water activation processes and related ROS generation reactions. Furthermore, Sn... VAfter Se modification, the ECL onset potential was slightly advanced from approximately 0.42 V in the bare GCE to approximately 0.4 V, which is basically consistent with the onset oxidation potential of luminol, indicating that the luminescence of this system is mainly triggered by luminol oxidation. At the same time, H2O2 generated in situ at the interface participates in the reaction as a self-supplied co-reactant, thereby increasing the ECL intensity to 16.9 times that of the bare GCE (peak intensity ratio).

[0034] Example 2

[0035] Sn V Se-mediated luminol-electrochemiluminescence low-potential detection

[0036] (1) Sn V Preparation of Se-modified working electrode

[0037] Sn V Se catalyst material was dispersed in anhydrous ethanol to prepare a homogeneous suspension (slurry) with a concentration of 2 mg / mL. A clean glassy carbon electrode (GCE, 3 mm in diameter) was polished to a mirror finish on chamois leather using 0.3 μm and 0.05 μm alumina polishing powders, respectively. It was then ultrasonically cleaned with anhydrous ethanol and deionized water for 3 minutes each, and dried under nitrogen. 10 μL of the above Sn catalyst was accurately pipetted using a micropipette. V Se slurry was drop-coated onto the treated GCE surface and allowed to dry naturally at room temperature to obtain Sn. V Se-modified electrode (Sn) V Se / GCE).

[0038] (2) Preparation of electrolyte

[0039] Weigh an appropriate amount of luminol, dissolve and dilute it with 0.1 M Britton-Robinson (BR) buffer solution to prepare an electrolyte containing 0.12 mM luminol, and adjust the pH to 10.0 with 0.1 M NaOH or H3PO4.

[0040] (3) Electrochemiluminescence test

[0041] ECL testing was performed in a standard three-electrode system: Sn prepared in step (1) V Se / GCE was used as the working electrode, a platinum sheet (1 cm × 1 cm) as the counter electrode, and an Ag / AgCl (saturated KCl) electrode as the reference electrode. The three electrodes were placed in the BR buffer electrolyte (pH = 10) containing 0.12 mM luminol, and the photomultiplier tube (PMT) voltage was set to 600 V. Cyclic voltammetry was used for testing, with a scan potential range of +0.2 ~ +0.6 V and a scan rate of 100 mV / s.

[0042] (4) Results

[0043] Test results show that a stable and strong ECL luminescence signal can be observed near +0.4 V (vs. Ag / AgCl). Compared to the traditional luminol-water system, which requires around 1.2 V to trigger, this embodiment reduces the trigger potential by approximately 75%, and after 10 consecutive scans, the ECL signal intensity retention rate is greater than 95%, indicating that Sn... V Se-mediated water activation strategy can achieve stable output of luminol ECL at low potentials, effectively suppressing O2 bubble accumulation and side reaction interference at high potentials.

[0044] Comparative Example 1

[0045] luminol-electrochemiluminescence detection of naked GCE

[0046] Using the exact same electrolyte and test conditions as in Example 2, except that the working electrode was replaced with unmodified bare GCE, it was demonstrated that Sn-free... V The ECL signal is only triggered when Se is around +1.2 V (e.g., Figure 4 (As shown).

[0047] Experimental Example 1

[0048] Effects of different luminol concentrations on low potential ECL signals

[0049] SnVSe / GCE modified electrodes and three-electrode systems were prepared using the same method as in Example 2. 0.1 M BR buffer solutions (pH = 10) containing 0.08 mM, 0.12 mM, and 0.16 mM luminol were prepared, and ECL tests were performed under the same test conditions (PMT voltage 600 V, scan rate 100 mV / s).

[0050] The results showed that as the luminol concentration increased from 0.08 mM to 0.12 mM, the ECL signal intensity increased significantly from 6894 to 11313; when the concentration continued to increase to 0.16 mM, the signal intensity was 14011, and the signal increase tended to slow down (e.g., Figure 5 (as shown in a). Therefore, considering luminescence intensity, response efficiency, and reagent consumption, 0.12 mM was selected as the optimal luminol concentration for subsequent experiments.

[0051] Experimental Example 2

[0052] Different Sn V Effect of Se loading on the performance of modified electrode ECL

[0053] Sn was prepared at concentrations of 1 mg / mL, 2 mg / mL and 3 mg / mL respectively. VSe homogenate was used, and 10 μL of each was dropped onto the polished GCE surface to prepare modified electrodes with different loadings. ECL tests were performed according to the electrolyte composition (0.12 mM luminol, 0.1 M BR, pH = 10) and test conditions of Example 2.

