Analysis device and analysis method

Abstract

To provide an analysis device and analysis method for the continuous analysis of total nitrogen in a sample without using cadmium which is a cause of environmental pollution.SOLUTION: An analysis method includes: a sample introduction step of introducing a sample into a conduit; a pre-treatment step of converting total nitrogen in the sample into nitrate ions; a reduction step of reducing the nitrate ions in the sample pre-treated in the pre-treatment step transferred in the conduit to ammonium ions by transferring the sample through a hollow tube whose inner wall surface is made of zinc; a gas permeation step of gasifying the ammonium ions generated in the reduction step to perform separation; an ammonia gas absorption step of absorbing the gaseous ammonia obtained in the gas permeation step by a flow receiving reagent and converting it into ammonium ions; and an analysis step of analyzing the ammonium ions in the flow receiving reagent containing the ammonium ions transferred in the conduit. There is also provided an analysis device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an analysis device and an analysis method. [Background technology]

[0002] As methods for measuring total nitrogen in wastewater and environmental water, the summation method in JIS K 0102 45.1, the ultraviolet absorptiometry method in JIS K 0102 45.2, the copper-cadmium column reduction method in JIS K 0102 45.4, and the flow analysis method (ultraviolet absorptiometry and copper-cadmium column reduction method) in JIS K 0102 45.6 are prescribed (Non-Patent Document 1). However, the summation method requires Kjeldahl decomposition and distillation, and is a very complicated and time-consuming method. The ultraviolet absorptiometry method cannot accurately measure samples that contain a large amount of impurities that hinder analysis, such as seawater, brackish water, and wastewater. Therefore, in many cases where total nitrogen is measured, the copper-cadmium column reduction method is used.

[0003] In addition, for marine measurements, the Guidelines for Ocean Observation and GO-SHIP describe the use of flow analysis (copper-cadmium column reduction method) for nitric acid analysis, and the bubble segmented flow analysis method (copper-cadmium column reduction method) is used in most analyses (e.g., Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] JIS K 0102 [Non-Patent Document 2] GO-SHIP Repeat Hydrography Nutrient Manual, The precise and accurate determination of dissolved inorganic nutrients in seawater, using Continuous Flow Analysis methods, August 2019 Summary of the Invention [Problem to be solved by the invention]

[0005] The copper-cadmium column reduction method for measuring seawater, brackish water, etc., is capable of measuring with little influence of impurities, but has problems from the perspective of global environmental pollution, such as the problem that cadmium is contained in the wastewater after analysis and the problem that the copper-cadmium reduction column must be disposed of as specially controlled waste.

[0006] An object of the present invention is to provide an apparatus and method for continuously analyzing total nitrogen in a sample, which does not use cadmium, which causes environmental pollution, and has high measurement accuracy. [Means for solving the problem]

[0007] As a result of intensive research into solving the above problems, the inventors discovered that the above problems could be achieved by using a novel analytical device and analytical method that had never been used before, and thus completed the present invention.

[0008] That is, one embodiment of the present invention includes the following configuration.

[0009] [1] a sample introduction section for introducing a sample into a pipeline; a pretreatment section for converting all nitrogen in the sample into nitrate ions; a reduction section for reducing nitrate ions in the sample pretreated in the pretreatment section and transported through the pipeline to ammonium ions; a gas permeation section for gasifying and separating the ammonium ions generated in the reduction section; an ammonia gas absorption section that absorbs the gaseous ammonia that has permeated the gas permeation section by a receiving reagent to convert it into ammonium ions; An analysis unit that analyzes ammonium ions in a receiving reagent containing ammonium ions transported through a pipeline, The reduction section is a hollow tube having at least an inner wall surface made of zinc, and includes a reduction member through which a sample is transported.

