A metal-doped Prussian blue derivative and its preparation method and application

Abstract

The present invention discloses a metal-doped Prussian blue derivative and its preparation method and application. The metal-doped PBAs material provided by the present invention has the chemical formula: K x Fe y M 1‑y [Fe(CN)6] z nH2O, where 0

Description

Technical Field

[0001] The invention belongs to the technical field of detection and analysis materials, and particularly relates to a metal-doped Prussian blue derivative and a preparation method and application thereof. Background Art

[0002] The traditional all-solid-state potassium ion selective electrode consists of a three-layer structure consisting of an electrode substrate, a solid contact layer (also called a transduction layer), and an ion selective membrane. It has the following shortcomings: (a) the ion selective membrane has weak mechanical strength, high cost (generally referring to the ion carrier valinomycin used to prepare the membrane), poor biocompatibility, and is prone to leakage; (b) a water layer is formed between the transduction layer and the ion selective membrane, affecting the stability of the potential measurement; (c) Na+ ions with similar ionic radii are not stable. + K + (d) The electrode must be exposed to the target ion (K + ) The electrode needs to be immersed in the solution, which is cumbersome to operate; (e) The electrode has a short life and is not easy to preserve.

[0003] To this end, some studies have proposed a new all-solid-state ion-selective electrode structure, which is a two-layer structure consisting of an electrode substrate and Prussian blue analogs (PBAs). This structure can greatly simplify the electrode structure and improve the detection performance of the all-solid-state ion-selective electrode.

[0004] However, PBAs also have some problems that need to be addressed. First, the electrical conductivity of PBAs is relatively low. At high current densities, the transport of ions in the electrode material is restricted, which slows down the kinetics of the electrochemical reaction and makes it difficult for potassium ions to be deintercalated during cycling. Second, due to the presence of lattice defects, PBAs are prone to structural collapse and decreased cycling stability during electrochemical testing, which limits their performance and service life in practical applications. Third, the lattice of PBAs contains coordinated water molecules. During actual use, the presence of these coordinated water molecules may reduce the ion mobility in the electrolyte solution and increase the electrode resistance, thereby adversely affecting the overall performance of the electrode. Finally, the insufficient stability of PBAs can lead to a decrease in electrode performance during long-term use.

[0005] At the same time, currently developed ion-selective electrodes require a series of pretreatment steps before practical application. Typically, these electrodes need to be immersed in a solution of the target ion for at least 24 hours to reach a stable state. This process is not only time-consuming but also increases operational complexity and cost. For applications requiring rapid response, this lengthy pretreatment is clearly a significant limiting factor; it also leads to problems such as harsh storage conditions and a short shelf life for the electrodes.

[0006] In addition, existing ion-selective electrode technologies also require calibration with standard solutions during actual testing. This means that the electrode parameters must be adjusted using standard solutions of known concentration before each measurement to ensure the accuracy of the results. Although this method can effectively improve the measurement accuracy, it also prolongs the time of the entire test process and requires the test personnel to have certain professional knowledge and technical backgrounds.

[0007] In view of this, the present invention is specifically proposed. Summary of the Invention

[0008] The object of the present invention is to provide a metal-doped PBAs material and a preparation method thereof. This material has higher stability, higher conductivity, less water of crystallization content, and wider potassium ion diffusion channels in a complex environment. Furthermore, when this material is assembled into a potassium ion-selective electrode, it exhibits excellent selectivity, better cyclic stability, higher sensitivity, and lower detection limit.

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

[0010] In the first aspect, the present invention provides a metal-doped PBAs material, the chemical formula of which is as follows: K x Fe y M 1-y [Fe(CN)6] z ·nH2O, where 0 < x ≤ 2, y < 1, 0.5 < z < 1, 0 < n < 2, and M is one of Mn, Ni, and Cu.

[0011] Preferably, 1 ≤ x ≤ 1.5, 0.5 < y < 1, 0.5 < z < 1, 0 < n < 0.3, and M is Mn, Ni, or Cu.

[0012] In a specific embodiment of the present invention, the chemical formula of the metal-doped PBAs material is:

[0013] K 1.06 Fe 0.86 Cu 0.14 [Fe(CN)6] 0.63 ·0.66H2O; <000009​​​​​​​​​​​​​​​​​​​​

[0016] The present invention introduces transition metal elements into the lattice of potassium-rich PBAs materials, utilizing the electrochemical activity of the doped transition metals to participate in redox reactions, thereby synergizing with potassium to significantly improve the conductivity of the PBAs materials, accelerate the diffusion of potassium ions, and enhance the structural stability of the PBAs materials.

