Preparation method and application of methylthio-modified Ce-MOF electrode material
By preparing methylthio modified Ce-MOF electrode materials, the complex and expensive problems of existing heavy metal ion detection methods are solved, and efficient and sensitive heavy metal ion detection is achieved, especially the detection of Cd2+, Pb2+, Cu2+ and Hg2+, which is suitable for real samples.
Patent Information
- Application Number
- CN202510521431.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-18
- Publication Date
- 2025-08-19
AI Technical Summary
The existing heavy metal ion detection equipment is expensive, complex and time-consuming, and requires the development of an efficient, sensitive and easy-to-preparation electrochemical sensor.
The Ce-MOF electrode material modified with methylthio group is used. The preparation method includes weighing cerium ammonium nitrate and methylthio terephthalic acid dissolved in DMF, reacting to form a yellow solution, and obtaining the methylthio group modified Ce-MOF electrode material by centrifugation, washing and drying, for electrochemical detection.
It realizes low detection limit, wide linear range and high selective detection of heavy metal ions, especially Cd2+, Pb2+, Cu2+ and Hg2+, which is suitable for the detection of real samples.
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Figure CN120504837A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of electrochemical sensing technology, and more specifically to a method for preparing a methylthio-modified Ce-MOF electrode material and its application in electrochemical sensing detection of heavy metal ions. Background Art
[0002] Methods for detecting heavy metal ions include energy dispersive X-ray fluorescence spectrometry, inductively coupled plasma mass spectrometry, and flame atomic absorption spectrometry. However, these techniques are not only expensive in terms of testing equipment, but also complex and time-consuming to operate. Therefore, there is an urgent need for efficient sample preparation and analytical methods to detect heavy metal ions. Various nanomaterial-based sensors have been developed for the detection of metal ions, including fluorescent sensors based on gold nanoparticles, colorimetric sensors based on silver nanoclusters, and electrochemical sensors based on metal-organic frameworks (MOFs). It is worth noting that electrochemical sensors are widely used to detect metal ions due to their sensitivity, efficiency, and ease of preparation. Summary of the Invention
[0003] The purpose of the present invention is to provide a method for preparing a methylthio-modified Ce-MOF electrode material with low electrochemical heavy metal detection limit, wide linear range and good selectivity.
[0004] The present invention employs a method for preparing a methylthio-modified Ce-MOF electrode material, comprising the following steps: weighing ceric ammonium nitrate and methylthioterephthalic acid, dissolving acetic acid in 15 mL of DMF, stirring for 15 minutes, transferring the mixture to a round-bottom flask, and reacting in a 35°C oil bath for 24 hours to form a yellow solution. The product is collected by centrifugation, washed with ethanol and acetone, and finally dried under vacuum to obtain the methylthio-modified Ce-MOF electrode material.
[0005] Furthermore, in the above preparation method, the molar ratio of cerium ammonium nitrate and methylthio terephthalic acid is 1:1.
[0006] Furthermore, the above-mentioned preparation method comprises the following steps: dissolving 2,5-dimercaptoterephthalic acid in acetone, adding K2CO3, adding iodomethane dropwise with stirring, stirring the mixture at room temperature for 1 hour, and then removing excess solvent in vacuo. The resulting residue is dissolved in deionized water and cooled to 0°C. The pH of the solution is then adjusted to 1.5 with 2M hydrochloric acid, and the precipitate is filtered to obtain a yellow solid powder. The precipitate is washed with cold water and air-dried for 24 hours to obtain methylthioterephthalic acid.
[0007] Furthermore, in the above preparation method, the solvent DMF is first dried and dehydrated.
[0008] Furthermore, in the above preparation method, the mixed solution is uniformly dispersed and then reacted in an oil bath at 35° C. for 24 hours.
[0009] Furthermore, in the above preparation method, the mixed solution is heated at 180° C. in a forced air drying oven for 5 days.
[0010] The present invention provides an application of a methylthio-modified Ce-MOF electrode material as an electrochemical electrode sensing material in electrochemical detection of heavy metal ions.