[0010] [2] a sample introduction step of introducing a sample into a pipeline; A pretreatment step of converting all nitrogen in the sample into nitrate ions; a reduction step of reducing nitrate ions in the sample pretreated in the pretreatment step and transported through the pipeline to ammonium ions; a gas permeation step for gasifying and separating the ammonium ions produced in the reduction step; an ammonia gas absorption step in which the gaseous ammonia separated in the gas permeation step is absorbed by a receiving reagent to convert it into ammonium ions; and an analysis step of analyzing ammonium ions in a receiving reagent containing ammonium ions transported through the pipeline, The reduction step of this analytical method comprises reducing nitrate ions in the sample by transporting the sample through a hollow tube having at least an inner wall surface made of zinc. Effect of the Invention

[0011] According to one embodiment of the present invention, it is possible to provide an apparatus and method for continuously analyzing total nitrogen in a sample, which does not use cadmium, which causes environmental pollution, and has high measurement accuracy. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram showing a schematic configuration of an analysis device according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing a schematic configuration of an analysis device according to an embodiment of the present invention. [Diagram 3] 1 is a diagram showing a schematic configuration of an analysis device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing a schematic diagram of a gas permeable portion and an ammonia gas absorbing portion of the analyzer according to one embodiment of the present invention. [Diagram 5]FIG. 2 is a diagram showing the results of measurements of nitrate nitrogen at 1.00 mg / L, 0.50 mg / L, 0.25 mg / L, 0.10 mg / L, and 0.01 mg / L in an example. [Figure 6] FIG. 2 shows calibration curves for measurements of nitrate nitrogen at 1.00 mg / L, 0.50 mg / L, 0.25 mg / L, 0.10 mg / L, and 0.01 mg / L in an example. [Figure 7] FIG. 2 is a diagram showing the results of measurements of 1 mg / L of ammonium nitrogen and 1 mg / L of nitrate nitrogen in an example. [Figure 8] FIG. 2 is a diagram illustrating an example of a reducing member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The following describes in detail the embodiments of the present invention. However, the present invention is not limited to this, and various modifications are possible within the scope described, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. All academic documents and patent documents described in this specification are incorporated herein by reference. Furthermore, unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more (including A and greater than A) and B or less (including B and smaller than B)."

[0014] [1] Analyzer

[0015] An analytical device according to one embodiment of the present invention includes a sample introduction section that introduces a sample into a pipeline, a pretreatment section that converts all nitrogen in the sample into nitrate ions, a reduction section that reduces nitrate ions in the sample pretreated in the pretreatment section and transported through the pipeline to ammonium ions, a gas permeation section that gasifies and separates the ammonium ions produced in the reduction section, an ammonia gas absorption section that absorbs gaseous ammonia that has permeated through the gas permeation section with a receiving reagent to convert it into ammonium ions, and an analytical section that analyzes ammonium ions in the receiving reagent containing ammonium ions and transported through the pipeline, wherein the reduction section is located inside a hollow tube with at least an inner wall surface made of zinc, and includes a reduction member that allows the sample to be transported through the tube.

[0016] The above-mentioned analytical device enables continuous analysis of total nitrogen in a sample with high measurement accuracy without using cadmium, which causes environmental pollution. The total nitrogen in a sample refers to the total amount of inorganic nitrogen and organic nitrogen corresponding to ammonium ions, nitrite ions, and nitrate ions in the sample.

[0017] In one embodiment of the present invention, the analytical device may be a flow analytical device, which is capable of continuously introducing a sample into a pipeline, performing reduction in the pipeline, introducing a reagent into the pipeline to cause a reaction, and continuously measuring analytical data in an analytical section.

[0018] [1.1] Embodiment 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the drawings, in which: Fig. 1 shows a schematic configuration of a flow analyzer according to a first embodiment of the present invention.

[0019] The flow analyzer according to the first embodiment of the present invention comprises a sample introduction section 1 for introducing a sample into a pipeline 7, a pretreatment section 13 for pretreatment of the sample to convert all nitrogen in the sample into nitrate ions, a bubble segmentation section 4 for performing bubble segmentation on the sample transferred through the pipeline 7 after the pretreatment to create a plurality of segments in the pipeline 7 that are partitioned by bubbles, a reagent introduction section 5 for adding a reagent into the flow of the sample transferred through the pipeline 7, a reduction section 2 for reducing nitrate ions in the sample transferred through the pipeline 7 to convert them into ammonium ions, and a flow analyzer for reducing the nitrate ions in the sample transferred through the reduction section 2 to ammonium ions. The apparatus includes a reagent introducing section 5 which adds a reagent into the flow of the sample containing ammonium ions transported through the pipeline 7, a gas permeation section 6 which gasifies and separates the ammonium ions in the sample transported through the pipeline 7, an ammonia gas absorbing section 14 which absorbs ammonia gas in the sample with a receiving reagent to convert it into ammonium ions, the reagent introducing section 5 which adds a reagent into the flow of the sample containing ammonium ions transported through the pipeline 7 via the ammonia gas absorbing section 14, and an analysis section 3 which analyzes the ammonium ions in the sample.