[0017] In a second aspect, the present invention provides a method for preparing the above-mentioned metal-doped PBAs material, comprising the following steps:

[0018] S1. Dissolve potassium ferrocyanide in a saturated potassium chloride solution to obtain a precursor solution A;

[0019] S2, dissolving the M metal salt and the iron salt in a saturated potassium chloride solution to obtain a precursor solution B;

[0020] S3. Precursor solution A and precursor solution B are mixed to react to obtain metal-doped PBAs material.

[0021] In step S1, the concentration of potassium ferrocyanide in the precursor solution A is in the range of 2-2.4 mmol / mL.

[0022] In step S2, the concentration range of the M element in the precursor solution B is 0.48-1.92 mmol / mL, and the concentration range of the Fe element is 0.48-1.92 mmol / mL.

[0023] In step S2, the M metal salt is one or more of manganese sulfate monohydrate, nickel sulfate hexahydrate and copper sulfate pentahydrate.

[0024] In step S3, the reaction is carried out according to the following operation: the precursor solution A is heated to 55-65°C, and then the precursor solution B is added dropwise to the precursor solution A at a rate of 1 ml / min, vacuumed, nitrogen is introduced, and then stirred at a speed of 550-650 rpm / min for 11-13 hours at a temperature of 55-65°C; allowed to stand for 11-13 hours; the generated precipitate is washed several times with deionized water and ethanol respectively; then centrifuged at 2900-3100r for 4-6 minutes, and then vacuum dried at 75-85°C for 11-13 hours.

[0025] In a third aspect, the present invention provides an all-solid-state potassium ion selective electrode using the above-mentioned metal-doped PBAs material.

[0026] In a specific embodiment of the present invention, an all-solid-state potassium ion selective electrode comprises: an electrode substrate and a sensing membrane; the sensing membrane is formed of the above-mentioned metal-doped PBAs material.

[0027] In a fourth aspect, the present invention also provides a method for preparing an all-solid-state potassium ion selective electrode, comprising the following steps: preparing the above-mentioned metal-doped PBAs material into a suspension; dropping the suspension onto the surface of the electrode substrate and drying it to obtain an all-solid-state potassium ion selective electrode.

[0028] The suspension was prepared by mixing the metal-doped PBAs with PVDF and NMP and sonicating at a frequency of 20 kHz to 100 kHz. The concentration of the metal-doped PBAs in the suspension was 20-30 mg / mL, and the concentration of PVDF was 5-10 mg / mL.

[0029] The electrode substrate can be selected from glassy carbon electrodes, screen-printed electrodes, gold electrodes, and platinum electrodes.

[0030] The electrode substrate is pretreated before the material is added. The specific process includes: polishing the surface of the electrode substrate with Al2O3 particles with a particle size of 0.3 and 0.05 μm, and ultrasonically treating them in ultrapure water, ethanol, and ultrapure water for 5 minutes respectively, and using compressed nitrogen to blow dry the electrode for standby use. In addition, the consistency of each step should be ensured as much as possible during the pretreatment process to ensure reproducibility between electrodes. Secondary contamination, especially chemical and biological contamination, should be avoided during the treatment process. The pretreated electrode should be used as soon as possible to avoid re-attachment of pollutants in the air.

[0031] The drying conditions are: temperature of 55-65° C. and time of 2-4 hours.

[0032] In a specific test application of the all-solid-state potassium ion selective electrode of the present invention, the serum diluent used is prepared according to the following operation: 0.2964g NaH2PO4·2H2O, 2.9g Na2HPO4·12H2O and 8g NaCl are dissolved in a 1L volumetric flask.

[0033] In a specific embodiment of the present invention, the all-solid-state potassium ion selective electrode can be used for three-electrode testing, wherein the reference electrode is a silver / silver chloride electrode (or a calomel reference electrode), the counter electrode is a platinum sheet electrode, and the all-solid-state potassium ion selective electrode prepared above is the working electrode.

[0034] The all-solid-state potassium ion selective electrode of the present invention is not only applicable to a three-electrode system, but can also be used in a two-electrode system. In the two-electrode system, the working electrode and the reference electrode work together to achieve specific electrochemical measurements.

[0035] In a fifth aspect, a method for detecting potassium ion concentration comprises using the above-mentioned all-solid-state potassium ion selective electrode to detect a sample; the sample comprises untreated sweat, serum, or whole blood.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] 1. The metal-doped PBAs provided by the present invention have higher stability, higher conductivity, less crystalline water content, and more spacious potassium ion diffusion channels in complex environments, which enables the material to exhibit excellent selectivity, better cycle stability, higher sensitivity, and lower detection limit when assembled into potassium ion selective electrodes.

