Ion chromatograph-mass spectrometer combination calibrating device

Abstract

The present application relates to a kind of ion chromatography, mass spectrometer calibration device for combination, be arranged between suppressor outlet and mass spectrometer ion source entrance.The device includes the main body by inner core and shell, and annular sample cavity of containing calibration fluid is enclosed between the two.The inner core is internally provided with sample main flow channel, and its contraction part, throat and diffusion part constitute venturi structure;Throat is provided with the permeation window covered by semi-permeable membrane.The first electrode and the second electrode are respectively arranged on the inside and outside of semi-permeable membrane.Controller controls electrode to establish positive electric field when calibration, accelerates sample ion to pass through semi-permeable membrane and enter main flow channel;Reverse pulse electric field is established when calibration ends, and residual components on semi-permeable membrane are sucked back into annular sample cavity.Using venturi fluid dynamic pressure and electrode drive coupling, the precise addition of internal standard substance is realized without mechanical pulse, and phase lag and memory effect are completely eliminated, and the stability of system detection is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of instrumentation technology, and in particular to a calibration device for an ion chromatography-mass spectrometry system. Background Technology

[0002] Ion chromatography-mass spectrometry (IC-MS) is a key precision platform in the field of analytical chemistry for the qualitative and quantitative analysis of polar substances and inorganic and organic ions in complex matrix samples. Its core working process includes the physical spatial separation of mixed components by the ion chromatography column, the subsequent chemical suppression of the background conductivity of the eluent by the suppressor, and finally the real-time monitoring of the mass-charge ratio (m / z) of the target ion by the mass spectrometer as a high-sensitivity detector.

[0003] Because the electrospray ionization source of a mass spectrometer is highly susceptible to sensitivity drift caused by changes in the composition of the eluent, interference from complex sample matrices, and fluctuations in instrument vacuum, an internal standard calibration solution of known concentration is introduced into the flow path between the suppressor outlet and the mass spectrometer inlet to obtain accurate quantitative analysis results. By using the synchronous response ratio between the internal standard and the analyte during the ionization process, a follow-up mass reference system is formed to compensate for measurement errors caused by matrix suppression effects and hardware instability in real time.

[0004] The commonly used technology employs a three-way mixing connector combined with an external mechanical injection pump for forced injection. However, since the external injection pump essentially relies on a stepper motor to drive the piston in reciprocating motion, this mechanical drive mode inevitably generates periodic pulsating pressure. When this pulsed fluctuation flows through the three-way connector into the main eluent path, it directly disrupts the fluid balance of the Taylor cone within the mass spectrometer electrospray source, causing nonlinear flickering of the spray pattern. This is reflected in the detection terminal as periodic sawtooth-shaped background noise. This interference signal introduced by mechanical intervention not only severely reduces the instrument's signal-to-noise ratio but also easily overwhelms weak signal components during trace analysis, leading to a significant deterioration of the detection limit.

[0005] Furthermore, the geometrical dead volume within the three-way mixing connector and the low-laminar flow characteristics of the fluid at the confluence point mean that the internal standard component needs to undergo a relatively long physical journey after entering the main flow path to achieve radial uniform distribution. This process often induces significant peak broadening and signal tailing, severely weakening the separation efficiency of the ion chromatography column for adjacent components. This makes it difficult for the internal standard and analyte to achieve an ideal synergistic effect, ultimately making it difficult for real-time correction of matrix suppression effects to meet the stringent requirements of high-precision quantitative detection. Summary of the Invention

[0006] The purpose of this invention is to provide a calibration device for an ion chromatography-mass spectrometry instrument, which solves the technical problems of pulsed background noise interference introduced by the forced drive of a mechanical pump and peak broadening and signal tailing caused by dead volume in the flow path.

[0007] The technical solution of the ion chromatography-mass spectrometry calibration device of the present invention is as follows:

[0008] An ion chromatography-mass spectrometry calibration device is installed in the analytical flow path between the suppressor outlet of the ion chromatograph and the ion source inlet of the mass spectrometer. The device includes:

[0009] The main body includes an inner core and a shell fitted around the outer periphery of the inner core. The shell has a standard sample inlet at the upstream end of the fluid and a standard sample outlet at the downstream end of the fluid.