[0020] The sample introduction unit 1 is a device for sampling a sample and introducing it into the pipeline 7. In one embodiment of the present invention, the sample introduction unit 1 includes a collection tube that introduces the sample into the pipeline 7, and a sampling pump that applies suction force to the collection tube. The sampling pump introduces the sample into the pipeline 7 at a predetermined flow rate. The sample is a liquid containing a substance or element to be analyzed.

[0021] The pretreatment unit 13 is a device for performing a pretreatment to convert all nitrogen in a sample into nitrate ions. In one embodiment of the present invention, the pretreatment unit 13 includes a reagent introduction unit for introducing a pretreatment reagent and a decomposition heating tank. The pretreatment reagent is a reagent that oxidizes nitrogen compounds in a sample into nitrate ions, and examples of such reagents include alkaline potassium peroxodisulfate. The reagent introduction unit for introducing the pretreatment reagent includes a collection tube that introduces the reagent into the pipe 7 and a sampling pump that applies suction to the collection tube. The sampling pump introduces the reagent into the pipe 7 at a predetermined flow rate. The sample into which the pretreatment reagent has been introduced is thermally decomposed in the decomposition heating tank, and all nitrogen in the sample becomes nitrate ions. The thermal decomposition tank may be configured, for example, such that the pipe 7 forming a coil or spiral is disposed in a thermostatic tank equipped with a heater. The thermal decomposition tank is also equipped with a pressurizing device that applies pressure against the flow of the sample from the downstream side of the thermal decomposition tank. The pressurizing device includes, for example, a compressor and a valve. By providing such a pressurizing device, the thermal decomposition in the thermal decomposition tank can be performed under high temperature and pressure. The pressure applied by the pressurizing device is not particularly limited, but is, for example, 0.12 MPa to 0.16 MPa. The temperature of the thermal decomposition is, for example, 100°C to 140°C, and the thermal decomposition time is, for example, 10 minutes to 60 minutes. In order to set the thermal decomposition time within the above range, for example, the length of the coiled pipe 7 in the thermal decomposition tank, the speed and flow rate of the sample flowing through the coiled pipe 7 in the thermal decomposition tank, etc. are adjusted. The configuration of the thermal decomposition tank is not limited to the above example, and instead of the thermostatic bath equipped with the heater, an ultrasonic decomposition device, a microwave, an autoclave decomposition device, etc. may be used. In the example of FIG. 1, a pretreatment device 13 is provided downstream of the sample introduction part 1 and upstream of the bubble segmentation part 4, but the pretreatment device 13 may be provided upstream of the sample introduction part 1, downstream of the sample introduction part 1, or may be incorporated into the sample introduction part 1.

[0022] The bubble segmentation unit 4 is a device for performing bubble segmentation on the sample introduced into the pipeline 7, and creating a plurality of segments in the pipeline 7, partitioned by bubbles. In one embodiment of the present invention, the bubble segmentation unit 4 includes a gas introduction tube for introducing gas into the pipeline 7, and a gas introduction pump for applying suction force to the gas introduction tube. By performing bubble segmentation, it is possible to suitably mix reagents and the like by vortexes in the segmented liquid divided by bubbles, and in the reduction unit 2, the frequency with which the sample transported through the tube comes into contact with the tube wall of the reduction unit 2 increases, so that nitrate ions in the sample can be sufficiently reduced to ammonium ions. In addition, the segmented liquid is divided by bubbles and flows independently through the pipeline 7, so that mutual diffusion between samples can be prevented. A method in which a reagent is introduced into a continuous flow in a pipeline in which the sample is divided by bubbles, a reaction operation is performed, and then an analysis is performed with a detector provided downstream is called continuous flow analysis (CFA). As the gas for the bubble segmentation, various gases such as inert gases, such as argon and helium; nitrogen, etc. can be used. These gases may be used alone or in a mixture of two or more. Among them, the gas is more preferably an inert gas, such as nitrogen, and / or argon and helium. If the gas is an inert gas, such as nitrogen and / or argon and helium, the gas does not contain oxygen, so that oxidation of the tube wall of the reduction section 2 by oxygen can be prevented. Therefore, it is preferable because the reduction rate of nitrate ions to ammonium ions can be maintained high.