[0011] Furthermore, the method is as follows: 2.0 mg of methylthio-modified Ce-MOF electrode material is dispersed in 1.0 ml of water and sonicated for 30 minutes to form a uniform suspension. Subsequently, 8.0 μL of the suspension is deposited onto the exposed GCE surface and air-dried at room temperature to obtain the sensing working electrode. A platinum wire electrode serves as the counter electrode, and a silver / silver chloride electrode serves as the reference electrode.
[0012] Furthermore, the electrochemical properties of the GCE sensing material were characterized by differential pulse stripping voltammetry (DPSV) in 1 M acetate buffer solution (pH = 5-8) at room temperature. The DPSV measurement was performed under a deposition time of 5s-50s, a pulse width of 0.1s-1s, a potential range of -1.0V-1.4V, an amplitude of 5mV-50mV, and a potential increment of 1mV-5mV.
[0013] The beneficial effects of the present invention are as follows: a methylsulfide-modified Ce-MOF electrode material prepared by the present invention is used to construct a cost-effective, simple and sensitive analytical method for the separate and simultaneous detection of heavy metal ions. When methylsulfide ions form complexes with metal ions, their charge state or electrochemical properties may change. By measuring the change in current or potential, the presence and concentration of metal ions can be determined. In addition, methylsulfide ions can form complexes with some metal ions and easily interact electrostatically with positively charged heavy metal ions. This characteristic makes the electrochemical sensor prepared using this electrode material have the advantages of low detection limit, wide linear range and good selectivity, and can be used for the detection of Cd in real samples. 2 + , Pb 2+ 、Cu 2+ and Hg 2+ For the simultaneous detection of Cd 2+ , Pb 2+ 、Cu 2+ and Hg 2+ Provides a new approach. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 This is an SEM image of the methylthio-modified Ce-MOF electrode material prepared in the present invention;
[0015] Figure 2 The methylthio-modified Ce-MOF electrode material prepared in the present invention was subjected to differential pulse voltammetry on an electrochemical workstation to measure the electrochemical activity of Cd at different concentrations. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ DPV curves of individual ion measurements;
[0016] Figure 3 The methylthio-modified Ce-MOF electrode material prepared in the present invention was subjected to differential pulse voltammetry on an electrochemical workstation to measure the electrochemical activity of Cd at different concentrations. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ Concentration curves of individual ion measurements;
[0017] Figure 4 The methylthio-modified Ce-MOF electrode material prepared in the present invention was subjected to differential pulse voltammetry on an electrochemical workstation to measure the electrochemical activity of Cd at different concentrations. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ DPV curve diagram of simultaneous ion measurement;
[0018] Figure 5 The methylthio-modified Ce-MOF electrode material prepared in the present invention was subjected to differential pulse voltammetry on an electrochemical workstation to measure the electrochemical activity of Cd at different concentrations. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ Concentration curves of ions measured simultaneously; DETAILED DESCRIPTION
[0019] The technical solution of the present invention is further described below through specific embodiments.
[0020] Example 1:
[0021] 1.54 g (10 mmol) of 2,5-dimercaptoterephthalic acid was dissolved in 81 mL of acetone, and 4.14 g of K2CO3 (30 mmol) was added. 685 μL (11 mmol) of iodomethane was added dropwise with stirring. The mixture was stirred at room temperature for 1 hour, after which the excess solvent was removed in vacuo. The resulting residue was dissolved in 40 mL of deionized water and cooled to 0°C. The pH of the solution was then adjusted to 1.5 with 2 M hydrochloric acid, and the precipitate was filtered, washed with cold water, and air-dried for 24 hours to yield 1.61 g of H2B methylthioterephthalic acid as a yellow solid powder.
[0022] 0.25 mmol (146.2 mg) of cerium ammonium nitrate, 0.25 mmol (58.22 mg) of methylthioterephthalic acid, and 1.5 mL of acetic acid were weighed and dissolved in DMF (15 mL). Stirred for 15 minutes, the mixture was transferred to a round-bottom flask and reacted in a 35°C oil bath for 24 hours to form a yellow solution. The product was collected by centrifugation, washed three times with ethanol and acetone, and finally dried under vacuum at 60°C for 48 hours to obtain the methylthio-modified Ce-MOF electrode material as a yellow solid powder.
