Sample injection dechlorination device for mass spectrometry of soluble organic carbon isotope

Abstract

The utility model relates to a sample injection dechlorination device for mass spectrum determination of soluble organic carbon isotopes, which is used for removing chlorine in gas-phase sample injection and is characterized in that ports of upstream and downstream sections of a sample injection needle capillary tube which is disconnected in the middle are respectively and hermetically connected with upstream and downstream thickened reducing pipe connectors; and the thickened pipe ends of the upstream and downstream thickened variable-diameter pipe connecting pieces are jointly connected with a filter pipe in a sealing manner, wherein a plurality of axially parallel silver tow-shaped filter elements are arranged in the filter pipe. The upstream and downstream thickened reducing pipe connecting piece is composed of an internal thread pipe head seat in sealed connection with the upstream and downstream section end of the capillary pipe, an internal thread pipe base in sealed connection with the filter pipe end, and a reducing external thread pipe joint with the two ends in sealed threaded connection with internal thread pipe holes of the internal thread pipe head seat and the internal thread pipe base through corrosion-resistant elastic sealing rings respectively. The method has the advantage of being capable of removing chlorine in gas-phase sample introduction during mass spectrometry in a simple, reliable and feasible manner.

Description

Dechlorinator for soluble organic carbon isotope mass spectrometry Technical Field

[0001] This utility model relates to a sample processing device for isotope mass spectrometry, and particularly to a sample dechlorination device for soluble organic carbon isotope mass spectrometry. Background Technology

[0002] Our stable isotope mass spectrometry laboratory is capable of determining soluble organic carbon (DOC) carbon isotopes in general water bodies. In recent years, a project team has been conducting carbon source and sink analysis of lakes on the Qinghai-Tibet Plateau, requiring the determination of soluble organic carbon (DOC) carbon isotopes in the lake water. Water samples collected from Qinghai-Tibet Plateau lakes underwent pretreatment similar to other water samples. However, after testing just a few samples, the probe became clogged. Furthermore, small, pale green water droplets appeared at the probe's insertion point on the sample pad, which was unusual, as the probe uses headspace air intake and does not come into contact with the liquid. Additionally, opening the bottle produced a pungent odor, which was absent in other water samples. The most significant difference between Qinghai-Tibet Plateau lake water and other water bodies is its extremely high salinity, which we suspect might be the cause affecting the measurements. We collected small green water droplets from the sample bottle pads and used inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine that the main elements in these droplets were iron and chromium, the main components of stainless steel. Analysis determined that the high chloride ion content in the saline lake water was the contributing factor. During pretreatment, a strong oxidant was added to oxidize DOC into carbon dioxide before mass spectrometry was used to measure isotopes. During oxidation, chloride ions were oxidized into chlorine gas. Chlorine gas has a strong, pungent odor and reacts with stainless steel. The injection needle, made of stainless steel, was corroded by chlorine gas, producing small green water droplets, which frequently caused clogging. Chlorine gas entering the mass spectrometer also caused signal instability, affecting the accuracy of δ¹³C measurements. Therefore, a suitable method needs to be found to reduce the chloride ion content in the water during pretreatment, and the generated chlorine gas needs to be removed before the gas enters the mass spectrometer.

[0003] The main methods for removing chloride ions from water are: 1. Adsorption: This method involves using an ion exchanger to exchange chloride ions with the water, thus fixing the chloride ions through adsorption. However, when lake water samples are passed through an adsorption column filled with an ion exchanger, the ion exchange capacity is limited, and saturation is easily reached. Using a larger column or connecting multiple columns can affect the soluble organic carbon in the brine, and this method is labor-intensive and costly, making it unsuitable for sample processing. 2. Evaporation: This method involves boiling and vaporizing water molecules at high temperatures, followed by condensation, separating the water molecules from the salt to remove chloride ions. Experiments have shown that this method is effective in removing chloride ions, but it also removes soluble organic carbon, making it unsuitable for this purpose as well. Therefore, there is a practical need for a simple, reliable, and easy-to-implement sample introduction technique for chloride removal using a mass spectrometry method for soluble organic carbon isotope determination. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a simple, reliable and easy-to-use sample dechlorination device for the mass spectrometry of soluble organic carbon isotopes.

