Novel combustion tube for combustion on-line ion chromatograph

Abstract

The utility model discloses a novel combustion tube for a combustion on-line ion chromatograph. The combustion tube comprises an inner tube and an outer tube which are arranged in a sleeving manner, the first end of the outer pipe is sealed on the outer wall surface of the inner pipe, the second end of the outer pipe is communicated with a conical outlet, an interlayer cavity formed by the outer pipe and the inner pipe is communicated with a second inlet, and oxygen can enter from the second inlet to support combustion or discharge residual gas; the first end of the inner tube is communicated with the sample boat chamber, and the second end of the inner tube extends into the outer tube; a sand core is fixedly arranged in the portion, between the second end of the inner pipe and the second end of the outer pipe, of the outer pipe, and the sand core enables combusted gas to continue to be diffused outwards and intercepts solid particles. A sample can enter the inner pipe from the sample boat chamber and is preheated and combusted, a first inlet is further communicated with the position close to the first end of the inner pipe, and the first inlet is designed in the mode that inert gas carrying ultrapure water is horizontally blown into the inner pipe through the first inlet. The ion chromatography detection device is reasonable in structure and exquisite in design, and can greatly improve the accuracy of ion chromatography detection data.

Description

Technical Field

[0001] The utility model relates to the technical field of sample detection, in particular to a novel combustion tube for an online combustion ion chromatograph. Background Art

[0002] The analysis of elemental content in samples is involved in many fields such as mineral resources, metallurgical engineering, environmental science, and food safety. Ion chromatograph is the most commonly used instrument for elemental content analysis and determination. In the process of using ion chromatograph to determine the elemental content of samples, high-temperature pyrolysis pretreatment of samples has been a method of elemental analysis pretreatment that has attracted much attention in recent years. This method combines the characteristics of high-temperature pyrolysis and water distillation. High-temperature pyrolysis mainly utilizes the volatility of some elements (such as halogens) to release them from their salts or other compounds in the form of vapor at high temperatures (such as 1100°C), and then absorbs the vapor in a suitable absorption liquid to achieve separation and enrichment of the components to be measured. In the prior art, in order to accurately and quickly determine the elemental content in samples, high-temperature pyrolysis pretreatment of samples is generally carried out in a high-temperature combustion tube of the detection equipment. It usually goes through preheating, heating, coking and combustion stages. While heating, ultrapure water, oxygen, etc. are filled into the combustion tube to carry out sample pyrolysis reaction.

[0003] The combustion tube is a key component. It passes through a combustion furnace, generating high temperatures within the tube, which then undergoes a cracking reaction. Ideally, the organic matter in the sample reacts with oxygen to produce water and carbon dioxide. Halogen groups such as chlorine, bromine, and fluorine, attached to the organic backbone, combine with hydrogen radicals generated by ultrapure water at high temperatures to form acidic free gases such as hydrogen chloride, hydrogen fluoride, and hydrogen bromide. These gases are easily soluble in the absorption liquid, ensuring that the halogens to be measured are fully detected. However, in production practice, the problem of residual hydrogen radicals after combustion often occurs, resulting in generally higher concentrations of acidic free gases in the experiments. This makes this elemental analysis pretreatment method less accurate than other treatment methods when tested by ion chromatography. Utility Model Content

[0004] This utility model discloses a new combustion tube for an online combustion ion chromatograph, which solves the technical problem of low ion detection data accuracy in existing combustion tubes. It has a reasonable structure, sophisticated design, and can greatly improve the accuracy of ion chromatography detection data. The technical solution adopted is as follows:

[0005] A novel combustion tube for an online combustion ion chromatograph, the combustion tube passing through a combustion furnace and comprising an inner tube and an outer tube arranged in a sleeve manner;

[0006] The first end of the outer tube is sealed on the outer wall of the inner tube, the second end of the outer tube is connected to a tapered outlet, and the interlayer cavity formed by the outer tube and the inner tube is connected to a second inlet, and oxygen can enter through the second inlet to assist combustion or discharge residual gas;

[0007] The first end of the inner tube is in communication with the sample boat chamber, and the second end of the inner tube extends into the outer tube;

[0008] A sand core is fixed in the outer tube between the second end of the inner tube and the second end of the outer tube, and the sand core includes a plurality of filter holes, and the filter holes are designed to allow the combusted gas to continue to diffuse outward and intercept solid particles;

[0009] The sample boat carrying the sample can enter the inner tube from the sample boat chamber and be preheated and burned. A first inlet is also connected near the first end of the inner tube. The first inlet is designed so that inert gas carrying ultrapure water is blown horizontally into the inner tube through the first inlet.