[0023] Scanning the electrode material in Example 1 using a scanning electron microscope (SEM) revealed that the electrode material was elliptical nanoparticles. Figure 1 shown.
[0024] Example 2:
[0025] 3.08 g (20 mmol) of 2,5-dimercaptoterephthalic acid was dissolved in acetone (81 mL), and 8.28 g of K2CO3 (60 mmol) was added. 1285 μL (22 mmol) of iodomethane was added dropwise with stirring. The mixture was stirred at room temperature for 1 hour, and then the excess solvent was removed in vacuo. The resulting residue was dissolved in 80 mL of deionized water and cooled to 0°C. The pH of the solution was then adjusted to 1.5 with 2 M hydrochloric acid, and the precipitate was filtered, washed with cold water, and air-dried for 24 hours to obtain 3.22 g of H2B methylthioterephthalic acid as a yellow solid powder.
[0026] 0.5 mmol (292.4 mg) of cerium ammonium nitrate and 0.5 mmol (116.44 mg) of methylthioterephthalic acid were weighed and dissolved in 15 mL of DMF. The mixture was stirred for 15 minutes, then transferred to a round-bottom flask and reacted in a 35°C oil bath for 24 hours to form a yellow solution. The product was collected by centrifugation, washed three times with ethanol and acetone, and finally dried under vacuum at 60°C for 48 hours to obtain the methylthio-modified Ce-MOF electrode material as a yellow solid powder.
[0027] Example 3:
[0028] The methylthio-modified Ce-MOF electrode material obtained in Example 1 was used as an electrode sensing material for the electrochemical detection of heavy metal ions. 2.0 mg of the methylthio-modified Ce-MOF was dispersed in 1.0 ml of water and sonicated for 30 minutes to form a uniform suspension. Subsequently, 8.0 μL of the suspension was deposited onto the exposed GCE surface and air-dried at room temperature to obtain the sensing working electrode. A platinum wire electrode served as the counter electrode, and a silver / silver chloride electrode served as the reference electrode.
[0029] Differential pulse stripping voltammetry (DPSV) was used to measure the concentrations of Cd in 1 M acetate buffer (pH = 5) at room temperature. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ The ions were determined individually, and the DPSV measurements were performed with a deposition time of 10 s, a pulse width of 0.2 s, a potential range of -1.0 V to 0.4 V, an amplitude of 50 mV, and a potential increment of 5 mV. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ The DPSV peak current increases with Cd 2+ , Pb 2+ 、Cu 2+ and Hg 2+ The concentration increases linearly ( Figure 2 ), with concentrations ranging from 0.03-5.0 μM, 0.03-11.0 μM, 0.03-10.0 μM and 0.03-5 μM ( Figure 3 ).
[0030] Example 4:
[0031] The methylthio-modified Ce-MOF electrode material obtained in Example 1 was used as an electrode sensing material for the electrochemical detection of heavy metal ions. 2.0 mg of the methylthio-modified Ce-MOF was dispersed in 1.0 ml of water and sonicated for 30 minutes to form a uniform suspension. Subsequently, 8.0 μL of the suspension was deposited onto the exposed GCE surface and air-dried at room temperature to obtain the sensing working electrode. A platinum wire electrode served as the counter electrode, and a silver / silver chloride electrode served as the reference electrode.
[0032] Differential pulse stripping voltammetry (DPSV) was used to measure the Cd 2+ , Pb 2+ 、Cu 2+ and Hg 2+ ions were measured simultaneously, and DPSV measurements were performed with a deposition time of 10 s, a pulse width of 0.2 s, a potential range of -1.0 V to 0.4 V, an amplitude of 50 mV, and a potential increment of 5 mV. 2+ , Pb 2+ 、Cu 2+ and Hg 2+ The DPSV response currents of Cd increased with the increase of Cd concentration in the ranges of 0.06-4.0μM, 0.06-9.0μM, 0.06-9.5μM and 0.06-4.0μM, respectively. 2+ , Pb 2+ 、Cu 2+ and Hg2+ The concentration of Figure 4 , Figure 5 ).