[0005] To achieve the above objectives, the present invention provides a sample dechlorination device for the determination of soluble organic carbon isotopes. Its unique feature lies in the fact that the upstream and downstream ends of the centrally disconnected sample needle capillary are respectively sealed and connected to upstream and downstream thickened reducing pipe fittings. The thickened ends of these fittings are then jointly sealed and connected to a filter tube containing multiple axially parallel silver wire bundles. Thus, during headspace intake, the sample gas introduced from the upstream section of the centrally disconnected sample needle capillary flows through the filter tube. The silver wire bundles react with the chlorine in the sample gas to form silver chloride, which is then fixed. When the sample gas further flows into the downstream section of the centrally disconnected sample needle capillary, it will be chlorine-free, achieving a simple, reliable, and easy-to-use sample dechlorination. The filter tube is initially used in a forward connection with the head upstream and the tail downstream. After a certain number of filtration cycles, it is then used in a reverse connection with the tail upstream and the head downstream. Using the filter tubes in both forward and reverse directions allows for full utilization of the entire silver wire bundle filter element's chlorine removal function. However, after multiple forward uses, the chlorine removal intensity decreases from upstream to downstream, resulting in progressively increasing porosity within the filter tube, thus affecting upstream chlorine removal efficiency. Conversely, using the filter tubes in reverse order after multiple forward uses leverages the advantage of still having large porosity downstream and avoids the disadvantage of small porosity upstream. This reverse method maintains the high porosity upstream and low porosity downstream, maximizing the chlorine removal efficiency of the silver wire bundle. It offers the advantage of a simple, reliable, and easy-to-implement method for removing chlorine from gas-phase samples during soluble organic carbon isotope mass spectrometry.

[0006] As an optimization, the upstream and downstream thickened reducing pipe fittings consist of an internally threaded pipe head seat that is sealed to the upstream and downstream ends of the capillary tube, an internally threaded pipe base that is sealed to the end of the filter tube, and a reducing externally threaded pipe section whose two ends are respectively sealed and screwed to the internally threaded pipe holes of the internally threaded pipe head seat and the internally threaded pipe base by corrosion-resistant elastic sealing rings. This facilitates thickening and reducing the diameter and makes it convenient to disassemble and replace the filter element and filter tube. The filter tube is a metal tube or a transparent glass tube. Metal tubes have good durability, while transparent glass tubes allow for easy observation of the filling and filtration status. The outer narrow cavity of the downstream reducing externally threaded pipe section, which is screwed into the internally threaded pipe head seat, is equipped with a downstream silver wire bundle filter element that does not reverse synchronously with the filter tube. This allows the downstream silver wire bundle filter element to filter out chlorine residue in the downstream end of the reverse filter tube and its auxiliary pipe fittings when the filter tube is used in reverse, ensuring the chlorine removal efficiency when the filter tube is used in reverse.

[0007] As an optimization, the upstream and downstream ends of the metal capillary tube are respectively riveted, welded, or otherwise fixed to the outer opening of the upstream and downstream internally threaded tube head seats. This helps to ensure the strength of the sealing connection and provides good durability.

[0008] As an optimization, the inner openings of the upstream and downstream internally threaded pipe heads are respectively provided with internally threaded blind holes that extend into their inner cavities. The outer end of the upstream and downstream reducing externally threaded pipe sections has an outer-end externally threaded protrusion that mates with the internally threaded blind holes. The end face of the outer-end externally threaded protrusion is sealed to the end face of the internally threaded blind hole through the corrosion-resistant elastic sealing ring. This flexible connection facilitates disassembly, cleaning, and maintenance.

[0009] As an optimization, the upstream and downstream internally threaded pipe base is provided with a variable diameter cavity that is thinner inside and thicker outside. The thinner inner section of the upstream and downstream internally threaded pipe base is fitted with both ends of the filter pipe, and the thicker outer section of the internal thread is threaded with the outer threaded protrusion at the inner end of the upstream and downstream externally threaded pipe section.

[0010] A corrosion-resistant elastic sealing ring is provided between the inner end face of the externally threaded convex tube, the inner end face of the reducing cavity, and the outer periphery of the filter tube, allowing for independent disassembly, maintenance, and replacement of the filter tube; alternatively, both ends of the filter tube are provided with externally protruding baffles that abut against the inner end faces of the reducing cavities, with a corrosion-resistant elastic sealing ring provided between the inner end face of the externally threaded convex tube and the externally protruding baffles, providing high sealing strength and durability; or, in any of the upstream and downstream reducing externally threaded pipe sections, a corrosion-resistant elastic sealing ring is provided between the inner end face of the externally threaded convex tube, the inner end face of one of the reducing cavities in the upstream and downstream internally threaded pipe bases, and the outer periphery of one end of the filter tube, while the other end of the filter tube is provided with an externally protruding baffle that abuts against the inner end face of the reducing cavity in another internally threaded pipe base, with a corrosion-resistant elastic sealing ring provided between the inner end face of the externally threaded convex tube and the externally protruding baffle. One end allows for independent disassembly, maintenance, and replacement of the filter tube, while the other end provides high sealing strength and durability.