[0010] The annular standard sample chamber is formed by the annular cavity enclosed by the inner wall of the shell and the outer wall of the inner core, and is used to contain the calibration fluid.

[0011] The main sample channel runs through the interior of the core and includes a constriction section, a throat, and a diffuser section that are connected sequentially along the fluid direction. The inner diameter of the throat is smaller than the inner diameter of the constriction section and the diffuser section, thus forming a Venturi structure. The throat is provided with a permeation window that connects the inside and outside.

[0012] A semi-permeable membrane, covering the permeation window;

[0013] The first electrode and the second electrode are respectively disposed on the inner and outer sides of the semipermeable membrane to establish a transmembrane driving electric field on both sides of the semipermeable membrane.

[0014] The controller is connected to the first and second electrodes to establish a positive electric field between the first and second electrodes during the calibration process, thereby accelerating the standard ions through the semipermeable membrane; and at the end of the calibration period, it controls the first and second electrodes to establish a reverse pulsed electric field to draw the residual components on the semipermeable membrane into the annular standard chamber.

[0015] Furthermore, an annular window is provided on the wall surface of the inner core corresponding to the throat, and a support grid with several micropores is provided inside the annular window, with the semi-permeable membrane covering the outer periphery of the support grid.

[0016] Furthermore, the first electrode is disposed on the support grid, and the second electrode is disposed on the inner wall surface of the housing, radially outward corresponding to the first electrode.

[0017] Furthermore, the inner core has stepped portions at both ends, and plugs are filled between the stepped portions and the inner wall of the shell, with sealing rings provided between the plugs, the shell, and the stepped portions.

[0018] Furthermore, the inner core includes a core body and locking nuts screwed opposite each other from the center of the core body to both ends of the core body, and the end of the semi-permeable membrane is clamped between the locking nuts and the end of the core body.

[0019] Furthermore, the standard sample inlet is connected to a standard sample selection valve, which is connected to different standard substance storage bottles through multiple branches.

[0020] Furthermore, the main body is equipped with a front-end sensor at the front end and a mass spectrometry switching valve at the rear end. The output port of the mass spectrometry switching valve is connected to the ion source inlet of the mass spectrometer and the waste liquid tank, respectively. The front-end sensor is located upstream of the main sample channel, and the mass spectrometry switching valve is used to switch the connection state between the main sample channel and the mass spectrometer or the waste liquid tank. The controller is signal-connected to the front-end sensor, the first electrode and the second electrode, the standard selection valve and the mass spectrometry switching valve.

[0021] Furthermore, the upstream and downstream sides of the main body are equipped with switching tees, and the two switching tees are short-connected by a pipeline so that the main fluid can bypass the main body and be directly introduced into the mass spectrometer.

[0022] The beneficial effects of this application are as follows: Compared with the prior art, the ion chromatography-mass spectrometry calibration device provided by this invention introduces a calibration device at a specific flow path node between the ion chromatograph suppressor outlet and the mass spectrometer ion source inlet. Utilizing a Venturi structure formed by a constriction, throat, and diffusion section sequentially connected within the sample main channel, when the separated and background-suppressed eluent flows at high speed through the throat narrowing region, according to Bernoulli's principle, the increase in fluid dynamic pressure induces a local instantaneous static pressure drop, thereby constructing a spontaneous inward pressure gradient across the semi-permeable membrane. This allows internal standard ions to smoothly enter the main fluid via permeation, eliminating the severe interference on the stability of mass spectrometry electrospray ionization caused by the periodic pulsations generated by the external mechanical pump stepper motor in the prior art. The injection method based on dynamic pressure balance greatly reduces the background noise of the mass spectrometry baseline, ensuring accurate detection of trace components in an environment with extremely high signal-to-noise ratio.

[0023] Furthermore, during the calibration process, the positive electric field established by the controller applies a directional Lorentz force to the calibration ions, increasing their transmembrane migration rate from simple passive diffusion to an accelerated migration state excited by the electric field. This reduces the response time required for the internal standard molecule to penetrate the semipermeable membrane, effectively eliminating the phase lag between the internal standard component and the sample peak when it enters the main flow path. This ensures that the internal standard and the analyte can achieve real-time, in-phase spatiotemporal superposition at the molecular level, thus providing a reliable reference for correcting complex matrix inhibition effects.

