Preparation method of high-entropy oxide material and application thereof in electrochemiluminescence detection of levofloxacin
By preparing and modifying a high-entropy oxide HEO-800 electrode, and combining it with the electrochemiluminescence reaction of luminol and oxygen, the problem of insufficient sensitivity in the electrochemiluminescence detection of levofloxacin was solved, achieving high sensitivity and stable detection results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY
- Filing Date
- 2026-02-25
- Publication Date
- 2026-05-29
AI Technical Summary
Existing electrochemiluminescence detection methods for levofloxacin (LVX) lack sufficient sensitivity, making it difficult to achieve efficient and stable detection.
The electrode was modified with a high-entropy oxide HEO-800. The five-element high-entropy oxide material HEO-800 was synthesized by using metal nitrates of Fe, Co, Cu, Zn and Ni as raw materials with Na2CO3 and NaOH. The material was then modified onto a glassy carbon electrode. Electrochemiluminescence detection was performed by combining the electrochemiluminescence reaction of luminol and oxygen.
Highly sensitive electrochemiluminescence detection was achieved, with a linear calibration curve correlation coefficient of 0.993 and a detection limit of 1.02×10-5 μM. It exhibits good stability and reproducibility and is suitable for electrochemiluminescence detection of levofloxacin.
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Figure CN122102224A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electroluminescence technology, specifically relating to a method for preparing a high-entropy oxide HEO-800 modified electrode and its application in electrochemiluminescence detection of levofloxacin (LVX). Background Technology
[0002] Levofloxacin (LVX) is a third-generation quinolone broad-spectrum antibiotic, the levorotatory isomer of ofloxacin. Its core mechanism of action is to inhibit bacterial DNA gyrase and topoisomerase IV, blocking bacterial DNA replication and transcription, thus exerting potent antibacterial activity. This drug has good inhibitory effects on Gram-negative bacteria (such as Escherichia coli and Klebsiella pneumoniae) and some Gram-positive bacteria (such as Staphylococcus aureus). It also features rapid oral absorption, high bioavailability, and strong tissue penetration, and is widely used clinically for the treatment of infections in multiple sites, including the respiratory tract, urinary tract, and digestive tract. Compared to previous generations of quinolones, it has a broader antibacterial spectrum and a lower risk of resistance, making it one of the important drugs for clinical anti-infective therapy. Therefore, establishing a highly sensitive method for detecting LVX is crucial. Currently, methods for LVX determination include fluorescence analysis, colorimetry, flow injection analysis, and electrochemiluminescence (ECL). Among these, ECL has broad application prospects due to its fast response, high reliability, and high sensitivity. Electrochemiluminescence (ECL) combines the advantages of electrochemistry and spectroscopy, generating light signals electrochemically through the redox reaction of a luminescent material. This technology has been widely applied in single-molecule electrochemical reaction imaging, medical diagnostics, environmental monitoring and assessment, immunoassay, and drug analysis. Luminol, with its advantages of being non-toxic and having high luminous efficiency, is one of the most classic and common ECL luminescent materials. To date, most traditional luminol-H₂O₂ ECL systems use H₂O₂ as a classic co-reactant to generate reactive oxygen species (ROS). The ROS react with electrochemically oxidized luminol anions, exhibiting significant anodic emission. This invention utilizes a novel high-entropy oxide, HEO-800, as an effective co-reactant for luminol electroluminescence, establishing a new method for detecting LVX. Summary of the Invention
[0003] The purpose of this invention is to provide a method for preparing a high-entropy oxide HEO-800 modified electrode that is simple to prepare, has readily available raw materials, high catalytic efficiency, and good selectivity, and its application in electrochemiluminescence detection of LVX.
[0004] The technical solution adopted in this invention is:
[0005] A high-entropy oxide material, HEO-800, is a pentagonal high-entropy oxide material synthesized from metal nitrates of Fe, Co, Cu, Zn, and Ni, and Na2CO3 and NaOH as raw materials.