[0011] As an optimization, the upstream and downstream sections of the injection needle capillary and the upstream thickened reducer connector are made of copper for ease of use, disassembly, and maintenance, while the downstream thickened reducer connector is made of stainless steel for better durability and strength. The filter tube is either stainless steel or transparent glass. Stainless steel offers better durability, while transparent glass allows for easy observation of the filling and filtration status.

[0012] As an optimization, the upstream and downstream sections of the injection needle capillary are made of red copper for ease of use; the upstream thickened reducer fitting is made of brass for easy disassembly and maintenance. The upstream copper and downstream stainless steel materials are used to distinguish the upstream and downstream fittings and prevent them from being used interchangeably.

[0013] As an optimization, the filter tube contains multiple axially aligned, parallel silver wire bundles. The straight silver wires help ensure unobstructed filtration.

[0014] As an optimization, the straight silver wire is a variable diameter silver wire with successively thick and thin sections densely distributed along the axial direction. This significantly improves the scale-holding capacity and chlorine removal efficiency.

[0015] As an optimization, the filter tube contains multiple axially intertwined, parallel silver wire bundles, which significantly improve chlorine removal efficiency.

[0016] In other words, this new type of instrument modification involves adding a sealed, transparent glass or metal filter tube filled with silver wire to the middle of the sample needle capillary by thickening and reducing its diameter. This filter removes residual chlorine from the sample gas. Since silver and chlorine react rapidly to form silver chloride, the silver wire must be tightly packed to ensure efficient removal of chlorine from the gas, maximizing contact between the chlorine and the silver wire. Furthermore, silicone gaskets are used to seal the connections between the filter tube and the sample needle and mass spectrometer peripherals to ensure no leakage.

[0017] After adopting the above technical solution, the sample dechlorinator for the soluble organic carbon isotope mass spectrometry of this utility model has the advantage of being able to remove chlorine from the gas phase sample during the soluble organic carbon isotope mass spectrometry in a simple, reliable and easy manner. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the first embodiment of the sample dechlorination device for the soluble organic carbon isotope mass spectrometry of this invention. Figure 2 is a schematic diagram of the second embodiment of the sample dechlorination device for the soluble organic carbon isotope mass spectrometry of this invention. Detailed Implementation

[0019] Example 1, as shown in Figure 1, describes the sample dechlorination device for the soluble organic carbon isotope mass spectrometry of this invention. The upstream and downstream sections 11 and 12 of the intermediately disconnected sample needle capillary are respectively sealed and connected to upstream and downstream thickened reducing pipe fittings. The thickened ends of these fittings are then jointly sealed and connected to a filter tube 2 containing multiple axially parallel silver wire bundles. Thus, during headspace intake, the sample gas introduced from the upstream section of the intermediately disconnected sample needle capillary flows through the filter tube. The silver wire bundles react with the chlorine in the sample gas to form silver chloride, which is then fixed. When the sample gas further flows into the downstream section of the intermediately disconnected sample needle capillary, it will be free of chlorine, achieving a simple, reliable, and easy-to-use sample dechlorination. The filter tube is initially used in a forward connection with the head upstream and the tail downstream. After a certain number of filtration cycles, it is then used in a reverse connection with the tail upstream and the head downstream. Using the filter tubes in both forward and reverse directions allows for full utilization of the entire silver wire bundle filter element's chlorine removal function. However, after multiple forward uses, the chlorine removal intensity decreases from upstream to downstream, resulting in progressively increasing porosity within the filter tube, thus affecting upstream chlorine removal efficiency. Conversely, using the filter tubes in reverse order after multiple forward uses leverages the advantage of still having large porosity downstream and avoids the disadvantage of small porosity upstream. This reverse method maintains the high porosity upstream and low porosity downstream, maximizing the chlorine removal efficiency of the silver wire bundle. It offers the advantage of a simple, reliable, and easy-to-implement method for removing chlorine from gas-phase samples during soluble organic carbon isotope mass spectrometry.