[0024] A reverse pulsed electric field is introduced at the moment the calibration period ends, effectively avoiding the inherent memory effect and cross-contamination risk of the permeable membrane. When calibration needs cease, the controller instantaneously reverses the voltage polarity between the first and second electrodes. The resulting reverse electrostatic suction force rapidly pulls the internal standard ions remaining in the pores and near the membrane surface back into the annular standard chamber. This, combined with the high shear force flow field at the Venturi throat, flushes away the microscopic retention layer. This allows for a rapid, abrupt cutoff of the internal standard signal, not only avoiding continuous background interference from calibration components to subsequent samples but also significantly reducing the system's switching time between different calibration modes. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a specific embodiment of the calibration device for an ion chromatography-mass spectrometry instrument of the present invention.

[0026] Figure 2 for Figure 1 A sectional view of the main body of the device;

[0027] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle.

[0028] In the picture:

[0029] 101-Eluent reservoir; 102-High-pressure eluent pump; 103-Injection valve; 104-Guard column; 105-Analytical column; 106-Suppressor; 107-Pre-sensor; 108-Mass spectrometer switching valve; 109-Mass spectrometer; 110-Waste container; 111-Internal standard reservoir; 112-Standard selection valve; 113-Switching tee; 114-Sample injection bottle;

[0030] 200 - Main body; 210 - Shell; 220 - Inner core; 221 - Stepped section; 230 - Sealing ring; 240 - Locking nut; 250 - Plug;

[0031] 310 - Sample main channel; 311 - Contraction section; 312 - Throat; 313 - Diffusion section; 320 - Permeation window; 321 - Support grid; 330 - Semi-permeable membrane; 340 - Annular standard sample chamber; 341 - Standard sample inlet; 342 - Standard sample outlet;

[0032] 410 - First electrode; 420 - Second electrode. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0036] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0037] Specific embodiments of the ion chromatography-mass spectrometry calibration device of the present invention are as follows: Figures 1 to 3As shown, this device is used in an ion chromatography-mass spectrometry (ICMMS) system. The ICMMS system is a high-end analytical platform integrating ion detection. Its fluid path begins at the eluent supply end. High-purity chemical eluents (such as potassium hydroxide, methanesulfonic acid, etc.) are stored in the eluent reservoir 101, with a constant flow rate provided by a high-pressure eluent pump 102. The system back pressure is typically maintained at 20 MPa to 40 MPa. The eluent then flows through the injection valve 103. Through the physical switching of the quantitative loop within the injection valve 103, the sample is injected through the sample injection vial 114, carrying the collected sample components into the chromatographic flow path in a plug-like manner. The sample fluid first enters the guard column 104 and the ion analysis column 105. In the stationary phase filled with ion exchange resin, based on the slight differences in the Coulomb affinity between different analyte ions and the functional groups of the stationary phase, the components achieve spatial and temporal separation during elution.

[0038] The separated eluent enters the electro-regenerative suppressor 106. As a key conversion node at the ion chromatography end, the suppressor 106 uses the selective permeation of the ion exchange membrane to convert the strong electrolyte components in the eluent into low-conductivity pure water or a very weak acid-base environment, thereby significantly reducing background noise and improving the response sensitivity of the analyte ions. At this point, the suppressed fluid is in a pure state with extremely low background conductivity, which provides an ideal physical background for subsequent mass spectrometry detection, but also imposes stringent hydrodynamic stability requirements on any additional calibration components introduced.

[0039] This device is located in the critical flow channel between the outlet of the suppressor 106 and the inlet of the ion source of the mass spectrometer 109. When the eluent flows through this device, its physical phase remains in the high-pressure liquid phase. After entering the electrospray ionization source of the mass spectrometer 109, it undergoes desolvation and ionization processes, transforming into gaseous ions that enter the mass analyzer. Since the ionization efficiency of the mass spectrometer 109 is highly dependent on the geometric stability of the Taylor cone and is easily affected by ionization suppression caused by eluent flow rate fluctuations or the sample matrix, this system establishes a real-time mass reference system by introducing a calibration component at a specific node after the suppressor 106. By continuously or pulsedly monitoring standard substances with known charge-to-mass ratios, the system can calculate the fluctuation in detection sensitivity at each moment in real time, thereby dynamically correcting the quantitative results of the sample components. This process ensures that the analytical data maintains extremely high repeatability and qualitative accuracy even in complex matrix environments.

