Ammonium ion selective electrode

Abstract

The utility model discloses an ammonium ion selective electrode and belongs to the technical field of water quality monitoring. A first ion selection working electrode, a second ion selection working electrode and a reference electrode assembly are arranged in an electrode main body shell in the ammonium ion selection electrode; a first ion-selective membrane in the first ion-selective working electrode contains abscisic acid, and a second ion-selective membrane in the second ion-selective working electrode contains valinomycin. According to the ammonium ion selective electrode disclosed by the utility model, the first ion selective working electrode adopting the aseptic as an ion selective carrier is used for detecting ammonium ions and potassium ions at the same time, and the second ion selective working electrode adopts valinamycin as a potassium ion selective carrier. By measuring the potential difference between the two ion working electrodes, the quantitative detection of ammonium ions is realized, and the selectivity and the sensitivity are enhanced.

Description

Technical Field

[0001] This utility model relates to the field of water quality monitoring technology, and more specifically, to an ammonium ion selective electrode. Background Technology

[0002] Ammonia nitrogen is an important water quality monitoring indicator in urban sewage and industrial wastewater treatment, as well as in aquaculture water. Accurate measurement of its concentration is crucial for pollution control and environmental protection. Ammonium ions (NH4+) + Ion-selective electrodes (ISEs) are commonly used electrochemical sensors that provide a rapid, sensitive, and economical method for ammonia nitrogen detection. However, current ammonium ion-selective electrodes still face some challenges in online environmental monitoring applications, requiring further improvement and enhancement of their performance.

[0003] Firstly, ammonium ion-selective electrodes typically use non-vitamin-containing ion-selective carriers; however, these carriers are not effective against ammonium ions (NH4+). + and potassium ions K + Having the same selectivity, they are easily affected by potassium ions in the environmental water, resulting in higher values. Therefore, for environmental monitoring applications, it is necessary to integrate ammonium ion and potassium ion selective electrodes simultaneously.

[0004] Secondly, the reference electrode in ion-selective electrodes usually adopts a single salt bridge structure. For Ag / AgCl reference electrodes, the electrolyte is usually saturated potassium chloride. During operation, the electrolyte gradually leaks into the environmental water. On the one hand, the leaked potassium ions interfere with the ammonium ion-selective electrode. On the other hand, the consumption and leakage of the electrolyte make the electrode require frequent maintenance and replacement, which increases the cost and complexity of use.

[0005] Third, in wastewater treatment and natural water body monitoring, microorganisms attached to the surface of the electrode ion-selective membrane will form a biofilm, which will affect the response speed and detection accuracy of the electrode. Using a cleaning brush can easily damage the electrode membrane and shorten the service life of the electrode. Utility Model Content

[0006] 1. Technical problem to be solved by the utility model

[0007] In existing technologies, when using abacterial-free viable bacteria as the ion selection carrier in ammonium ion selective electrodes, the ammonium ion NH4+... + Susceptible to potassium ions (K) in the surrounding water + To address the problem of inaccurate detection results caused by interference, an ammonium ion selective electrode is provided.

[0008] 2. Technical Solution

[0009] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0010] This invention relates to an ammonium ion selective electrode.

[0011] Includes the electrode body and the electrode tail end connected to the electrode body;

[0012] The electrode body includes an electrode body shell and a front end cap connected to the electrode body shell;

[0013] The electrode body housing contains a first ion-selective working electrode, a second ion-selective working electrode, and a reference electrode assembly.

[0014] The first ion-selective working electrode includes a first ion-selective membrane, a first working electrode tube, and a first working electrode tail plug connected in sequence.

[0015] The first working electrode tube is inserted into the front end cap, and the first ion-selective membrane contains a live bacterium (CAS: 6833-84-7).

[0016] The first ion-selective membrane can be the ammonium ion-selective membrane described in the reference [Fabrication of an All-Solid-State Ammonium Paper Electrode Using a Graphite-Polyvinyl Butyral Transducer Layer. Chemosensors, November 2021, Vol. 9, No. 12].