[0006] The preparation method of the above-mentioned high-entropy oxide material includes the following steps: accurately weigh Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Cu(NO3)2·3H2O, Zn(NO3)2·6H2O, and Ni(NO3)2·6H2O solids, dissolve them in deionized water, and stir magnetically; then, dissolve Na2CO3 and NaOH in deionized water in the same way; add the above two solutions to a beaker at the same time and mix them under vigorous stirring; stir the solution for 30 min to obtain a uniform colloidal suspension, transfer the colloidal suspension to a high-pressure reactor, heat and react in an oven, centrifuge, wash, and dry to obtain HE-LDH precursor; then calcine the HE-LDH precursor to obtain a defect-rich high-entropy oxide HEO-800 gray-black powder.
[0007] Furthermore, in the above preparation method, Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Cu(NO3)2·3H2O, Zn(NO3)2·6H2O, and Ni(NO3)2·6H2O are all dissolved in 40 mL of deionized water at a dosage of 5 mmol, and 3.18 g of Na2CO3 and 2.4 g of NaOH are dissolved in 40 mL of deionized water.
[0008] Furthermore, in the above preparation method, the heating reaction temperature is 80 °C, the reaction time is 48 h, and the mixture is naturally cooled to room temperature after the reaction is completed.
[0009] Furthermore, in the above preparation method, the calcination is carried out at 800 °C in air at a rate of 10 °C / min for 2 h.
[0010] A high-entropy oxide HEO-800 modified electrode is prepared as follows: 5.0 mg of HEO-800 powder is dissolved in 5.0 mL of ethanol and ultrasonically vibrated for 2 h. Then, it is mixed with 1% Nafion ethanol solution at a volume ratio of 1:1 and ultrasonically dispersed for 40 min. 6.0 µL of the mixed solution is uniformly coated on the pre-treated glassy carbon electrode and allowed to dry before use.
[0011] Furthermore, in the aforementioned high-entropy oxide HEO-800 modified electrode, the pretreatment method for the glassy carbon electrode is as follows: the bare glassy carbon electrode is ground and polished to a mirror finish with 3 μm Al2O3 powder, then the electrode is rinsed from the side with distilled water, placed in a bottle containing distilled water and sonicated for 3 minutes, and then rinsed with distilled water again.
[0012] The application of the high-entropy oxide HEO-800 modified electrode described above in electrochemiluminescence detection of LVX.
[0013] Furthermore, the above application method is as follows: The high-entropy oxide HEO-800 modified electrode is used as the working electrode, the counter electrode is a platinum sheet electrode, the reference electrode is an Ag / AgCl electrode, and the electrolyte is a PBS solution of 100 mM luminol at pH=9. Before the test, a constant flow of O2 is introduced for 0.5 h. PBS solution containing 100 mM luminol and LVX solutions of different concentrations are added to the electrolytic cell in sequence. Electrochemical and ECL tests are performed at a scan rate of 50 mV / s within a voltage range of -0.8 to 0 V and under the condition of a 700 V photomultiplier tube. The ECL intensity of different concentrations of LVX is measured.
[0014] Furthermore, in the above application, the preparation method of the 100 mM luminol is as follows: First, prepare 100 mL of 0.1 mol L... -1 NaOH solution: Accurately weigh 0.443 g of luminol powder using an analytical balance and add it to 25 mL of 0.1 mol / L solution. -1 The powder was completely dissolved in NaOH solution by stirring for 30 min, yielding 0.1 mol L. -1 Luminol solution can be used after being stored at 4 ℃ in the dark for 7 days.
[0015] The beneficial effects of this invention are:
[0016] 1. This invention catalyzes reactions by modifying synthesized catalyst materials onto glassy carbon electrodes. The raw materials are simple and readily available, and the synthesis operation is easy. Before ECL measurement, a constant flow of O2 is passed through the electrolyte solution for 0.5 h to achieve a saturated oxygen atmosphere, which improves the efficiency of the electrocatalytic reaction.
[0017] 2. The catalyst material synthesized in this invention is used for the electrochemiluminescence detection of levofloxacin. By fitting the change of ECL intensity with LVX concentration, a linear calibration curve was obtained with a correlation coefficient of 0.993 and a detection limit of 1.02 × 10⁻⁶. -5 μM (S / N=3).