[0040] Specifically, the device includes a main body 200, which consists of an inner core 220 and a shell 210 fitted around the inner core 220. The shell 210 can be made of PEEK material or high-performance ceramic. The outer wall of the shell 210 has a standardized cylindrical structure. A main sample channel 310 runs through the center of the inner core 220. The main sample channel 310 has a Venturi cross-section within the shell 210, connecting from upstream to downstream a contraction section 311, a throat 312, and a diffuser 313. The inner diameter of the throat 312 is precisely limited to approximately 0.1 mm, significantly smaller than the flow cross-sectional area of ​​the contraction section 311 and the diffuser 313. When the eluent flows through the throat 312, the sudden increase in flow velocity causes a static pressure drop, creating a localized micro-negative pressure effect on the throat 312 wall. To utilize this physical effect, a permeation window 320, a ring-shaped window, is formed on the wall of the throat 312 using micromachining technology, and is covered with a semi-permeable membrane 330. The semi-permeable membrane 330 is made of a polymer material with high ion selectivity and is tightly attached to the outside of the permeation window 320 through a combination of physical coating and chemical bonding, completely isolating the inner sample main channel 310 from the outer annular standard chamber 340. For example, a perfluorosulfonic acid proton exchange membrane, with its unique water channel structure and sulfonic acid group active sites, can exhibit extremely high ion mobility under an electric field.

[0041] To cope with the high-pressure load of the eluent, the inner core 220 is specially equipped with a support grid 321 in the permeation window 320 area corresponding to the throat 312. This support grid 321 has a highly porous microporous mesh structure and is located between the main sample channel 310 and the semi-permeable membrane 330. The presence of the support grid 321 not only provides rigid support for the flexible semi-permeable membrane 330, preventing it from being squeezed, deformed, or ruptured into the channel under high pressure, but also guides the uniform distribution of electric field lines through its uniformly distributed micropores. The semi-permeable membrane 330 is fitted around the outer periphery of the support grid 321, and its axial ends are positioned by steps 221 provided on the inner core 220. An insulating plug 250 is filled between the step 221 and the inner wall of the housing 210, and radial compression sealing is achieved at the contact surface by an O-ring 230. This multi-layered sealing structure ensures relative isolation between the high-pressure sample flow and the external standard solution, and all material exchange can only be achieved through molecular-level permeation of the semi-permeable membrane 330.

[0042] Furthermore, the mechanical assembly of the inner core 220 adopts a modular screwing logic. The inner core 220 includes a core body and locking nuts 240 that are screwed back to both ends from the center of the core body. During assembly, the end of the semi-permeable membrane 330 is physically clamped between the locking nut 240 and the end of the core body. This axial clamping force and radial sealing force together constitute the pressure boundary of the device. The semi-permeable membrane 330 can be quickly replaced or cleaned by simply unscrewing the locking nut 240.

[0043] An annular standard sample cavity 340, formed by the inner wall of the housing 210 and the outer wall of the inner core 220, is used to continuously contain and replenish the calibration fluid. To optimize the electric drive efficiency and reduce the influence of dead volume, the inner wall of the housing 210 adopts a fitting design with a recessed portion towards the central axis. This design causes the radial width of the annular standard sample cavity 340 to increase by a specific amount in the axial region corresponding to the throat 312, while at both ends of the device, the inner wall of the housing 210 and the outer wall of the inner core 220 form a narrow gap that fits tightly. The wide cavity region in the middle acts as a reservoir for internal standard ions, ensuring that the ion concentration at the membrane interface does not change due to instantaneous consumption during high-current driven permeation; while the narrow gaps at both ends provide fluid damping and mechanical guidance, achieving efficient chamber isolation in conjunction with the sealing ring 230.

[0044] The main body 200 also includes an electrically driven assembly, specifically a first electrode 410 and a second electrode 420. The first electrode 410 is disposed on the support grid 321 and contacts the inner side of the semi-permeable membrane 330; the second electrode 420 is disposed at the corresponding position on the recessed surface of the inner wall of the housing 210, that is, the radially outermost part of the annular sample cavity 340. Both the first electrode 410 and the second electrode 420 can be made of platinum. The support grid 321 is preferably made of titanium alloy or carbon fiber reinforced PEEK material, and the first electrode can be attached to the surface of the support grid 321 by means of adhesion or electroplating.