[0017] The second ion-selective working electrode includes a second ion-selective membrane, a second working electrode tube, and a second working electrode tail plug connected in sequence.

[0018] The second working electrode tube is inserted into the front end cap, and the second ion-selective membrane contains valinemycin (CAS: 2001-95-8);

[0019] The second ion-selective membrane can be the potassium ion-selective membrane formed from mixture 1 as described in the reference [Potassium-selective conductometric sensor. Sensors and Actuators B: Chemical, June 2001, Vol. 76, No. 1-3].

[0020] The reference electrode assembly includes a first porous material component, a reference electrode tube, and a reference electrode tail plug connected in sequence.

[0021] The first working electrode tube has several through holes at one end;

[0022] The second working electrode tube has several through holes at one end;

[0023] The front end cap is provided with a second porous material component.

[0024] Furthermore, the outer shell of the electrode body is used to fill NaCl solution;

[0025] The first ion-selective working electrode is used to fill NH4Cl solution;

[0026] The second ion-selective working electrode is used to fill KCl solution;

[0027] The reference electrode assembly is used to fill the KCl solution.

[0028] Furthermore, the first ion-selective working electrode also includes a first reference electrode, which is disposed at the end plug of the first working electrode.

[0029] Furthermore, the second ion-selective working electrode also includes a second reference electrode, which is disposed at the end plug of the second working electrode.

[0030] Furthermore, the reference electrode assembly also includes a third reference electrode, which is disposed at the end plug of the reference electrode.

[0031] Furthermore, the first porous material component is a ceramic filter element;

[0032] The second porous material component is a ceramic filter element.

[0033] Specifically, the ceramic filter element can be a porous ceramic filter element.

[0034] Furthermore, the first ion-selective working electrode also includes a first front end cap, which is sleeved on the first working electrode tube body.

[0035] Furthermore, the second ion-selective working electrode also includes a second front end cap, which is sleeved on the body of the second working electrode tube.

[0036] Furthermore, the first working electrode tube body includes a first connecting tube body and a second connecting tube body connected in sequence;

[0037] The first connecting tube body is inserted into the front end cap;

[0038] The first front end cap is fitted onto the first connecting tube body, and a first ion-selective membrane is disposed between the first front end cap and the first connecting tube body.

[0039] Furthermore, the second working electrode tube body includes a third connecting tube body and a fourth connecting tube body connected in sequence;

[0040] The third connecting tube is inserted into the front end cap;

[0041] The second front end cap is fitted onto the third connecting tube body, and a second ion-selective membrane is provided between the second front end cap and the third connecting tube body.

[0042] Furthermore, the front end cap is connected to a filter component;

[0043] The filtering component is equipped with a filter screen and a vibration assembly.

[0044] Furthermore, the filter component includes a filter cylinder and a protective tail cap;

[0045] A filter screen is provided on the filter cylinder;

[0046] The protective tail cover is equipped with a vibration component.

[0047] Furthermore, the electrode body also includes a fixing cover plate;

[0048] The fixed cover plate is connected to the outer shell of the electrode body.

[0049] Furthermore, the fixing cover plate is provided with through holes for fixing the first ion-selective working electrode, the second ion-selective working electrode, and the reference electrode assembly.

[0050] Furthermore, a circuit board is provided inside the tail end of the electrode;

[0051] The main circuit board includes a microcontroller chip and its auxiliary circuits, an RS485 communication circuit, a power management module, an ultrasonic transducer driver module, and a signal operational amplifier acquisition circuit.

[0052] Furthermore, the first reference electrode, the second reference electrode, and the third reference electrode are connected to the circuit board.