[0010] Based on the above technical solution, the sample is dropped from the dropping hole on the sample boat chamber into the sample boat therein. The sample boat chamber is also connected to a guide tube, which is provided with a third inlet. Inert gas or oxygen can be blown into the inner tube from the third inlet to discharge residual gas or aid combustion.

[0011] On the basis of the above technical solution, it also includes a capillary tube, wherein both ends of the capillary tube are arranged near the first end of the inner tube, one end of the capillary tube forms a first inlet, and the other end of the capillary tube passes through the outer tube and extends outside the outer tube. The capillary tube is coiled in the interlayer cavity to vaporize the ultrapure water blown in through the first inlet.

[0012] Based on the above technical solution, the capillary segment in the interlayer cavity includes a first length segment and a third length segment respectively arranged on both sides of the inner tube, and the first length segment and the third length segment are connected through an arc segment surrounding the second end of the inner tube.

[0013] On the basis of the above technical solution, a recoil pipe is fixedly provided on the conical surface forming the conical outlet. The end of the recoil pipe axially passes through the sand core and can provide recoil oxygen to the second end of the inner tube to assist combustion.

[0014] Based on the above technical solution, the recoil pipe includes an extended pipe section and an outlet pipe section, wherein the extended pipe section is coaxial with the outer pipe to reduce the disturbance of the airflow in the outer pipe, and an outlet is formed at the end of the outlet pipe section, and the outlet faces the inner wall of the outer pipe.

[0015] Based on the above technical solution, the inert gas is argon.

[0016] On the basis of the above technical solution, the combustion furnace is designed to make the temperature value in the combustion tube gradually increase from the first end of the inner tube to the second end of the inner tube.

[0017] Based on the above technical solution, the combustion furnace is designed to form multiple temperature zones along the axial direction of the inner tube, and the temperature values of the multiple temperature zones gradually increase from the first end of the inner tube to the second end of the inner tube, so that when the sample stays in each temperature zone for a set time, the heating or combustion state of the sample is controlled.

[0018] Beneficial effects

[0019] The utility model has an ingenious structural design. Inert gas carries ultrapure water and is blown horizontally into the inner tube through the first inlet. In this way, the ultrapure water can diffuse in a roughly directional direction in the inner tube, so that it can fully contact with the sample, thereby promoting the high-temperature cracking reaction; thereby avoiding the ultrapure water from diffusing back toward the sample boat chamber and condensing on the tube wall due to the diffusion effect. The sample boat that returns to the sample boat chamber still has a relatively high temperature, which can easily cause the ultrapure water condensed in the sample boat chamber to vaporize. On the one hand, this is not conducive to the full cracking reaction of the sample in this combustion. On the other hand, the vaporized ultrapure water can easily be swept forward and carried, causing the experimental data measured after the subsequent combustion reaction to deviate from the actual value, and the detection accuracy and stability are poor.

[0020] The present application also includes a sand core, through which cracked gas generated by sample combustion can be discharged outward, and incompletely burned solid particles are intercepted to allow them to burn again and fully release ions. The sand core can also prevent solid particles from entering the absorption liquid with the airflow, and can also prevent them from adhering to the combustion tube or the pipe connected thereto, which is beneficial to improving the service life of the device. In addition, a recoil tube passes through the sand core and its outlet faces the inner wall of the outer tube, so that oxygen can be added, which is beneficial to the complete combustion of the sample. In addition, the oxygen introduced by the recoil tube forms turbulent gas between the second end of the inner tube and the sand core, causing the solid particles intercepted on the surface of the sand core to tumble with the airflow, which can quickly cause the solid particles to burn again, avoiding the solid particles from being deposited on the surface of the sand core and incomplete combustion.