[0045] By applying an electrical signal between the two electrodes through the controller, the system can establish a transient, high-intensity transmembrane driving electric field across the semipermeable membrane 330. This field-coupled control changes the logic of traditional pump-mixing, transforming the loading process of the calibration material from an unstable pressure-driven process to a precisely quantifiable charge-driven process, greatly suppressing baseline pulse-like movements and improving the stability of detection accuracy.

[0046] The overall control of the system is executed by the controller, whose signal transmission path includes the pre-sensor 107 located at the front end of the main body 200, the electric drive assembly, the standard sample selection valve 112 located in the external flow path, and the mass spectrometry switching valve 108 located at the end of the device. The output port of the mass spectrometry switching valve 108 is connected to the ion source inlet of the mass spectrometer 109 and the waste liquid tank 110, respectively; the pre-sensor 107 is located upstream of the sample main flow channel 310, and the mass spectrometry switching valve 108 is used to switch the connection status of the sample main flow channel 310 with the mass spectrometer 109 or the waste liquid tank 110.

[0047] When the sample components separated from the ion chromatography column flow with the eluent to the mass spectrometer 109, the pre-sensor 107 first captures the initial signal of the sample peak arrival. The controller calculates the precise time when the components reach the Venturi throat 312 and, within a preset lead time, drives the electrode to establish a positive driving electric field. At this time, the internal standard ions are accelerated across the membrane by the electric field force, and they intersect with the sample peak precisely in the throat 312 region. Due to the extremely narrow cross-sectional area of ​​the throat 312, an extremely high flow rate is generated, and the internal standard molecules are instantaneously entrained into the center of the fluid, achieving uniform mixing. This process solves the phase lag problem caused by the hysteresis of the permeation reaction through feedforward control, ensuring that the internal standard signal and the sample signal resonate at the same frequency within the mass spectrometry ion source.

[0048] At the very end of each calibration period (i.e., the sample peak elution period), the controller immediately executes a reverse pulse command. By reversing the electrode voltage polarity, a reverse electrostatic pull is established. Since the high-velocity shearing action at the Venturi throat 312 has already carried away most of the components from the membrane surface, the reverse electric field is responsible for drawing back ions remaining in the micropores of the semi-permeable membrane 330 and the gaps in the support grid 321 to the external annular standard chamber 340. This active suction mechanism empties the sample inlet channel within milliseconds, completely eliminating the memory effect and signal tailing phenomenon commonly found in permeable membranes, allowing the mass spectrometry background to quickly recover to baseline levels and eliminating cross-contamination for subsequent sample analysis.

[0049] As an extremely precise detection terminal highly sensitive to background ions, the signal-to-noise ratio of the Mass Spectrometer 109 directly determines the detection limit for ultra-trace components. If the internal standard component remains injected throughout a chromatographic run lasting tens of minutes, a continuously rising and significantly fluctuating chemical background noise layer will form in the total ion chromatogram of the mass spectrometer detector. This artificially introduced "background signal cloud" will produce a severe masking effect when processing weak sample peaks on the order of ppt, causing the effective signal of the target component to be submerged in the background fluctuations. However, by exciting the transmembrane electric field only within a specific time window of sample peak effervescence, the internal standard component can instantaneously merge with the sample component only when necessary, thus maintaining an extremely clean baseline background for most of the time in the non-peak region. This active suppression of background noise greatly improves the system's detection sensitivity for complex matrix samples.

[0050] Furthermore, if internal standard ions continuously occupy the ion source space in large quantities, it will not only waste ionization energy but may also have a secondary inhibitory effect on other trace components under certain matrix conditions. Meanwhile, considering that the standard solutions used in ion chromatography often contain a certain mass concentration of isotope labels or inorganic salts, prolonged and continuous ion bombardment will significantly accelerate the fouling rate of the cone pores and ion lens components inside the mass spectrometer ion source and shorten the physical effective lifespan of the electron multiplier tube detector.

[0051] Pulsed injection via an electrically driven component allows for precise control of the internal standard injection volume within the microsecond range of sample peak effluent. This significantly reduces the economic cost of expensive standard solutions and avoids the risk of detector dynamic range saturation due to internal standard overload. It retains the real-time calibration accuracy of the internal standard method for matrix inhibition while providing the system with higher hardware stability.