[0053] 3. Beneficial effects

[0054] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0055] (1) The ammonium ion selective electrode provided by this utility model uses a sterile ion carrier as the first ion selective working electrode to simultaneously detect ammonium ions and potassium ions, and a valacyclovir as the potassium ion selective working electrode. By measuring the potential difference between the two ion working electrodes, quantitative detection of ammonium ions is achieved, enhancing selectivity and sensitivity;

[0056] It has a built-in reference electrode with dual salt bridges, and uses the internal cavity of the electrode body shell as the external salt bridge part, which can increase the electrolyte storage capacity, provide a more stable reference potential and a longer electrode life.

[0057] (2) The ammonium ion selective electrode provided by this utility model can prevent suspended particulate matter from adhering to the ion selective membrane through the filter component. At the same time, the vibration component can remove the biofilm formed by microorganisms adhering to the ion selective membrane through vibration, without damaging the ion selective membrane, which is conducive to maintaining the cleanliness and performance stability of the electrode. Attached Figure Description

[0058] Figure 1 This is a partial exploded view of an ammonium ion selective electrode according to Embodiment 1 of this utility model.

[0059] Figure 2 This is a partial exploded view of the electrode body in Embodiment 1 of this utility model.

[0060] Figure 3 This is an exploded view of the electrode body in Embodiment 1 of this utility model.

[0061] Figure 4 This utility model Figure 3 A cross-sectional view of the connection structure of the working electrode tube, the front end cap, the ion-selective membrane, and the front end cap.

[0062] Figure 5 This is a partial exploded view of an ammonium ion selective electrode in Embodiment 2 of this utility model.

[0063] Figure 6 This is an exploded view of an ammonium ion selective electrode according to Embodiment 2 of this utility model.

[0064] Figure 7 This is a cross-sectional view of a protective tail cap according to Embodiment 2 of this utility model.

[0065] Explanation of the labels in the diagram:

[0066] 100. Electrode tail end; 110. Circuit board;

[0067] 200. Electrode body; 210. Electrode body outer shell;

[0068] 220. First ion-selective working electrode; 221. First working electrode tube body; 2211. First connecting tube body; 2212. Second connecting tube body; 222. Tail plug of the first working electrode; 223. First reference electrode; 224. First front end cap; 225. First ion-selective membrane;

[0069] 230. Second ion-selective working electrode; 231. Second working electrode tube body; 2311. Third connecting tube body; 2312. Fourth connecting tube body; 232. Tail plug of the second working electrode; 233. Second reference electrode; 234. Second front end cap; 235. Second ion-selective membrane;

[0070] 240. Reference electrode assembly; 241. First porous material component; 242. Reference electrode tube body; 243. Reference electrode tail plug; 244. Third reference electrode;

[0071] 250. Fixed cover plate;

[0072] 260. Front end cap; 261. Second porous material component; 262. Fixing plate; 263. Connecting ring;

[0073] 300. Filter component; 310. Filter cylinder; 320. Protective tail cap; 321. Vibration assembly; 330. Wire. Detailed Implementation

[0074] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0075] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0076] Example 1

[0077] Combination Figures 1-3An ammonium ion selective electrode according to this embodiment includes an electrode body 200 and an electrode tail end 100 connected to the electrode body 200. The electrode body 200 includes an electrode body shell 210 and a front end cap 260 connected to the electrode body shell 210; a first ion selective working electrode 220, a second ion selective working electrode 230, and a reference electrode assembly 240 are disposed inside the electrode body shell 210; the first ion selective working electrode 220 includes a first ion selective membrane 225, a first working electrode tube 221, and a first working electrode tail plug 222 connected in sequence; the first working electrode tube 221 is inserted into the front end cap 260, and the first ion selective membrane 225 contains a viable bacterium; wherein, the viable bacterium is effective against ammonium ions NH4+. + and potassium ions K + It has the same selectivity. The second ion-selective working electrode 230 includes a second ion-selective membrane 235, a second working electrode tube 231, and a second working electrode tail plug 232 connected in sequence; the second working electrode tube 231 is inserted into the front end cap 260, and the second ion-selective membrane 235 contains valamethoxam; wherein, valamethoxam mainly targets potassium ions K + It is selective. The reference electrode assembly 240 includes a first porous material component 241, a reference electrode tube 242, and a reference electrode tail plug 243 connected in sequence; a second porous material component 261 is provided on the front end cap 260. One end of the first working electrode tube 221 is provided with several through holes; one end of the second working electrode tube 231 is provided with several through holes. As a specific embodiment, the electrode body 200 and the electrode tail end 100 can be detachably connected, for example, they can be connected by a threaded connection. The front end cap 260 and the electrode body shell 210 can be detachably connected, for example, they can be connected by a snap-fit ​​connection.