[0023] The reagent introduction section 5 is a device for adding a reagent to the flow of the sample transported through the pipe 7. The reagent introduction section 5 includes a reagent introduction tube that introduces the reagent to the pipe 7, and a reagent introduction pump that imparts suction to the reagent introduction tube. The reagent added at the reagent introduction section 5, which is provided downstream of the air bubble division section 4 and upstream of the reduction section 2, can be a chelating agent. In one embodiment of the present invention, the analysis device includes a chelating agent introduction section for adding a chelating agent to the sample to capture metal ions. The chelating agent introduction section includes a chelating agent introduction tube that introduces the chelating agent to the pipe 7, and a chelating agent introduction pump that imparts suction to the chelating agent introduction tube. Examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA), citric acid, trans-1,2-cyclohexanediaminetetraacetic acid-hydrate (CyDTA), etc., and EDTA is preferred from the viewpoints of sufficient chelating ability and cost. By adding the chelating agent upstream of the reduction section 2, when zinc ions or copper ions are eluted from the reduction member into the sample in the subsequent reduction section 2, the chelating agent forms a stable complex with the eluted ions, thereby reducing the concentration of free zinc ions or copper ions. Therefore, the potential between zinc ions and zinc or between copper ions and copper can be reduced, and the reduction of nitrate ions to ammonium ions can be efficiently performed. In the example of FIG. 1, the reagent introduction section 5 is provided downstream of the air bubble segmentation section 4 and upstream of the reduction section 2, but the reagent introduction section 5 may be provided downstream of the pretreatment section 13 and upstream of the air bubble segmentation section 4.

[0024] The reduction unit 2 is a device for reducing nitrate ions in the sample transported through the pipe 7 to ammonium ions. The reduction unit 2 includes a reduction member that is a hollow tube with at least the inner wall surface made of zinc, and the sample is transported through the tube.

[0025] The reducing member is a hollow tube with at least the inner wall surface made of zinc, and a sample is transported through the tube, so that while the sample is being transported within the tube, nitrate ions that may be contained in the transported sample can be reduced to ammonium ions.

[0026] In this specification, "reducing nitrate ions that may be contained in a sample to form ammonium ions" and "reducing nitrate ions in a sample to form ammonium ions" mean that, when nitrate ions are contained in a sample, the nitrate ions contained therein are reduced to form ammonium ions.

[0027] The inner diameter of the tube of the reduction member is not limited thereto, but is preferably 0.5 mm to 1.5 mm, more preferably 0.6 mm to 1.4 mm, even more preferably 0.7 mm to 1.3 mm, particularly preferably 0.8 mm to 1.2 mm, and most preferably 1.0 mm to 1.2 mm. If the inner diameter is 0.5 mm or more, the sample can be transferred into the tube at a moderate speed. If the inner diameter is 1.5 mm or less, the sample transferred through the tube comes into contact with the tube wall more frequently, and therefore the nitrate ions in the sample can be sufficiently reduced, which is preferable.

[0028] The thickness of the tube wall of the tube of the reducing member is not limited thereto, but is preferably 0.1 mm to 1.5 mm, more preferably 0.2 mm to 1.0 mm, even more preferably 0.3 mm to 0.7 mm, and most preferably 0.4 mm to 0.6 mm. If the thickness is 0.1 mm or more, the strength as a reducing member is sufficient, which is preferable. Also, if the thickness is 1.5 mm or less, it is preferable because it can be processed into a desired shape.

[0029] The length of the tube of the reduction member is not limited to this, but is preferably 100 mm to 1000 mm, more preferably 200 mm to 900 mm, even more preferably 300 mm to 800 mm, and most preferably 500 mm to 800 mm. If the length is 100 mm or more, the sample transported through the tube comes into contact with the tube wall more frequently, and therefore the nitrate ions in the sample can be sufficiently reduced, which is preferable. Also, if the length is 1000 mm or less, the transport of the sample does not take too much time, and the time required for analysis can be shortened.