[0021] In this application, the third inlet can switch the blown inert gas to oxygen before the sample cokes or burns according to the combustion characteristics of different samples, further improving the combustion completeness, being flexible to use, and further contributing to improving the detection accuracy.

[0022] In the present application, both ends of the capillary are arranged close to the first end of the inner tube, and the temperature at the first end of the inner tube is reasonable. On the one hand, the inert gas can carry the atomized ultrapure water into the capillary, which is conducive to ensuring the stability of the airflow at the inlet of the capillary. On the other hand, the ultrapure water entering through the first inlet can go through the stages from preheating to combustion, which is conducive to ensuring that the ultrapure water is fully vaporized and fully cracked. In addition, the capillary is coiled in the interlayer cavity, which can preheat the ultrapure water before entering the inner tube, avoiding a sudden drop in temperature when the ultrapure water enters the inner tube, which is conducive to ensuring stable temperature conditions in the inner tube. In addition, the capillary includes two axially extending first length segments and third length segments, and the first length segment and the third length segment are connected by an arc segment. In this way, on the one hand, the ultrapure water can be effectively preheated, and on the other hand, the production and installation process of the capillary can be simplified, which is conducive to reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other implementation drawings can be derived from the provided drawings without inventive effort.

[0024] Figure 1 : Under the same combustion conditions, the scheme of the present invention (corresponding to the new tube data) and the first inlet perpendicular to the inner tube axis (corresponding to the old tube data) are used, and the measured fluoride and chloride ion chromatogram data are shown;

[0025] Figure 2 : Schematic diagram of the three-dimensional structure of the present invention;

[0026] Figure 3 : A schematic diagram of the cross-sectional structure of the side view of the present invention;

[0027] Figure 4 : Figure 3 Schematic diagram of the three-dimensional structure of the combustion tube; DETAILED DESCRIPTION

[0028] The following description and accompanying drawings sufficiently illustrate the specific embodiments herein to enable those skilled in the art to practice them. Portions and features of some embodiments may be included in or substituted for portions and features of other embodiments. The scope of the embodiments herein includes the entire scope of the claims, including all available equivalents thereof. Herein, the terms "first," "second," and the like are used solely to distinguish one element from another and do not require or imply any actual relationship or order between these elements. In practice, the first element can also be referred to as the second element, and vice versa. Furthermore, the terms "comprise," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a structure, device, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such structure, device, or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of other identical elements in the structure, device, or apparatus comprising the element. The various embodiments herein are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Similar or identical parts between the various embodiments can be referenced to each other.

[0029] The terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used herein to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are intended only to facilitate the description of this document and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In the description herein, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, they can be mechanical or electrical connections, or they can be internal connections between two elements, they can be directly connected, or they can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0030] As used herein, unless otherwise specified, the term "plurality" means two or more.

[0031] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0032] In this article, the term "and / or" is used to describe the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0033] like Figures 2-4The combustion tube shown is a novel combustion online ion chromatograph, which passes through a combustion furnace and includes an inner tube 1 and an outer tube 2 which are arranged in a sleeve manner.

[0034] The first end of the outer tube 2 is sealed on the outer wall of the inner tube 1, and the second end of the outer tube 2 is connected to a tapered outlet 21, which is connected to the absorption tube through a U-shaped tube. The U-shaped tube uses air cooling to cool the high-temperature cracking gas flowing through it. The absorption tube is filled with absorption liquid, such as ultrapure water absorption liquid, alkaline absorption liquid, etc.

[0035] like Figure 3 As shown, the interlayer cavity formed by the outer tube 2 and the inner tube 1 is connected to a second inlet 22, and oxygen can enter from the second inlet 22 to assist combustion or force residual gas to be discharged outward;

[0036] like Figure 3 As shown, the first end of the inner tube 1 is connected to the sample boat chamber 3. The sample is dropped from a drop hole in the sample boat chamber 3 into the sample boat therein. The sample boat chamber 3 is also connected to a guide tube with a third inlet 6. Inert gas or oxygen can be blown into the inner tube 1 through the third inlet 6 to expel residual gas or aid combustion. In this embodiment, argon is used as the inert gas. The second end of the inner tube 1 extends into the outer tube 2. The sample boat carrying the sample can enter the inner tube 1 from the sample boat chamber 3 for preheating and combustion.