[0078] It should be noted that the first ion-selective working electrode 220, using valproic acid as the ion-selective carrier, simultaneously detects ammonium and potassium ions, while the second ion-selective working electrode 230 uses valproic acid as the potassium ion-selective carrier. By measuring the potential difference between the two ion-selective working electrodes, quantitative detection of ammonium ions is achieved, enhancing selectivity and sensitivity.

[0079] As an optional implementation, a first porous material is inserted into the reference electrode tube 242, and a second porous material component 261 is inserted into the front end cap 260. A first ion-selective membrane 225 is bonded to one end of the first working electrode tube 221 where a plurality of through holes are provided, and a second ion-selective membrane 235 is bonded to one end of the second working electrode tube 231 where a plurality of through holes are provided. Specifically, bonding can be achieved using adhesives such as epoxy resin AB glue.

[0080] Both the first working electrode tube 221 and the second working electrode tube 231 can be cylindrical tubes made of polyvinyl chloride (PVC) plastic. The several through holes at one end of the first working electrode tube 221 can be arranged in a ring; similarly, the several through holes at one end of the second working electrode tube 231 can be arranged in a ring. The reference electrode tube 242 can be a cylindrical tube made of PVC plastic or glass. Both the first porous material component 241 and the second porous material component 261 can be ceramic filter elements; specifically, the ceramic filter element can be cylindrical. The shape of the first porous material component 241 can be adjusted according to the shape of the reference electrode tube.

[0081] Furthermore, the electrode body shell 210 is used to fill NaCl solution; the first ion-selective working electrode 220 is used to fill NH4Cl solution; the second ion-selective working electrode 230 is used to fill KCl solution; and the reference electrode assembly 240 is used to fill KCl solution. The NaCl solution inside the electrode body shell 210 serves as an external salt bridge, and the electrode solution leaks into the ambient water through the second porous material component 261 on the front end cap 260. By incorporating the reference electrode assembly 240 with dual salt bridges, and utilizing the internal cavity of the electrode body shell 210 as the external salt bridge portion, the electrolyte storage capacity can be increased, providing a more stable reference potential and a longer electrode lifespan.

[0082] Furthermore, the first ion-selective working electrode 220 also includes a first reference electrode 223, which passes through the end cap 222 of the first working electrode. The second ion-selective working electrode 230 also includes a second reference electrode 233, which passes through the end cap 232 of the second working electrode. The reference electrode assembly 240 also includes a third reference electrode 244, which passes through the end cap 243 of the reference electrode. After the first reference electrode 223, the second reference electrode 233, and the third reference electrode 244 pass through the end cap, they can be sealed with silicone to improve the sealing performance of the tube and reduce leakage and seepage. As a specific embodiment, the first reference electrode 223, the second reference electrode 233, and the third reference electrode 244 can all be Ag / AgCl filaments, that is, silver wires coated with AgCl at one end.

[0083] Combination Figure 3 , Figure 4As an optional implementation, the first ion-selective working electrode 220 further includes a first front end cap 224, which is sleeved on the first working electrode tube 221. The second ion-selective working electrode 230 further includes a second front end cap 234, which is sleeved on the second working electrode tube 231. The first front end cap 224 and the second front end cap 234 can further fix the first ion-selective membrane 225 and the second ion-selective membrane 235, respectively. Moreover, the first front end cap 224 and the second front end cap 234 are provided with through holes, allowing water to come into contact with the first ion-selective membrane 225 and the second ion-selective membrane 235 for normal detection.