[0030] The cross-sectional shape of the tube of the reduction member is usually circular, but may be elliptical or polygonal.

[0031] The shape of the tube of the reducing member is not particularly limited, and may be linear or curved. Among them, the shape is more preferably curved, and more preferably a shape that moves in a direction perpendicular to the surface of a figure such as a circle. The shape is not particularly limited, but may be, for example, a circle, an ellipse, a figure of eight, etc., and the shape of the tube may be, for example, a spiral shape, a figure of eight spiral shape, etc. FIG. 8 shows an example of a reducing member. FIG. 8 (a) shows a spiral reducing member, and FIG. 8 (b) shows a figure of eight spiral reducing member. According to the shape, the sample transported in the tube is transported while rotating in the tube, so that the sample is mixed uniformly and the frequency of contact with the tube wall of the tube increases. Therefore, it is preferable because the nitrate ions in the sample can be sufficiently reduced. The number of turns of the spiral such as the spiral shape and the figure of eight spiral shape is not particularly limited, but may be, for example, 1 turn to 20 turns, more preferably 2 turns to 10 turns, and even more preferably 4 turns to 7 turns. It is preferable that the number of turns is 1 or more, since the sample is mixed more uniformly and the frequency of contact with the wall of the tube is increased, and it is preferable that the number of turns is 20 or less, since the device can be made compact.

[0032] When the shape of the tube is, for example, a spiral, the outer diameter of the spiral (referred to as the "coil diameter") is not particularly limited, but is, for example, 10 mm to 70 mm, more preferably 15 mm to 60 mm, even more preferably 20 mm to 50 mm, and most preferably 25 mm to 40 mm. If the coil diameter is 10 mm or more, it is preferable because the liquid can be stably transported. Also, if the coil diameter is 70 mm or less, it is preferable because the liquid can be mixed more appropriately.

[0033] When the shape of the tube is, for example, a helical shape, the coil pitch is not particularly limited, but is, for example, 0.7 mm to 40 mm, more preferably 0.8 mm to 30 mm, and even more preferably 0.9 mm to 25 mm. If the coil pitch is 0.7 mm or more, it is preferable because a reducing member wound with a tube of a preferred diameter can be formed. Also, if the coil diameter is 40 mm or less, it is preferable because the size of the reducing member does not take up space. Also, when the shape of the tube is, for example, a helical shape, it is also preferable to wind the tube closely without leaving any gaps. In such a case, the coil pitch is also not particularly limited, but is, for example, 0.7 mm to 5.0 mm, more preferably 1.0 mm to 4.5 mm, and even more preferably 1.2 mm to 4.0 mm.

[0034] When the shape of the tube is, for example, a figure-of-eight spiral, the maximum length of the figure-of-eight is the same as the coil diameter in the case of the spiral, and the pitch is the same as the coil pitch in the case of the spiral.

[0035] The tube of the reducing member may be a tube with at least an inner wall surface made of zinc. According to this configuration, zinc functions as a reducing agent and can reduce nitrate ions to ammonium ions. Furthermore, by using zinc, it is possible to eliminate the use of cadmium, thereby solving the problem of environmental burden. It is more preferable that the entire tube of the reducing member is made of zinc, in terms of the safety of the metal used, ease of manufacture, and long-term use as a reducing agent.