[0038] 2. By strictly controlling the temperature, rotation speed, and dripping frequency, the present invention can effectively control the membrane potential, thereby realizing calibration-free instrument testing (such as pretreatment steps such as soaking and storage in potassium chloride solution). The resulting electrode can accurately detect potassium ions in sweat, serum, and whole blood, greatly extending the service life of the electrode and ensuring a long shelf life for commercial electrodes.

[0039] 3. The present invention adopts the solution co-precipitation method to synthesize metal-doped PBA materials. The preparation process is not only simple and easy, but also low-cost, and conforms to the green and environmentally friendly production concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 are the SEM (AG) and XRD patterns (H) of metal-doped PBAs materials.

[0041] Figure 2 Potassium ion diffusion rate test of metal-doped PBAs materials.

[0042] Figure 3 is the potassium ion diffusion coefficient of metal-doped PBAs.

[0043] Figure 4 Nernst response slope and potential drift of metal-doped PBAs.

[0044] Figure 5 The potential drift of metal-doped PBAs.

[0045] Figure 6 This is the result of using the electrode provided by the present invention to detect potassium ion concentration in serum. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to specific examples, but the present invention is not limited to the following examples.

[0047] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0048] Unless otherwise specified, the reagents, materials, instruments, etc. used in the following examples can be obtained from commercial sources.

[0049] Example 1

[0050] This embodiment provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0051] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0052] (2) Dissolve 1.6 mmol of manganese sulfate monohydrate solution and 0.8 mmol of ferrous sulfate heptahydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0053] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B to the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; the generated precipitate was washed three times with deionized water and ethanol in turn, and dried in a vacuum oven at 80°C for 12 hours to obtain the metal-doped PBAs material KFeMn-PBAs. Combined with the ICP-Mass test results, its chemical formula is K 1.27 Fe 0.66 Mn 0.34 [Fe(CN)6] 0.62 0.21H2O.

[0054] Example 2

[0055] This embodiment provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0056] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0057] (2) Dissolve 1.6 mmol of copper sulfate pentahydrate solution and 0.8 mmol of ferrous sulfate heptahydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0058] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B dropwise into the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; wash the resulting precipitate three times with deionized water and ethanol in turn, and dry it in a vacuum oven at 80°C for 12 hours to obtain the metal-doped PBAs material KFeCu-PBAs. Combined with the ICP-Mass test results, its chemical formula is K 1.06 Fe 0.86 Cu 0.14 [Fe(CN)6] 0.63 0.66H2O.

[0059] Example 3

[0060] This embodiment provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0061] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0062] (2) Dissolve 1.6 mmol of nickel sulfate hexahydrate solution and 0.8 mmol of ferrous sulfate heptahydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0063] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B to the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; the generated precipitate was washed three times with deionized water and ethanol in turn, and dried in a vacuum oven at 80°C for 12 hours to obtain the metal-doped PBAs material KFeNi-PBAs. Combined with the ICP-Mass test results, its chemical formula is K 1.14 Fe 0.84 Ni 0.16 [Fe(CN)6] 0.62 0.26H2O.

[0064] Comparative Example 1

[0065] This comparative example provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0066] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0067] (2) Dissolve 2.4 mmol of ferrous sulfate heptahydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0068] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B to the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; the generated precipitate is washed three times with deionized water and ethanol in turn, and dried in a vacuum oven at 80°C for 12 hours to obtain the doped PBAs material KFe-PBAs, whose chemical formula is K 1.75 Fe[Fe(CN)6] 0.84 0.54H2O.

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0071] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0072] (2) Dissolve 2.4 mmol of manganese sulfate monohydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0073] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B to the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; the generated precipitate is washed three times with deionized water and ethanol in turn, and dried in a vacuum oven at 80°C for 12 hours to obtain the doped PBAs material KMn-PBAs, whose chemical formula is K 1.75 Mn[Fe(CN)6] 0.84 0.94H2O.

[0074] Comparative Example 3

[0075] This comparative example provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0076] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0077] (2) Dissolve 2.4 mmol of copper sulfate pentahydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0078] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B to the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; the resulting precipitate is washed three times with deionized water and ethanol in turn, and dried in a vacuum oven at 80°C for 12 hours to obtain the doped PBAs material KCu-PBAs, whose chemical formula is K 1.72 Cu[Fe(CN)6] 0.85 1.30H2O.