[0018] 3. The ECL luminescence intensity of the catalyst material synthesized in this invention is very stable when continuously scanned in a PBS solution containing 100 mM luminol (pH=9) within a potential range of -0.8 V to 0 V. The calculated relative standard deviation (RSD) is 4.3%, indicating that the system has good ECL stability and reproducibility. The HEO-800 catalyst obtained in this invention has good application prospects in the field of electrochemiluminescence detection of levofloxacin. Attached Figure Description
[0019] Figure 1 This is a SEM characterization image of the high-entropy oxide HEO-800 powder prepared in Example 1.
[0020] Figure 2 This is an EDS characterization diagram of the high-entropy oxide HEO-800 powder prepared in Example 1.
[0021] Figure 3 This is the XRD pattern of the high-entropy oxide HEO-800 powder prepared in Example 1.
[0022] Figure 4 It is the high-entropy oxide HEO-800 modified electrode in Example 2. C dl picture.
[0023] Figure 5 This is the EIS image of the high-entropy oxide HEO-800 modified electrode in Example 2.
[0024] Figure 6 The image shows the stability curve of the high-entropy oxide HEO-800 luminol electrochemiluminescence system in Example 2.
[0025] Figure 7 This is a comparison chart of the ECL intensity of the high-entropy oxide HEO-800 / GCE in LVX solutions of different concentrations in Example 2.
[0026] Figure 8 In Example 2, ΔI and lgC LVX The linear logarithmic plot (ΔI=I0-I, where I0 and I are the ECL intensities when LVX is absent and present, respectively). Detailed Implementation
[0027] Example 1: Preparation of a high-entropy oxide HEO-800 modified electrode
[0028] (a) The preparation method is as follows:
[0029] 1) Pretreatment of glassy carbon electrode: The bare glassy carbon electrode was ground and polished to a mirror finish using 3 μm Al2O3 powder. Then, the electrode was rinsed from the side with distilled water, placed in a bottle containing distilled water, and sonicated for 3 min. It was then removed and rinsed again with distilled water. The surface was dried with nitrogen gas, and then CV was performed in 15 mL of 1 mmol / L potassium ferricyanide solution at a scan rate of 0.03 V / s. A potential difference (ΔEp) between the oxidation peak and the reduction peak was considered acceptable, indicating good electrode cleanliness. After rinsing with water and drying with nitrogen gas, it was ready for use. If it did not meet the requirements, it was repolished and characterized using CV until the acceptable potential difference was achieved.
[0030] 2) Preparation of high-entropy oxide HEO-800: Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Cu(NO3)2·3H2O, Zn(NO3)2·6H2O, and Ni(NO3)2·6H2O were dissolved in 40 mL of deionized water at a concentration of 5 mmol each, and the solution was magnetically stirred for 5 min. Then, 3.18 g of Na2CO3 and 2.4 g of NaOH were also dissolved in 40 mL of deionized water. Both solutions were added to a beaker simultaneously and mixed under vigorous stirring. The solution was then magnetically stirred for 30 min to obtain a homogeneous colloidal suspension. The colloidal suspension was transferred to a 100 mL high-pressure reactor lined with stainless steel and polytetrafluoroethylene, and the reaction was carried out in an oven at 80 °C for 48 h. After hydrothermal treatment, the high-pressure reactor was cooled to room temperature. Finally, the precipitate was collected from the resulting solution by centrifugation and washing three times with deionized water, and dried at 60 °C for 12 h. The obtained sample was named high-entropy layered double hydroxide (HE-LDH) precursor. The obtained HE-LDH precursor was calcined at 800 °C in air at a rate of 10 °C / min for 2 h to obtain a defect-rich high-entropy oxide HEO-800 gray-black powder.
[0031] 3) Preparation of HEO-800 modified electrode: 5.0 mg of HEO-800 powder was dissolved in 5.0 mL of ethanol and sonicated for 2 h. Then, it was mixed with 1% Nafion ethanol solution at a volume ratio of 1:1 and sonicated for 40 min to uniformly disperse the solution. 6.0 µL of the mixed solution was uniformly coated onto the pre-treated glassy carbon electrode and allowed to dry before use.