[0020] Specifically, the upstream and downstream thickened reducing pipe fitting consists of an internally threaded pipe head seat that is sealed to the upstream and downstream sections 11 and 12 of the capillary tube, an internally threaded pipe base that is sealed to the filter tube 2, and a reducing externally threaded pipe section whose two ends are respectively sealed and screwed to the internally threaded pipe holes of the internally threaded pipe head seat and the internally threaded pipe base by corrosion-resistant elastic sealing rings.

[0021] More specifically, the upstream and downstream sections 11 and 12 of the metal capillary tube are riveted or welded to the outer openings of the upstream and downstream internally threaded pipe head seats 31 and 32, respectively. The inner openings of the upstream and downstream internally threaded pipe head seats 31 and 32 are respectively provided with internally threaded blind holes that extend into their inner cavities. The outer ends of the upstream and downstream reducing externally threaded pipe sections 51 and 52 have externally threaded protrusions that are threaded into the internally threaded blind holes. The end face of the externally threaded protrusions is sealed to the end face of the internally threaded blind holes through the corrosion-resistant elastic sealing ring.

[0022] More specifically, the upstream and downstream internally threaded pipe bases 41 and 42 are provided with a variable diameter cavity with a narrow inner side and a wide outer side. The narrow inner section cavity of the upstream and downstream internally threaded pipe bases 41 and 42 is fitted with both ends of the filter pipe 2, and the wide outer section cavity is threaded with the outer threaded convex pipe at the inner end of the upstream and downstream externally threaded pipe sections 51 and 52. A corrosion-resistant elastic sealing ring is provided between the inner end face of the externally threaded convex tube, the inner end face of the reducing cavity, and the outer periphery of the filter tube 2; alternatively, both ends of the filter tube may have externally protruding baffles that abut against the inner end faces of the reducing cavity, and a corrosion-resistant elastic sealing ring is provided between the inner end face of the externally threaded convex tube and the externally protruding baffles; alternatively, any one of the upstream and downstream reducing externally threaded pipe sections may have a corrosion-resistant elastic sealing ring provided between the inner end face of the externally threaded convex tube, the inner end face of one of the reducing cavities in the upstream and downstream internally threaded pipe bases, and the outer periphery of one end of the filter tube, and the other end of the filter tube may have an externally protruding baffle that abuts against the inner end face of the reducing cavity of another internally threaded pipe base, and a corrosion-resistant elastic sealing ring is provided between the inner end face of the externally threaded convex tube and the externally protruding baffles.

[0023] Specifically, the upstream and downstream sections 11 and 12 of the injection needle capillary and the upstream thickened reducer connector are made of copper, while the downstream thickened reducer connector and filter tube 2 are made of stainless steel. More specifically, the upstream and downstream sections of the injection needle capillary are made of red copper, and the upstream thickened reducer connector is made of brass.

[0024] Specifically, the filter tube 2 contains multiple axially aligned, parallel silver wire bundles 61. More preferably, the straight silver wires are variable-diameter wires with progressively thinner sections densely distributed axially. Preferably, the downstream variable-diameter external threaded pipe section, which is screwed into the internal threaded pipe head seat, has a downstream silver wire bundle filter element that does not reverse direction synchronously with the filter tube. This ensures that when the filter tube is used in reverse, the downstream silver wire bundle filter element removes residual chlorine from the downstream end of the reverse filter tube and its associated fittings, guaranteeing the chlorine removal efficiency when the filter tube is used in reverse. The upstream copper material and the downstream stainless steel material are used to distinguish between upstream and downstream fittings and prevent mixing.

[0025] Example 2, as shown in Figure 2, differs from Example 1 in that the sample dechlorination device for the soluble organic carbon isotope mass spectrometry of this invention has multiple axially intertwined silver wire bundles 69 inside the filter tube 2.

[0026] In other words, this new type of instrument modification involves adding a sealed, transparent glass or metal filter tube filled with silver wire to the middle of the sample needle capillary by thickening and reducing its diameter. This filter removes residual chlorine from the sample gas. Since silver and chlorine react rapidly to form silver chloride, the silver wire must be tightly packed to ensure efficient removal of chlorine from the gas, maximizing contact between the chlorine and the silver wire. Furthermore, silicone gaskets are used to seal the connections between the filter tube and the sample needle and mass spectrometer peripherals to ensure no leakage.

[0027] In summary, the sample dechlorinator for the soluble organic carbon isotope mass spectrometry of this invention has the advantage of being able to remove chlorine from the gas phase sample during the soluble organic carbon isotope mass spectrometry in a simple, reliable and easy manner.