[0079] Comparative Example 4

[0080] This comparative example provides a method for preparing a metal-doped PBA material, comprising the following steps:

[0081] (1) Dissolve 2 mmol of potassium ferrocyanide in 100 mL of saturated potassium chloride solution to obtain precursor solution A;

[0082] (2) Dissolve 2.4 mmol of nickel sulfate hexahydrate in 80 mL of saturated potassium chloride solution to obtain precursor solution B;

[0083] (3) Heat the precursor solution A to 60°C in an oil bath, slowly add the precursor solution B to the precursor solution A, evacuate the air in the flask with a syringe, introduce nitrogen, and heat and stir for 12 hours; let it stand at room temperature for 12 hours; the generated precipitate is washed three times with deionized water and ethanol in turn, and dried in a vacuum oven at 80°C for 12 hours to obtain the doped PBAs material KNi-PBAs, whose chemical formula is K 1.72 Ni[Fe(CN)6] 0.88 1.14H2O.

[0084] Example 4

[0085] This embodiment provides a method for preparing an electrode using metal-doped PBAs, comprising the following steps:

[0086] 4 mg of the Prussian blue analogue prepared in the above example was mixed with 1 mg of PVDF and 200 μL of NMP and sonicated for 30 minutes to obtain a membrane solution of the material. 10 μL of the membrane solution was dropped onto a glassy carbon electrode and dried at 60°C for 3 hours to obtain a membrane solution.

[0087] The materials obtained from the above embodiments and comparative examples were tested

[0088] 1. Analysis and testing of metal-doped PBAs

[0089] 1. Morphology and structure

[0090] Depend on Figure 1 It can be seen that by comparing with the standard XRD pattern of PBAs (JCPDS No: 52-1907), it can be confirmed that the metal-doped PBAs materials prepared in Examples 1-3 were successfully prepared. After software refinement, it can be seen that all materials have a monoclinic structure.

[0091] 2. Moisture content analysis

[0092] The mass lost between 0 and 250 degrees is the content of adsorbed water, and the mass lost between 250 and 350 degrees is the mass lost of interstitial water.

[0093] The results of moisture content analysis showed that the adsorbed water content of KFeMn-PBAs material was 1.04% and the interstitial water content was 0.61%, which were lower than those of KMn-PBAs (adsorbed water content was 6.08% and interstitial water content was 6.38%) and KFe-PBAs (adsorbed water content was 3.61% and interstitial water content was 1.46%).

[0094] The adsorbed water content of KFeCu-PBAs material is 3.12% and the interstitial water content is 3.42%, which are lower than those of KCu-PBAs (adsorbed water content is 8.18% and interstitial water content is 5.12%) and KFe-PBAs (adsorbed water content is 3.61% and interstitial water content is 1.46%) PBAs materials.

[0095] The adsorbed water content of KFeNi-PBAs material is 1.24% and the interstitial water content is 1.76%, which are lower than those of PBAs materials KNi-PBAs (adsorbed water content is 6.94% and interstitial water content is 2.59%) and KFe-PBAs (adsorbed water content is 3.61% and interstitial water content is 1.46%).

[0096] From the above results, it can be seen that the adsorbed water and interstitial water contents of multi-metal co-doped PBAs materials are effectively reduced.

[0097] 3. Potassium ion diffusion rate test

[0098] The electrochemical workstation cyclic voltammetry method was used, and a three-electrode system was used at 10 -1 The curves under different current densities (0.05mV / s, 0.1mV / s, 0.3mV / s, 0.5mV / s, 0.8mV / s, 1mV / s) tested in KCl solution are as follows: Figure 2 According to the Randles-Sevcik equation, the diffusion coefficient of potassium ions in different electrodes is calculated.

[0099] Depend on Figure 3 It can be seen that the metal-doped PBAs prepared in Examples 1-3 of the present invention have a larger potassium ion diffusion coefficient, which proves that potassium ions migrate faster in this type of material.

[0100] 4. Electrode sensitivity, stability and detection limit

[0101] The open circuit potential-time method of the electrochemical workstation was selected, and a three-electrode system was used at 10 -5 , 10 -4 , 10 -3 , 10 -2 , 10 -1 The sensitivity of the electrode was tested in KCl solution.

[0102] The electrochemical workstation chronopotentiometry was used, and a three-electrode system was used at 10 -1 The stability of the electrode was tested by applying a constant current of +1 nA for 60 s and then applying a constant current of -1 nA for 60 s in KCl solution.