[0032] (II) Test Results
[0033] Figure 1 The image shows a scanning electron microscope (SEM) image of the HEO-800 powder prepared in Example 1. The porous matrix provides structural porosity, while the well-dispersed elongated precipitates ensure phase purity and crystallinity, resulting in a good overall synthesis effect. Figure 2 This is an EDS elemental mapping diagram of the HEO-800 powder prepared in Example 1. The Fe, Co, Cu, Zn and Ni elements are evenly distributed in the diagram, showing good dispersibility, which is beneficial for the full exposure of active sites. Figure 3 The image shows the XRD pattern of HEO-800 powder prepared in Example 1. As the temperature increases from 600 °C to 800 °C, the crystallinity of the material gradually increases, with the optimal crystallinity at 800 °C. However, the crystallinity decreases at 900 °C, which may be accompanied by the formation of secondary phases or structural deterioration.
[0034] Example 2: Application of high-entropy oxide HEO-800 modified electrode in electrochemiluminescence detection of LVX
[0035] Test method: The prepared HEO-800 modified glassy carbon electrode (HEO-800 / GCE) was used as the working electrode.
[0036] Electrochemically active specific surface area (ECSA) is an important factor affecting catalyst performance. ECSA is measured using electrochemical double-layer capacitance (…). C dl It is determined by the slope of a linear fit between the current density and the scan rate. For example... Figure 4 As shown, HE-LDH, HEO-600, HEO-700, HEO-800, and HEO-900... C dl The values were 0.01, 0.09, 0.24, 0.30, and 0.23 mF / cm, respectively. -2 This indicates that the HEO-800 modified electrode has a large exposed surface area in the electrolyte, which helps to promote electron transport on the catalyst surface. The charge transfer capability of HEO-800 was investigated by electrochemical impedance spectroscopy (EIS). Figure 5 In this context, the smaller the semicircular arc, the smaller the charge transfer resistance and the stronger the charge transfer capability.
[0037] Stability testing such as Figure 6 As shown, the ECL intensity of the PBS solution containing 100 mM luminol (pH=9) was very stable during continuous scanning in the potential range of -0.8 V to 0 V. The calculated relative standard deviation (RSD) was 4.3%, indicating that the system has good ECL stability and reproducibility.
[0038] To investigate the ECL intensity at different concentrations of LVX, a luminol solution was first prepared. 100 mL of 0.1 mol / L luminol solution was prepared. -1 NaOH solution: Accurately weigh 0.443 g of luminol powder using an analytical balance and add it to 25 mL of 0.1 mol / L solution. -1 The powder was completely dissolved in NaOH solution by stirring for 30 min, yielding 0.1 mol L. -1 The luminol solution was ready for use after 7 days of storage at 4 °C in the dark. A high-entropy oxide HEO-800 modified electrode was used as the working electrode, a platinum sheet electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was a PBS solution of 100 mM luminol at pH 9. A constant flow of O2 was introduced for 0.5 h before testing. PBS solution containing 100 mM luminol and different concentrations of LVX solution were added sequentially to the electrolytic cell. Electrochemical and ECL tests were performed at a scan rate of 50 mV / s within a voltage range of -0.8 to 0 V and under 700 V photomultiplier tube conditions. Figure 7 and Figure 8 It can be seen that the change in ECL intensity on HEO-800 / GCE with the change in LVX concentration can be expressed by the equation ΔI=707.8 logC. LVX +3473.5 Description (ΔI = I0 - I, where I0 and I are the ECL intensities in the absence and presence of LVX, respectively). ECL intensity decreases monotonically with increasing LVX concentration, and the correlation coefficient (R) 2 The correlation coefficient (CLC) was 0.993, indicating a very strong linear correlation between ECL intensity and LVX concentration. Furthermore, the limit of detection (LOD) for LVX was 1.02 × 10⁻⁶. -5 μM, which is the lowest concentration measured at a signal-to-noise ratio (S / N) of 3.