[0054] The results showed that at a loading of 1 mg / mL, the ECL signal was weak and unstable, with a value of only 8193; at a loading of 2 mg / mL, the signal strength and stability reached the optimal balance (11313); at a loading of 3 mg / mL, the signal strength did not improve significantly, but instead decreased to 4682, and the excessively thick film layer on the electrode surface led to a slight increase in background noise (e.g., Figure 5 (as shown in b). Therefore, 2 mg / mL is the optimal catalyst loading concentration.

[0055] Experimental Example 3

[0056] Catalytic water activation test

[0057] During the catalytic reaction, 1 mg of Sn V Se catalyst was uniformly dispersed in 20 mL of deionized water. After reacting for 10 min, the mixture was filtered through a 0.22 μm microporous membrane to remove unreacted catalyst particles. Then, 100 μL of the filtrate was added to the colorimetric reaction system, followed by the addition of 10 μL of HRP solution (0.01 mg / mL). -1 100 μL of TMB solution (1 mM) and 100 μL of NaAc-HAc buffer (pH = 3.5) were mixed thoroughly, and the generation of H2O2 during the reaction was verified by measuring the change in absorbance at 652 nm. (See attached...) Figure 6 As shown, at a wavelength of 652 nm, the HRP + TMB system exhibits almost no absorption in the absence of H2O2 (blue line). However, the addition of Sn... V After the product of the reaction between Se and water, a clear absorption peak (red line) appears in the solution, indicating that TMB is oxidized to generate a blue product, which indirectly proves that SnVSe can effectively catalyze the generation of H2O2 from water under mild conditions.

[0058] Test Example 4

[0059] Water activation mechanism research and verification experiment

[0060] See attached document Figure 7 As shown, in-situ diffuse reflectance infrared Fourier transform spectroscopy was used to identify key active intermediates involved in the reaction process. Located at 2873 cm⁻¹ -1 The peak can be attributed to OH bond vibration, and its intensity gradually increases with reaction time, indicating the formation of new peroxide-related OH species in the system. Meanwhile, the peak with *OOH (1106 cm⁻¹)-1 ) and •O2 - (1225 cm) -1 The simultaneous enhancement of the related absorption peaks indicates that O2 was effectively activated during the reaction. Furthermore, the *OH (3468 cm⁻¹) -1 The appearance of the vibration peak indicates that water molecules undergo adsorption and dissociation on the catalyst surface. These results collectively demonstrate that the reaction involves both water molecule dissociation and O2 activation, further supporting the in-situ generation of H2O2.

Claims

1. A low-potential electrochemiluminescence method for luminol based on SnSe-mediated water activation, comprising: Sn V Se catalytic material is loaded onto the surface of the working electrode, and in a luminol-containing buffer electrolyte, the Sn catalytic material is utilized. V Se-catalyst-mediated water activation reaction generates ROS in situ, which serves as a co-reactant to trigger luminol to generate an ECL signal at low potential.

2. The method according to claim 1, wherein: The detection employs a standard three-electrode system, with Sn... V The Se-modified electrode is the working electrode, the platinum electrode is the counter electrode, and the Ag / AgCl electrode is the reference electrode.

3. The method according to claim 1, wherein: The electrolyte is a 0.1 M Britton-Robinson buffer solution containing 0.12 mM luminol, pH = 10; the photomultiplier tube voltage is 600 V.

4. The method according to claim 1, wherein: The Sn V Se catalysts are prepared by the following steps: (1) Dissolve 47.4 mg of stannous chloride in 20 mL of oleylamine and sonicate for 2 min. Then, degas the solution and purge it under a nitrogen atmosphere for 1 h to remove dissolved oxygen and obtain a tin precursor solution. (2) Heat the tin precursor solution to 240 °C and maintain it for 15 min. Then quickly inject it into HMDS-TOP-Se solution. When the reaction system turns black, continue the reaction for 30 min. After the reaction is completed, cool the system to room temperature, add isopropanol-toluene mixed solvent, and then centrifuge for 10 min to collect the black powder obtained. (3) The obtained black powder was washed three times with a mixed solvent of isopropanol and ethanol, centrifuged for 5 min each time. Finally, the product was dried in a vacuum oven at 60 °C for 12 h to obtain Sn. V Se catalytic materials.

5. The method according to claim 4, wherein: The HMDS-TOP-Se solution in step (2) is prepared by the following method: ① Dissolve 0.395 g of selenium powder in 5 mL of trioctylphosphine to prepare a TOP-Se precursor solution; ② Mix 0.25 mL of TOP-Se solution with 1 mL of hexamethyldisilazane to obtain HMDS-TOP-Se solution.

6. The method according to claim 4, wherein: The isopropanol-toluene mixed solvent in step (2) consists of 40 mL of isopropanol and 8 mL of toluene.

7. The method according to claim 4, wherein: The isopropanol-ethanol mixed solvent in step (3) is prepared by mixing isopropanol and ethanol in a volume ratio of 2:1.

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