[0037] like Figure 4 As shown, a sand core 7 is fixed in the outer tube 2 between the second ends of the inner tube 1 and the outer tube 2. The sand core 7 is provided with a plurality of axial filter holes, which are designed to allow the combusted gas to continue to diffuse outward and intercept solid particles.

[0038] The sample boat carrying the sample can enter the inner tube 1 from the sample boat chamber 3 and be preheated and burned. A first inlet 4 is also connected near the first end of the inner tube 1. The first inlet 4 is designed so that inert gas carrying ultrapure water is blown horizontally into the inner tube through the first inlet 4. Specifically, it also includes a capillary 5, such as Figure 3 and 4 As shown, one end of capillary tube 5 passes through the wall of inner tube 1 and extends into inner tube 1 to form first inlet 4. The other end of capillary tube 5 passes through outer tube 2 and extends outside of outer tube 2. Both ends of capillary tube 5 are located near the first end of inner tube 1. The outlet of first inlet 4 is axially arranged horizontally, and the capillary section forming first inlet 4 is close to the inner wall of inner tube 1, avoiding the sample boat. The design is reasonable, simple and ingenious.

[0039] In the present application, the first inlet 4 can make the ultrapure water diffuse in the inner tube 1 in a roughly directional direction, so that it can fully contact with the sample, thereby promoting the high-temperature cracking reaction, and avoiding the ultrapure water from diffusing back toward the sample boat chamber 3 due to the diffusion effect. Since the sample boat returning to the sample boat chamber 3 still has a relatively high temperature, it is very easy to cause the ultrapure water condensed in the sample boat chamber 3 to vaporize. In this way, on the one hand, when the amount of ultrapure water introduced is constant, the ultrapure water lost in the reflux is not easy to be quantitatively measured, and it is also not conducive to the full cracking reaction of the sample in this combustion. On the other hand, the vaporized ultrapure water is also very easy to be swept forward and carried, causing the experimental data measured after the subsequent combustion reaction to deviate from the actual value. Figure 1 As shown, the fluoride ion and chloride ion chromatographic data curves measured by adopting the solution of the present application, that is, inert gas carrying ultrapure water is blown horizontally into the inner tube (corresponding to the new tube data), are compared with the fluoride ion and chloride ion chromatographic data curves measured when the first inlet 4 is set perpendicular to the axis of the inner tube 1 (corresponding to the old tube data). It can be seen that the data measured in the solution of the present application is generally lower than the data measured when the first inlet 4 is set perpendicular to the axis of the inner tube 1, and is closer to the actual detection data; that is, the solution of the present application can well solve the technical problem of the generally high concentration of free acid gas in the detection of existing combustion tubes, which is conducive to improving the detection accuracy and improving the stability of the detection results.

[0040] like Figure 3 and 4 As shown, capillary tube 5 is coiled within the interlayer cavity to vaporize ultrapure water blown in through first inlet 4. Specifically, both ends of capillary tube 5 are located near the first end of inner tube 1. Capillary tube section 5 within the interlayer cavity includes a first length segment and a third length segment, located on either side of inner tube 1. The first and third length segments are connected by an arc-shaped segment surrounding the second end of inner tube 1. This preheats the ultrapure water before it enters inner tube 1, preventing a sudden temperature drop upon entry and helping to maintain stable temperature conditions within the inner tube.

[0041] like Figure 3 As shown, the first end of the inner tube 1 is connected to the sample boat chamber 3, and the sample is dropped into the sample boat from the drop hole on the sample boat chamber 3. The sample boat chamber 3 is also connected to a guide tube, which is provided with a third inlet 6. Inert gas or oxygen can be blown into the inner tube 1 from the third inlet 6 to discharge residual gas or aid combustion.

[0042] The second end of the inner tube 1 extends into the outer tube 2 , and the sample boat carrying the sample can enter the inner tube 1 from the sample boat chamber 3 and be preheated and burned.