[0084] The first working electrode tube 221 includes a first connecting tube 2211 and a second connecting tube 2212 connected in sequence; the first connecting tube 2211 is inserted into a front end cap 260; a first front end cap 224 is sleeved on the first connecting tube 2211, and a first ion-selective membrane 225 is disposed between the first front end cap 224 and the first connecting tube 2211. The second working electrode tube 231 includes a third connecting tube 2311 and a fourth connecting tube 2312 connected in sequence; the third connecting tube 2311 is inserted into a front end cap 260; a second front end cap 234 is sleeved on the third connecting tube 2311, and a second ion-selective membrane 235 is disposed between the second front end cap 234 and the third connecting tube 2311.

[0085] By configuring both the first working electrode tube 221 and the second working electrode tube 231 as two detachable housings, and inserting the first connecting tube 2211 and the third connecting tube 2311 into the front end cap 260, it is easy to disassemble the first connecting tube 2211 and the third connecting tube 2311 to install and replace the first ion-selective membrane 225 on the first connecting tube 2211 and the second ion-selective membrane 235 on the third connecting tube 2311. As an optional implementation, the first connecting tube 2211 and the second connecting tube 2212 can be connected by a threaded connection or a slot connection; the third connecting tube 2311 and the fourth connecting tube 2312 can also be connected by a threaded connection or a slot connection. The first connecting tube 2211, the third connecting tube 2311, and the front end cap 260 can be an integral structure to improve sealing. The front end cap 260 can be connected to the electrode body housing 210 by a snap-fit ​​connection.

[0086] As one specific implementation, the front end cap 260 includes a fixing plate 262 and a connecting ring 263 connected to one side of the fixing plate 262. The first connecting tube 2211 and the third connecting tube 2311 are inserted into the fixing plate 262 and can be connected to the electrode body shell 210 by a snap-fit ​​connection through the outside of the connecting ring 263.

[0087] As an alternative implementation, the electrode body 200 further includes a fixing cover plate 250; the fixing cover plate 250 is connected to the electrode body shell 210. The fixing cover plate 250 has through holes for fixing the first ion-selective working electrode 220, the second ion-selective working electrode 230, and the reference electrode assembly 240. Specifically, the fixing cover plate 250 has through holes with the same outer diameter as the first working electrode tube 221, the second working electrode tube 231, and the reference electrode tube 242, to facilitate fixing the first ion-selective working electrode 220, the second ion-selective working electrode 230, and the reference electrode assembly 240. The through holes on the fixing cover plate 250 can also be interconnected, allowing for a more compact structure. The fixing cover plate 250 can be a circular plate, which can be adjusted according to the shape of the electrode body shell 210. The fixing cover plate 250 and the electrode body shell 210 can be connected by a snap-fit ​​mechanism.

[0088] Furthermore, a circuit board 110 is provided within the electrode tail end 100; the circuit board 110 includes a microcontroller chip and its auxiliary circuits, an RS485 communication circuit, a power management module, and a signal operational amplifier acquisition circuit. The signal operational amplifier acquisition circuit is used to follow the operational amplifier and acquire the signals from the first ion-selective working electrode 220 and the second ion-selective working electrode 230. The signal operational amplifier acquisition circuit can employ existing technology in the field and is not specifically limited.

[0089] The first reference electrode 223, the second reference electrode 233, and the third reference electrode 244 are connected to the circuit board 110. In one specific implementation, they can be connected to the circuit board 110 by soldering.