[0036] It is more preferable that the zinc forming the tube or the inner wall surface of the tube of the reducing member is coated with copper at least on the inside of the tube. By coating the inside of the tube with copper, the reduction rate of nitrate ions to ammonium ions can be increased. The thickness of the copper coating is not particularly limited, but is, for example, 0.5 μm to 300 μm, more preferably 10 μm to 200 μm. If the thickness of the copper coating is 0.5 μm or more, it is preferable because the reduction rate of nitrate ions to ammonium ions can be increased for a long period of time. In addition, if the thickness of the copper coating is 300 μm or less, it is preferable because the inner diameter of the tube does not become too small. The method of coating the zinc forming the tube with copper is not particularly limited, but for example, a method of immersing the hollow tube, at least the inner wall surface of which is made of zinc, in a copper sulfate aqueous solution containing a chelating agent such as ethylenediaminetetraacetic acid (EDTA) can be mentioned. In this method, the content of the chelating agent relative to the total weight of the copper sulfate aqueous solution is preferably 1 wt % to 10 wt %. The content of copper sulfate relative to the total weight of the aqueous copper sulfate solution is preferably 0.5% by weight to 5% by weight. The pH of the aqueous copper sulfate solution in which the tube is immersed is preferably 6 to 8, and the immersion time is preferably 12 hours to 24 hours. Alternatively, the tube or zinc forming the inner wall surface of the tube may be coated with copper by a method of flowing the aqueous copper sulfate solution inside the hollow tube having at least the inner wall surface made of zinc or a method of retaining the aqueous copper sulfate solution inside the tube.

[0037] The conduit 7 is connected to both ends of the tube of the reducing member in the reduction section 2, and the sample transported through the conduit 7 is continuously transported through the tube of the reducing member, and the sample that has passed through the tube is continuously transported through the conduit 7. In other words, the tube of the reducing member in the reduction section 2 becomes the conduit 7. The connection parts between the conduit 7 and both ends of the tube of the reducing member in the reduction section 2 are connected so that the sample and gas transported through the tube are sealed within the conduit. The inner diameter of the conduit 7 and the inner diameter of the tube of the reducing member in the reduction section 2 may be the same or different, as long as the sample can be transported continuously.

[0038] The reagent introduction section 5, which adds a reagent to the flow of the sample containing ammonium ions transported through the pipe 7 via the reduction section 2, is provided downstream of the reduction section 2 and upstream of the gas permeation section 6. The reagent introduction section 5 includes a reagent introduction tube that introduces the reagent to the pipe 7, and a reagent introduction pump that applies suction force to the reagent introduction tube. An example of the reagent added at the reagent introduction section 5, which is provided downstream of the reduction section 2 and upstream of the gas permeation section 6, is an alkali such as sodium hydroxide, which is a reagent that makes the pH alkaline. By adding an alkali downstream of the reduction section 2 and upstream of the gas permeation section 6, the ammonium ions in the sample can be gasified to ammonia gas. In addition, a buffer solution in which boric acid or the like is added to the alkali such as sodium hydroxide may be added. In one embodiment of the present invention, the ammonium ions are gasified by adding sodium hydroxide and boric acid. However, the alkali is not limited to sodium hydroxide, and any reagent that makes the pH alkaline can be appropriately selected. The reagent for preparing the buffer solution is not limited to boric acid, and other buffer solutions may be appropriately selected and added.

[0039] The gas permeation section 6 is a device that separates gaseous ammonia by allowing it to permeate. FIG. 4 is a diagram that shows the gas permeation section 6 and the ammonia gas absorption section 14. As shown in FIG. 4, when a sample containing gaseous ammonia (indicated as "sample + reagent" in FIG. 4) is transferred to the gas permeation section 6, only ammonia gas in the sample permeates the polytetrafluoroethylene (PTFE) porous filter 12 of the gas permeation section 6, and the remaining part of the sample is discharged as waste liquid. The ammonia gas that permeates the PTFE porous filter 12 is absorbed by the receiving reagent in the ammonia gas absorption section 14 and becomes ammonium ions again. The receiving reagent that has absorbed the ammonium ions is transferred through the pipe 7 connected downstream of the ammonia gas absorption section 14 and is subjected to analysis. In FIG. 4, in order to show that the ammonia gas permeates the PTFE porous filter 12, NH3 is written even after permeating the PTFE porous filter 12, but it is not clear whether the ammonia gas is absorbed by the receiving reagent and becomes NH4. +The gas permeable membrane provided in the gas permeable portion is preferably a polytetrafluoroethylene (PTFE) porous filter, but is not limited thereto as long as it is a filter that selectively allows gaseous ammonia to pass therethrough.

[0040] The gaseous ammonia is selectively allowed to permeate and separated by the gas permeation section 6, whereby the amount of ammonium ions in the sample reduced by the reduction section 2, in other words, the amount of nitrogen in the nitrate ions reduced to ammonia ions, i.e., the total nitrogen in the sample to be analyzed, can be accurately analyzed.