[0033] Example 5:
[0034] The methylthio-modified Ce-MOF electrode material finally obtained in Example 1 was used as an electrode sensing material in the electrochemical detection of heavy metal ions. 2.0 mg of methylthio-modified Ce-MOF was dispersed in 1.0 ml of water and ultrasonicated for 30 minutes to form a uniform suspension. Subsequently, 8.0 μL of the suspension was deposited on the exposed GCE surface and air-dried at room temperature to obtain a sensing working electrode. The platinum wire electrode was used as the counter electrode, and the silver / silver chloride electrode was used as the reference electrode. Heavy metal ion solutions of different concentrations (0.08 μM and 5.0 μM) were added to commercial apple juice, laboratory pure water, and river water, respectively. As shown in Tables 1, 2, and 3, the relative standard deviation of the detection concentration of heavy metal ions was between 1.7% and 4.4%.
[0035] Table 1 Determination of various heavy metal ions in fruit juice
[0036]
[0037] Table 2 Determination of various heavy metal ions in pure water
[0038]
[0039]
[0040] Table 3 Determination of various heavy metal ions in river water
[0041]
Claims
1. A method for preparing a methylthio-modified Ce-MOF electrode material, characterized in that: The method involves weighing cerium ammonium nitrate, methylthioterephthalic acid, and acetic acid in a glass vial and dissolving them in DMF. The mixture is stirred for 15 minutes, then transferred to a round-bottom flask and reacted in an oil bath at 35°C for 24 hours to form a yellow solution. The product is collected by centrifugation, washed with ethanol and acetone, and finally dried under vacuum to obtain a methylthio-modified Ce-MOF electrode material.
2. The preparation method according to claim 1, characterized in that In molar ratio, ammonium cerium nitrate and methylthioterephthalic acid = 1:
1.
3. The preparation method according to claim 1, characterized in that The preparation method of methylthioterephthalic acid comprises the following steps: dissolving 2,5-dimercaptoterephthalic acid in acetone, adding K2CO3, and dropwise adding iodomethane with stirring. The mixture is stirred at room temperature for 1 hour, and then excess solvent is removed under vacuum. The resulting residue is dissolved in deionized water and cooled to 0°C. The pH of the solution is then adjusted to 1.5 with 2M hydrochloric acid. The precipitated solid is filtered, washed with cold water, and air-dried overnight to obtain methylthioterephthalic acid as a yellow solid powder.
4. The preparation method according to claim 1, characterized in that The solvent DMF is first dried and dehydrated.
5. The preparation method according to claim 1, characterized in that After the mixed solution was evenly dispersed, it was reacted in an oil bath at 35°C for 24 hours.
6. The methylthio-modified Ce-MOF electrode material prepared according to the method of claim 1 is used as an electrode sensing material in electrochemical detection of Cd 2+ , Pb 2+ 、Cu 2+ and Hg 2+ Simultaneous detection.
7. The use according to claim 5, characterized in that The method is as follows: 2.0 mg of methylthio-modified Ce-MOF was dispersed in 1.0 ml of water and sonicated for 30 minutes to form a uniform suspension. Subsequently, 8.0 μL of the suspension was deposited onto the exposed GCE surface and air-dried at room temperature to form the sensing working electrode. A platinum wire electrode served as the counter electrode, and a silver / silver chloride electrode served as the reference electrode.
8. The use according to claim 5, characterized in that The electrochemical properties of the GCE sensing material were characterized by differential pulse stripping voltammetry (DPSV) in 1 M acetate buffer solution (pH = 5-8). DPSV measurements were performed under a deposition time of 5s-50s, a pulse width of 0.1s-1s, a potential range of -1.0V-1.4V, an amplitude of 5mV-50mV, and a potential increment of 1mV-5mV.