[0090] The working principle of the ammonium ion selective electrode in this embodiment is as follows: by measuring the potential difference between the first ion selective working electrode 220 and the second ion selective working electrode 230 relative to the reference electrode assembly 240, a potential relationship with ammonium ions (NH4+) is established. + and potassium ions K + The linear regression curve of ammonium ions (NH4) was obtained to achieve the control of ammonium ions. + Accurate detection. Specifically, this means: the first ion-selective working electrode 220 for NH4+ + and K + Both are selective, but the second ion-selective working electrode 230 is only selective for K+. +It is selective. First, the first ion-selective working electrode 220 measures NH4. + Standard solution, to obtain C A,NH4 + -E A,NH4 + A standard curve of (ammonium ion concentration - ammonium ion potential) is formed, with its slope being k1; then K is measured. + Standard solution, to obtain C A,K + -E A,K + A standard curve of (potassium ion concentration - potassium ion potential) is formed, with its slope being k2; finally, the second ion selection working electrode 230 is used to measure K. + Standard solution, to obtain C B,K + -E B,K + A standard curve (potassium ion concentration - potassium ion potential) is plotted, with a slope of k3. When measuring actual water samples, the potential value E of the second ion-selective working electrode 230 can be read. B,K + , by C B,K + -E B,K + The standard curve can be used to obtain K in actual water samples + Concentration C K + , Then by C A,K + -E A,K + The standard curve yields the first ion-selective working electrode 220 K. + Potential value E A,K + , Finally, the potential value E of the first ion-selective working electrode 220 can be read. A Because of E A =E A,NH4 + +E A,K + Therefore, the first ion-selective working electrode 220 for NH4 can be obtained. + Potential value E A,NH4 + , make Right now Then by C A,NH4 + -E A,NH4 + The standard curve can be used to calculate the NH4 content in actual water samples. + Concentration C NH4+ ,

[0091] Example 2

[0092] The ammonium ion selective electrode in this embodiment is basically the same as in Embodiment 1, except that:

[0093] A filter element 300 is connected to the front end cap 260. The filter element 300 is equipped with a filter screen and a vibration assembly 321. A first ion-selective membrane 225 and a second ion-selective membrane 235 are disposed within the filter element 300, effectively preventing suspended particulate matter in the water from adhering to the ion-selective membranes and reducing their impact on the detection site. The vibration assembly 321 in the filter element 300 vibrates to remove biofilm formed by microorganisms adhering to the ion-selective membranes, without damaging the membranes and maintaining the cleanliness and performance stability of the electrodes. Simultaneously, vibration can also remove suspended particulate matter from the surface of the filter screen, thus improving the filtration effect. As an optional implementation, the vibration assembly 321 can be directly installed on the filter screen.

[0094] In one optional implementation, the filter component 300 includes a filter cylinder 310 and a protective cap 320; the filter cylinder 310 is provided with a plurality of filter screens; and a vibration component 321 is provided inside the protective cap 320. In another optional implementation, a first ion-selective membrane 225 and a second ion-selective membrane 235 are housed within the filter cylinder 310. The filter cylinder 310 has a plurality of through holes, and filter screens are installed within these through holes to filter suspended particulate matter in the water. The vibration component 321 is provided inside the protective cap 320 to generate vibrations to clean the ion-selective membranes and filter screens. Specifically, the shape of the through holes can be circular, square, etc., without specific limitations. The filter screens can be metal or plastic. The mesh size of the filter screens can be 200 mesh. The vibration component 321 can be an ultrasonic transducer.

[0095] The main circuit board 110 also includes an ultrasonic transducer drive module for controlling the vibration of the vibration component 321. As an optional implementation, the vibration component 321 in the protective tail cover 320 can be connected to the main circuit board 110 via wires 330. Specifically, the protective tail cover 320 and the electrode body housing 210 have through holes, through which the wires 330 pass to connect the vibration component 321 to the main circuit board 110. This connection can be made via pins, which helps ensure stable transmission of current and signals. There can be two wires 330, with a corresponding number of through holes.