[0039] In summary, the high-entropy oxide HEO-800 modified electrode of this invention exhibits good sensitivity, selectivity, stability, and reproducibility, as well as excellent electrochemiluminescence performance. It shows promising potential for development in the field of electrochemiluminescence detection of levofloxacin.
Claims
1. A high-entropy oxide material, characterized in that, HEO-800 is a five-element high-entropy oxide material synthesized from metal nitrates of Fe, Co, Cu, Zn, and Ni, and Na2CO3 and NaOH as raw materials.
2. The method for preparing a high-entropy oxide material according to claim 1, characterized in that, The process includes the following steps: accurately weigh the solids Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Cu(NO3)2·3H2O, Zn(NO3)2·6H2O, and Ni(NO3)2·6H2O, dissolve them in deionized water, and stir magnetically; then, dissolve Na2CO3 and NaOH in deionized water in the same way. Both solutions were added to a beaker simultaneously and mixed under vigorous stirring. The solution was stirred for 30 min to obtain a uniform colloidal suspension. The colloidal suspension was transferred to a high-pressure reactor and heated in an oven. After centrifugation, washing, and drying, the HE-LDH precursor was obtained. Subsequently, the HE-LDH precursor was calcined to obtain a defect-rich high-entropy oxide, HEO-800, in gray-black powder.
3. The preparation method according to claim 2, characterized in that, Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Cu(NO3)2·3H2O, Zn(NO3)2·6H2O, and Ni(NO3)2·6H2O were all dissolved in 40 mL of deionized water at a dosage of 5 mmol. 3.18 g of Na2CO3 and 2.4 g of NaOH were also dissolved in 40 mL of deionized water.
4. The preparation method according to claim 2, characterized in that, The heating reaction temperature was 80 °C, the reaction time was 48 h, and the mixture was allowed to cool naturally to room temperature after the reaction was completed.
5. The preparation method according to claim 2, characterized in that, The calcination was carried out at 800 °C in air at a rate of 10 °C / min for 2 h.
6. A high-entropy oxide HEO-800 modified electrode, characterized in that, The preparation method is as follows: 5.0 mg HEO-800 powder is dissolved in 5.0 mL of ethanol and ultrasonically vibrated for 2 h. Then it is mixed with 1% Nafion ethanol solution at a volume ratio of 1:1 and ultrasonically vibrated for 40 min to uniformly disperse the solution. 6.0 µL of the mixed solution is uniformly coated on the treated glassy carbon electrode and left to dry before use.
7. The high-entropy oxide HEO-800 modified electrode according to claim 6, characterized in that, The pretreatment method for the glassy carbon electrode is as follows: the bare glassy carbon electrode is ground and polished to a mirror finish with 3 μm Al2O3 powder, then the electrode is rinsed from the side with distilled water, placed in a bottle with distilled water and sonicated for 3 minutes, and then rinsed with distilled water again.
8. The application of the high-entropy oxide HEO-800 modified electrode as described in claim 6 or 7 in electrochemiluminescence detection of LVX.
9. The application according to claim 8, characterized in that, The application method is as follows: The high-entropy oxide HEO-800 modified electrode is used as the working electrode, the counter electrode is a platinum sheet electrode, the reference electrode is an Ag / AgCl electrode, and the electrolyte is a PBS solution of 100 mM luminol at pH=9. Before the test, a constant flow of O2 is introduced for 0.5 h. PBS solution containing 100 mM luminol and LVX solutions of different concentrations are added to the electrolytic cell in sequence. Electrochemical and ECL tests are performed at a scan rate of 50 mV / s under the conditions of a 700 V photomultiplier tube within a voltage range of -0.8 to 0 V, and the ECL intensity is measured at different concentrations of LVX.
10. The application according to claim 9, characterized in that, The preparation method of the 100 mM luminol is as follows: First, prepare 100 mL of 0.1 mol L... -1 NaOH solution: Accurately weigh 0.443 g of luminol powder using an analytical balance and add it to 25 mL of 0.1 mol / L solution. -1 The powder was completely dissolved in NaOH solution by stirring for 30 min, yielding 0.1 mol L. -1 Luminol solution can be used after being stored at 4°C in the dark for 7 days.