[0103]

[0104] Depend on Figure 4 As shown in Table 1, the electrode response slopes of KFeCu-PBAs, KFeNi-PBAs and KFeMn-PBAs are 56 mV·dec -1 、63mV·dec -1 and 68mV·dec -1 , while the response slopes of KCu-PBAs, KNi-PBAs, KMn-PBAs, and KFe-PBAs were 34 mV·dec -1 、36mV·dec -1 、47mV·dec -1 、51mV·dec -1 ; By comparison, the theoretical slope based on the electrode is 59 mV·dec -1 The present invention reduces the response slope of KFe-PBAs to 51 mV·dec by metal doping. -1 Increased to 56mV·dec -1 , achieving an effective improvement, while KFeNi-PBAs and KFeMn-PBAs have more sensitive response speeds.

[0105] Depend on Figure 5 As shown in Table 1, the potential drift of KFeCu-PBAs within 60s was 0.8mV, which is much lower than the 2.2mV of monometallic KCu-PBAs. The potential drift of KFeNi-PBAs within 60s was 0.4mV, which is much lower than the 0.9mV of monometallic KNi-PBAs. The potential drift of KFeMn-PBAs within 60s was 0.2mV, which is much lower than the 0.8mV of monometallic KMn-PBAs. It can be seen that the material obtained by the present invention has excellent stability.

[0106] The capacitance values ​​calculated using the formula ΔE / Δt=i / C show that the capacitance values ​​of the KFeCu-PBAs, KFeNi-PBAs, and KFeMn-PBAs prepared by the present invention are 75, 150, and 300 uF, respectively. The materials prepared by the present invention have high capacitance and good electrode conductivity.

[0107] By measuring 10 -7 -10 -1 M KCl solution, the detection limit of the metal-doped PBAs material provided by the present invention is calculated to be 10 -5.5 mM (KFeMn-PBAs), 10 -5.3 mM (KFeNi-PBAs), 10 -5.25 mM (KFeCu-PBAs).

[0108] 5. Metal-doped PBAs for the detection of potassium ion concentration in serum

[0109] First, a standard curve is obtained by measuring a ten-fold diluted commercial potassium ion solution (test solution is 0.4mM, 0.8mM). Then, the potential value of the ten-fold diluted rabbit serum is measured and substituted into the above equation to successfully measure the rabbit serum content.

[0110] like Figure 6 As shown, the results of multiple electrode tests are similar, with an average value of 5.15mM. The content of rabbit serum was tested by turbidimetry, and the result obtained was 5.35mM. This shows that the material obtained by the present invention can be directly used for serum testing without calibration.

[0111] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for preparing metal-doped PBAs, characterized in that: The steps include: S1. Dissolve potassium ferrocyanide in a saturated potassium chloride solution to obtain a precursor solution A; S2, dissolving the M metal salt and the iron salt in a saturated potassium chloride solution to obtain a precursor solution B; S3, mixing precursor solution A and precursor solution B to react and obtain metal-doped PBAs material; In step S3, the reaction is carried out according to the following operation: the precursor solution A is heated to 55-65° C., and then the precursor solution B is added dropwise to the precursor solution A at a rate of 1 ml / min, vacuumed, nitrogen is introduced, and then stirred at a temperature of 55-65° C. and a speed of 550-650 rpm / min for 11-13 hours; the mixture is allowed to stand for 11-13 hours; the generated precipitate is washed several times with deionized water and ethanol respectively; then centrifuged at 2900-3100 r for 4-6 minutes, and then vacuum dried at 75-85° C. for 11-13 hours; The chemical formula of the metal-doped PBAs material is as follows: K x Fe y M 1-y [Fe(CN)6] z ·nH2O, where 1 ≤ x ≤ 1.5, 0.5 < y < 1, 0.5 < z < 1, 0 < n < 0.3, and M is Mn, Ni, or Cu.

2. The preparation method according to claim 1, characterized in that In step S1, the concentration of potassium ferrocyanide in the precursor solution A is in the range of 2-2.4 mmol / mL.

3. The preparation method according to claim 1, characterized in that In step S2, in the precursor solution B, the concentration range of the Fe element is 0.48-1.92 mmol / mL, and the concentration range of the M element is 0.48-1.92 mmol / mL.

4. The preparation method according to claim 1, wherein In step S2, the M metal salt is one or more of manganese sulfate monohydrate, nickel sulfate hexahydrate and copper sulfate pentahydrate.

5. The metal-doped PBAs material obtained by the preparation method according to any one of claims 1 to 4.

6. An all-solid-state potassium ion selective electrode, comprising the metal-doped PBAs material according to claim 5.

7. The all-solid-state potassium ion selective electrode according to claim 6, characterized in that include: Electrode substrate, sensing membrane; The sensing film is formed of the metal-doped PBAs material.

8. A method for detecting potassium ion concentration for purposes other than disease diagnosis and treatment, comprising detecting a sample using the metal-doped PBAs material of claim 5.

Images