[0043] Among them, a recoil pipe 8 is fixedly provided on the conical surface forming the conical outlet 21. The end of the recoil pipe 8 axially passes through the sand core 7 and the outlet faces the inner wall of the outer tube 2. Oxygen can enter the outer tube 2 through the recoil pipe 8 to assist combustion. As shown in the figure, the recoil pipe 8 includes an extended pipe section and an outlet pipe section, wherein the extended pipe section is coaxial with the outer tube 2 to reduce the disturbance of the airflow in the outer tube 2. The end of the outlet pipe section forms an outlet, and the outlet faces the inner wall of the outer tube. The oxygen blown out from the outlet collides with the inner wall of the outer tube, causing disturbance of the surrounding airflow, which can vibrate the solid particles attached to the sand core 7, thereby promoting the re-combustion of the solid particles.

[0044] In the present application, the combustion furnace is designed so that a plurality of temperature zones are formed in the combustion tube, wherein the temperature values of the plurality of temperature zones gradually increase from the first end of the inner tube 1 to the second end of the inner tube 1. In the present embodiment, from the first end of the inner tube 1 to the second end of the inner tube 1, it can be roughly divided into a first heating zone, a second heating zone, a third heating zone and a highest temperature zone, and from the first heating zone to the highest temperature zone, the temperature in the inner tube first rises slowly and then rises rapidly to the highest temperature, and maintains the highest temperature in the highest temperature zone. Its temperature curve roughly conforms to the half-side curve of the normal distribution. In this way, on the one hand, it can be fully preheated, and on the other hand, the temperature in multiple temperature zones gradually increases to prevent the sample from directly entering the highest temperature zone and causing explosion.

[0045] In this way, when the sample boat stays in each temperature zone for a set time, the setting of multiple temperature zones facilitates more precise control of the sample heating or combustion state, allowing the sample to complete the preheating, heating, coking and combustion processes well. In addition, the sample boat stays in the highest temperature zone for the longest time, thus ensuring sufficient combustion.

[0046] Working process

[0047] First, the equipment is prepared; the pipes are connected, the equipment is initialized, and the combustion furnace is controlled so that the temperature in the inner tube 1 rises slowly from the first heating zone to the highest temperature zone in the combustion tube and then rises rapidly to the highest temperature, and the highest temperature is maintained in the highest temperature zone;

[0048] After that, the residual gas is removed, and the third inlet 6 is opened to blow an inert gas, such as argon, into the inner tube 1. At the same time, the second inlet 22 is opened to blow oxygen into the interlayer cavity, so that the inner tube 1 is filled with argon and the interlayer cavity is filled with oxygen.

[0049] Afterwards, the sample is preheated, and the sample boat carrying the sample begins to move from the first end of the inner tube 1 toward its second end. At this time, argon is still blown into the third inlet 6, and oxygen is still blown into the second inlet 22. Simultaneously, as the sample boat moves from the first end of the inner tube 1 toward the second end, the sample boat and the sample therein are preheated. As the sample boat carrying the sample begins to move from the first end of the inner tube 1 toward the second end, an inert gas, such as argon, carrying ultrapure water is blown horizontally into the inner tube 1 through the first inlet 4, and oxygen is introduced into the outer tube through the backflush tube 8.

[0050] The sample is then heated and burned, and the sample boat carries the sample from the first end of the inner tube 1 to the second end of the inner tube. The sample undergoes preheating, heating, coking and combustion stages, and finally the sample burns at the second end of the inner tube 1 to produce cracking gas; wherein, before the sample cokes or burns, the inert gas blown in by the third inlet 6 is switched to oxygen to ensure sufficient combustion.

[0051] The absorption liquid is then tested. Gases from sample combustion and decomposition are discharged through the outer tube's tapered outlet 21 and enter the absorption liquid. After sample combustion is complete, the flow of the argon and ultrapure water mixture through the first inlet 4 is stopped, and the sample boat returns to the sample boat chamber 3. Inert gas is continued to flow through the third inlet 6, and absorption of the absorption liquid is completed. The obtained absorption liquid is tested by the ion chromatograph detection module. Testing of the absorption liquid by the ion chromatograph detection module is conventional technology and will not be described in detail here.