[0052] The side wall of the housing 210 has a standard inlet 341 upstream of the fluid and a standard outlet 342 downstream of the fluid. The standard inlet 341 is connected to multiple branches through a standard selection valve 112, which can automatically switch the standard substance in the internal standard storage bottle 111 according to different analytical items (such as anion calibration, cation calibration, or organic mass-to-charge ratio calibration). The switching tee 113 and pipeline short-circuiting structure provided upstream and downstream of the main body 200 allow the main eluent fluid to bypass the main body 200 and enter the mass spectrometer 109 directly under non-calibration conditions.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. A calibration device for an ion chromatography-mass spectrometry system, characterized in that, The device is disposed in the analytical flow path between the suppressor outlet of the ion chromatograph and the ion source inlet of the mass spectrometer, and the device includes: The main body includes an inner core and a shell fitted around the outer periphery of the inner core. The shell has a standard sample inlet at the upstream end of the fluid and a standard sample outlet at the downstream end of the fluid. The annular standard sample chamber is formed by the annular cavity enclosed by the inner wall of the shell and the outer wall of the inner core, and is used to contain calibration fluid. The main sample channel runs through the interior of the core and includes a constriction section, a throat, and a diffuser section that are connected sequentially along the fluid direction. The inner diameter of the throat is smaller than the inner diameter of the constriction section and the diffuser section, thus forming a Venturi structure. The throat is provided with a permeation window that connects the inside and outside. A semi-permeable membrane, covering the permeation window; The first electrode and the second electrode are respectively disposed on the inner and outer sides of the semipermeable membrane to establish a transmembrane driving electric field on both sides of the semipermeable membrane. The controller is connected to the first and second electrodes to establish a positive electric field between the first and second electrodes during the calibration process, thereby accelerating the standard ions through the semipermeable membrane; and at the end of the calibration period, it controls the first and second electrodes to establish a reverse pulsed electric field to draw the residual components on the semipermeable membrane into the annular standard chamber.

2. The calibration device for an ion chromatography-mass spectrometry system according to claim 1, characterized in that, The inner core has an annular window on the wall surface corresponding to the throat, and the annular window has a support grid with a plurality of micropores inside, and the semi-permeable membrane covers the outer periphery of the support grid.

3. The calibration device for an ion chromatography-mass spectrometry system according to claim 2, characterized in that, The first electrode is disposed on the support grid, and the second electrode is disposed on the inner wall surface of the housing, corresponding to the radial outer side of the first electrode.

4. The calibration device for an ion chromatography-mass spectrometry system according to claim 1, characterized in that, The inner core has stepped portions at both ends, and plugs are filled between the stepped portions and the inner wall of the shell. A sealing ring is provided between the plugs, the shell, and the stepped portions.

5. The calibration device for an ion chromatography-mass spectrometry system according to claim 1, characterized in that, The inner core includes a core body and locking nuts screwed opposite each other from the center of the core body to both ends of the core body. The end of the semi-permeable membrane is clamped between the locking nuts and the end of the core body.

6. The calibration device for an ion chromatography-mass spectrometry system according to claim 1, characterized in that, The standard sample inlet is connected to a standard sample selection valve, which is connected to different standard substance storage bottles through multiple branches.

7. The calibration device for an ion chromatography-mass spectrometry system according to claim 6, characterized in that, The main body is equipped with a front sensor at the front end and a mass spectrometry switching valve at the rear end. The output port of the mass spectrometry switching valve is connected to the ion source inlet of the mass spectrometer and the waste liquid tank, respectively. The front sensor is located upstream of the main sample channel. The mass spectrometry switching valve is used to switch the connection state between the main sample channel and the mass spectrometer or the waste liquid tank. The controller is signal-connected to the front sensor, the first electrode and the second electrode, the standard selection valve and the mass spectrometry switching valve.

8. The calibration device for an ion chromatography-mass spectrometry system according to claim 1, characterized in that, The main body is equipped with switching tees on both the upstream and downstream sides. The two switching tees are short-connected by a pipeline so that the main fluid can bypass the main body and be directly introduced into the mass spectrometer.

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