[0041] In addition, by providing the gas permeable portion 6, the baseline of the measurement chart can be stabilized in the quantitative determination of ammonium ions by indophenol blue absorptiometry using salicylic acid. The indophenol blue absorptiometry using salicylic acid is preferable to the indophenol blue absorptiometry using phenol in that it does not use phenol, which is a chemical substance harmful to the human body, and that phenol is not discharged into the environment.

[0042] The ammonia gas absorption section 14 is a device that absorbs gaseous ammonia that has permeated the gas permeation section with a receiving reagent to convert it into ammonium ions. The receiving reagent is not particularly limited as long as it is a reagent that can absorb gaseous ammonia and convert it into ammonium ions, and for example, an acid such as sulfuric acid can be used. The acid is not limited to sulfuric acid, and a reagent that absorbs gaseous ammonia can be appropriately selected. In addition to the acid such as sulfuric acid, a reagent used for detecting ammonium ions may be included. Examples of such reagents include reagents such as nitroprusside Na used in indophenol blue absorptiometry. The receiving reagent may be supplied segmented with air bubbles. Examples of gases that can be used for the bubble segmentation include various gases such as inert gases such as argon and helium; nitrogen; oxygen; and air.

[0043] The reagent introduction section 5, which adds a reagent to the flow of the sample containing ammonium ions transported through the pipe 7 via the ammonia gas absorption section 14, is provided downstream of the ammonia gas absorption section 14 and upstream of the analysis section 3. The reagent introduction section 5 includes a reagent introduction tube that introduces the reagent to the pipe 7, and a reagent introduction pump that applies suction force to the reagent introduction tube. Examples of the reagent added by the reagent introduction section 5 provided downstream of the ammonia gas absorption section 14 and upstream of the analysis section 3 include reagents such as salicylic acid and phenol that are used to quantify ammonium ions generated by the reduction of nitrate ions by indophenol blue absorptiometry. Among these, the indophenol blue absorptiometry using salicylic acid is preferable compared to the indophenol blue absorptiometry using phenol in that it does not use phenol, which is a chemical substance harmful to the human body, and that phenol is not discharged into the environment. In the indophenol blue absorptiometry using salicylic acid, for example, salicylic acid and hypochlorous acid, such as sodium hypochlorite (NaClO), are added as reagents. In this case, it is preferable that salicylic acid and NaClO are added from two separate, different sample introduction parts. The order in which salicylic acid and NaClO, etc. are added may be either first, but it is more preferable to add salicylic acid and then NaClO. In the indophenol blue absorptiometry using phenol, the method is the same as the indophenol blue absorptiometry using salicylic acid, except that salicylic acid is replaced with phenol. For example, phenol and NaClO are added as reagents. In this case, it is preferable that phenol and NaClO are added from two separate, different sample introduction parts. The order in which phenol and NaClO are added may be either first, but it is more preferable to add NaClO after adding phenol.

[0044] The analysis unit 3 is a device that performs analysis of ammonium ions in a sample. In one embodiment of the present invention, when the indophenol blue absorptiometry is adopted as the analysis method, the analysis unit 3 is, for example, an absorptiometer. As the absorptiometer, a flow cell type absorptiometer is more preferable. However, the analysis unit 3 is not limited thereto and can be appropriately selected according to the analysis method to be used. For example, the distillate reduced in the reduction unit 2 can be fractionated, and the fractionated sample or the sample in the flow of the continuous flow analyzer can be measured by ion chromatography. Alternatively, the measurement can be performed by an ion electrode method, a titration method, a voltammetry method, and an ion chromatograph. The analysis is a quantitative analysis, but may also be a qualitative analysis.

[0045] In the example of FIG. 1, the flow analyzer is provided with three reagent introduction parts 5, but in addition to the above-mentioned reagent introduction parts 5, further reagent introduction parts 5 may be provided as necessary. Also, if the reagents can be mixed and introduced, the number of reagent introduction parts may be reduced. Examples of the reagent introduced at the reagent introduction part 5 include, but are not limited to, acids such as nitric acid, hydrochloric acid, sulfuric acid, perchloric acid, phosphoric acid, hydrogen peroxide, and hydrofluoric acid; and alkalis such as sodium peroxide, calcium carbonate, and sodium carbonate. The pH of the sample can be adjusted by adding these reagents. Also, the reagents used in the analysis are not limited to the above-mentioned reagents, and may be appropriately selected depending on the analysis method.