[0052] This cycle is repeated to complete the combustion detection and analysis of multiple samples.

[0053] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments. Any changes or modifications based on the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A new type of combustion tube for online combustion ion chromatograph, characterized in that: The combustion tube passes through the combustion furnace and comprises an inner tube (1) and an outer tube (2) which are arranged in a sleeve manner; The first end of the outer tube (2) is sealed on the outer wall surface of the inner tube (1), the second end of the outer tube (2) is connected to a tapered outlet (21), and the interlayer cavity formed by the outer tube (2) and the inner tube (1) is connected to a second inlet (22), and oxygen can enter from the second inlet (22) to assist combustion or discharge residual gas; The first end of the inner tube (1) is in communication with the sample boat chamber (3), and the second end of the inner tube (1) extends into the outer tube (2); A sand core (7) is fixedly provided in the outer tube (2) between the second end of the inner tube (1) and the second end of the outer tube (2), wherein the sand core (7) comprises a plurality of filter holes, and the filter holes are designed so that the combusted gas continues to diffuse outward and intercepts solid particles; The sample boat carries the sample and can enter the inner tube (1) from the sample boat chamber (3) to be preheated and burned. A first inlet (4) is also connected near the first end of the inner tube (1). The first inlet (4) is designed so that inert gas carrying ultrapure water is blown horizontally into the inner tube (1) through the first inlet (4).

2. The novel combustion tube for online ion chromatograph according to claim 1, characterized in that: The sample is dropped from the drop hole on the sample boat chamber (3) into the sample boat therein. The sample boat chamber (3) is also connected to a guide tube, and a third inlet (6) is provided on the guide tube. Inert gas or oxygen can be blown into the inner tube (1) from the third inlet (6) to discharge residual gas or assist combustion.

3. The novel combustion tube for online combustion ion chromatograph according to claim 1 or 2, characterized in that: The invention also includes a capillary tube (5), both ends of which are arranged near the first end of the inner tube (1), one end of the capillary tube (5) forms a first inlet (4), and the other end of the capillary tube (5) passes through the outer tube (2) and extends outside the outer tube (2), and the capillary tube (5) is coiled in the interlayer cavity to vaporize the ultrapure water blown in through the first inlet (4).

4. The novel combustion tube for online combustion ion chromatograph according to claim 3, characterized in that: The capillary tube (5) section in the interlayer cavity comprises a first length section and a third length section respectively arranged on both sides of the inner tube (1); the first length section and the third length section are connected via an arc section surrounding the second end of the inner tube (1).

5. The novel combustion tube for online combustion ion chromatograph according to claim 3, characterized in that: A recoil pipe (8) is fixedly provided on the conical surface forming the conical outlet (21), and the end of the recoil pipe (8) axially passes through the sand core (7) and can provide recoil oxygen to the second end of the inner tube (1) to assist combustion.

6. The novel combustion tube for online combustion ion chromatograph according to claim 5, characterized in that: The recoil pipe (8) comprises an extended pipe section and an outlet pipe section, wherein the extended pipe section is coaxial with the outer pipe to reduce disturbance of the airflow in the outer pipe (2), and an outlet is formed at the end of the outlet pipe section, and the outlet faces the inner wall surface of the outer pipe (2).

7. The novel combustion tube for online combustion ion chromatograph according to claim 3, characterized in that: The inert gas is argon.

8. The novel combustion tube for online combustion ion chromatograph according to any one of claims 4 to 7, characterized in that: The combustion furnace is designed so that the temperature value in the combustion tube gradually increases from the first end of the inner tube (1) to the second end of the inner tube (1).

9. The novel combustion tube for online combustion ion chromatograph according to claim 8, characterized in that: The combustion furnace is designed to form a plurality of temperature zones along the axial direction of the inner tube (1), and the temperature values of the plurality of temperature zones gradually increase from the first end of the inner tube to the second end of the inner tube, so that when the sample stays in each temperature zone for a set period of time, the heating or combustion state of the sample is controlled.

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