Claims

1. A sample dechlorination device for the mass spectrometry determination of soluble organic carbon isotopes, characterized in that... The upstream and downstream ends of the discontinuous injection needle capillary are sealed and connected to the upstream and downstream thickened reducing pipe fittings, respectively. The thickened ends of the upstream and downstream thickened reducing pipe fittings are then jointly sealed and connected to the filter tube containing multiple axially parallel silver wire bundle filter elements.

2. The sample dechlorination device for the soluble organic carbon isotope mass spectrometry determination according to claim 1, characterized in that... The upstream and downstream thickened reducing pipe fitting consists of an internally threaded pipe head seat that is sealed to the upstream and downstream ends of the capillary tube, an internally threaded pipe base that is sealed to the end of the filter pipe, and a reducing externally threaded pipe section whose two ends are respectively sealed and screwed to the internally threaded pipe holes of the internally threaded pipe head seat and the internally threaded pipe base by corrosion-resistant elastic sealing rings; the filter pipe is a metal pipe or a transparent glass pipe.

3. The sample dechlorination device for the mass spectrometry determination of soluble organic carbon isotopes according to claim 2, characterized in that... The upstream and downstream ends of the metal capillary are respectively riveted or welded to the outer pipe openings of the upstream and downstream internally threaded metal pipe head seats.

4. The sample dechlorination device for the soluble organic carbon isotope mass spectrometry determination according to claim 2, characterized in that... The inner opening of the metal upstream and downstream internally threaded pipe head seat is provided with an internally threaded blind hole that extends into its inner cavity. The outer end of the metal upstream and downstream reducing externally threaded pipe section has an outer end externally threaded protrusion that is screwed into the internally threaded blind hole. The end face of the outer end externally threaded protrusion is sealed to the end face of the internally threaded blind hole through the corrosion-resistant elastic sealing ring.

5. The sample dechlorination device for the mass spectrometry determination of soluble organic carbon isotopes according to claim 2, characterized in that... The metal upstream and downstream internally threaded pipe base has a reducing cavity with a narrower inner diameter and a wider outer diameter. The metal upstream and downstream internally threaded pipe base also has a narrower inner section cavity that fits into both ends of the filter pipe and a wider inner thread section cavity that fits into the inner end of the externally threaded protrusion of the metal upstream and downstream externally threaded pipe section. A corrosion-resistant elastic sealing ring is provided between the end face of the externally threaded protrusion of the inner end of the reducing cavity and the outer circumference of the filter pipe; alternatively, both ends of the filter pipe have externally convex baffles that abut against the inner end faces of the reducing cavity, and the internally convex externally threaded protrusion... A corrosion-resistant elastic sealing ring is provided between the pipe end face and the externally protruding baffle; or a corrosion-resistant elastic sealing ring is provided between the end face of the externally threaded convex pipe on the inner side of any of the upstream and downstream reducing externally threaded pipe sections, the inner end face of a reducing cavity in the upstream and downstream internally threaded pipe base, and the outer periphery of one end of the filter pipe, and an externally protruding baffle is provided at the other end of the filter pipe to abut against the inner end face of the reducing cavity of another internally threaded pipe base, and a corrosion-resistant elastic sealing ring is provided between the end face of the externally threaded convex pipe on the inner side and the externally protruding baffle.

6. The sample dechlorination device for the soluble organic carbon isotope mass spectrometry determination according to claim 1, characterized in that... The upstream and downstream sections of the injection needle capillary and the upstream thickened reducer connector are made of copper, while the downstream thickened reducer connector is made of stainless steel; the filter tube is made of stainless steel or transparent glass.

7. The sample dechlorination device for the determination of soluble organic carbon isotopes according to claim 6, characterized in that... The upstream and downstream sections of the injection needle capillary are made of red copper, while the upstream thickened reducing tube fitting is made of brass.

8. The sample dechlorination device for the determination of soluble organic carbon isotopes according to claim 1, characterized in that... The filter tube contains multiple axially aligned, parallel silver wire bundles.

9. The sample dechlorination device for the mass spectrometry determination of soluble organic carbon isotopes according to claim 8, characterized in that... The straight silver wires arranged in parallel along the axial direction are silver wires of varying diameters that are densely distributed along the axial direction in sections of varying thickness.

10. The sample dechlorination device for the mass spectrometry of soluble organic carbon isotopes according to claim 1, characterized in that... The filter tube contains multiple axially intertwined, parallel silver wire bundles.

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