[0096] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. An ammonium ion selective electrode, characterized in that: It includes an electrode body (200) and an electrode tail end (100) connected to the electrode body (200). The electrode body (200) includes an electrode body shell (210) and a front end cap (260) connected to the electrode body shell (210). The electrode body shell (210) is provided with a first ion-selective working electrode (220), a second ion-selective working electrode (230), and a reference electrode assembly (240). The first ion-selective working electrode (220) includes a first ion-selective membrane (225), a first working electrode tube (221), and a first working electrode tail plug (222) connected in sequence. One end of the first working electrode tube (221) is provided with several through holes. The first working electrode tube (221) is inserted into the front end cap (260), and the first ion-selective membrane (225) contains abacterial spores; The second ion-selective working electrode (230) includes a second ion-selective membrane (235), a second working electrode tube (231), and a second working electrode tail plug (232) connected in sequence. One end of the second working electrode tube (231) is provided with several through holes. The second working electrode tube (231) is inserted into the front end cap (260), and the second ion-selective membrane (235) contains valinemycin; The reference electrode assembly (240) includes a first porous material component (241), a reference electrode tube (242), and a reference electrode tail plug (243) connected in sequence. The front end cap (260) is provided with a second porous material component (261).

2. The ammonium ion selective electrode according to claim 1, characterized in that: The electrode body shell (210) is used to fill NaCl solution; The first ion-selective working electrode (220) is used to fill NH4Cl solution; The second ion-selective working electrode (230) is used to fill the KCl solution; The reference electrode assembly (240) is used to fill the KCl solution.

3. The ammonium ion selective electrode according to claim 1, characterized in that: The first ion-selective working electrode (220) also includes a first reference electrode (223), which is disposed at the end plug (222) of the first working electrode. The second ion-selective working electrode (230) also includes a second reference electrode (233), which is inserted through the end cap (232) of the second working electrode. The reference electrode assembly (240) further includes a third reference electrode (244), which is inserted through the end cap (243) of the reference electrode.

4. The ammonium ion selective electrode according to claim 3, characterized in that: The first ion-selective working electrode (220) further includes a first front end cap (224), which is sleeved on the first working electrode tube body (221).

5. The ammonium ion selective electrode according to claim 4, characterized in that: The second ion-selective working electrode (230) also includes a second front end cap (234), which is sleeved on the second working electrode tube body (231).

6. The ammonium ion selective electrode according to claim 5, characterized in that: The first working electrode tube body (221) includes a first connecting tube body (2211) and a second connecting tube body (2212) connected in sequence. The first connecting tube (2211) is inserted into the front end cap (260); The first front end cap (224) is sleeved on the first connecting tube body (2211), and a first ion-selective membrane (225) is provided between the first front end cap (224) and the first connecting tube body (2211). And / or, The second working electrode tube (231) includes a third connecting tube (2311) and a fourth connecting tube (2312) connected in sequence. The third connecting tube (2311) is inserted into the front end cap (260). The second front end cap (234) is sleeved on the third connecting tube (2311), and a second ion-selective membrane (235) is provided between the second front end cap (234) and the third connecting tube (2311).

7. The ammonium ion selective electrode according to claim 6, characterized in that: The front end cap (260) is connected to a filter component (300). The filter element (300) is provided with a filter screen and a vibration assembly (321).

8. The ammonium ion selective electrode according to claim 7, characterized in that: The filter component (300) includes a filter cylinder (310) and a protective tail cap (320). A filter screen is provided on the filter cylinder (310); A vibration assembly (321) is provided inside the protective tail cap (320).

9. The ammonium ion selective electrode according to claim 8, characterized in that: The electrode body (200) also includes a fixing cover plate (250); The fixed cover plate (250) is connected to the electrode body shell (210); The fixed cover plate (250) is provided with through holes for fixing the first ion-selective working electrode (220), the second ion-selective working electrode (230), and the reference electrode assembly (240).

10. The ammonium ion selective electrode according to claim 6, characterized in that: A circuit board (110) is provided inside the electrode tail end (100). The first reference electrode (223), the second reference electrode (233), and the third reference electrode (244) are connected to the circuit board (110).

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