[0046] Although not provided in the example of FIG. 1, the flow analyzer according to one embodiment of the present invention may further include a mixing coil for mixing the reagent added at the reagent introduction unit 5 with the sample flowing in the pipeline 7. The mixing coil is the pipeline 7 formed in a coil shape, and when the sample passes through the mixing coil, the reagent and the sample flowing in the pipeline 7 are mixed. The shape of the mixing coil is not particularly limited, but may be the same as the shape of the reducing member shown in FIG. 8. The position where the mixing coil is provided may be after each reagent introduction unit 5 or after multiple reagent introduction units 5.

[0047] Although not provided in the example of FIG. 1, the flow analyzer according to one embodiment of the present invention may include a heating tank for performing a heat treatment on the sample transported through the pipe 7. The heating tank may be a thermostatic tank equipped with a heater. However, the configuration of the heating tank is not limited thereto, and may be an ultrasonic decomposition device, a microwave decomposition device, an autoclave decomposition device, or the like. In addition, the pipe 7 forms a coil or a spiral in the heating tank. In one embodiment of the present invention, the heating tank is provided downstream of the reagent introduction section 5 or downstream of the mixing coil. By heating a sample to which a reagent has been added or a sample mixed with a reagent, the reaction of the sample with the reagent can be promoted.

[0048] Although not provided in the example of FIG. 1, the flow analyzer according to one embodiment of the present invention may further include a pool tank (liquid reservoir) in the middle of the pipe 7. The flow analyzer is a method of flowing a sample in a closed space for analysis, so the pressure may become high. Even in such a case, by providing a pool tank, the pressure can be released and the volume required for each process can be suitably dispensed and collected. As a means for releasing the pressure in the flow analyzer, in addition to the pool tank, for example, a debubbler that discharges an appropriate amount of air (gas) and liquid, a pressure reducing valve, etc. may be provided. In addition, when the flow analyzer is provided with a pool tank, a debubbler, a pressure reducing valve, etc., a bubble segmentation unit 4 that newly introduces gas into the pipe 7 may be provided downstream of the pool tank. The flow analyzer may be provided with multiple pool tanks, debubblers, pressure reducing valves, etc. In addition, the flow analyzer may be provided with multiple bubble segmentation units 4.

[0049] Furthermore, the flow analyzer according to one embodiment of the present invention may include a pressure device that applies pressure against the flow of the sample from the downstream side of the heating tank. The pressure device includes, for example, a compressor and a valve. By including such a pressure device, it is possible to suppress the expansion of bubbles in the heating tank and promote the reaction in the heating tank by the synergistic effect of heating and pressurization. The pressure applied by the heating tank is not particularly limited, but is, for example, 0.14 MPa or less.

[0050] Moreover, in the flow analyzer according to one embodiment of the present invention, an autosampler can be used as the sample introduction section 1. Furthermore, an ultrasonic homogenizer or a stirrer may be provided to crush and / or stir the sample before sampling.

[0051] Alternatively, the flow analyzer according to one embodiment of the present invention may further include a dilution device in the pipeline 7. This allows the desired dilution to be automatically performed in the flow analyzer when dilution is required depending on the concentration of the sample. A commercially available automatic dilution device can be suitably used as such a dilution device.

[0052] According to the flow analyzer of one embodiment of the present invention, the total nitrogen contained in a sample can be quantified. The flow analyzer of one embodiment of the present invention is an apparatus in which a pretreatment section for pretreating a sample to convert the total nitrogen in the sample into nitrate ions is incorporated in the sample introduction section 1 or downstream of the sample introduction section 1. The total nitrogen in the sample can be converted into nitrate ions, for example, by oxidative decomposition using potassium peroxodisulfate. By providing such a pretreatment section, the total nitrogen in the sample can be decomposed into nitrate ions in the pretreatment section, and then the nitrate ions can be reduced to ammonium ions for quantitative determination, making it possible to continuously measure the total nitrogen in the sample. In particular, for samples such as seawater and brackish water, copper-cadmium reduction methods and the like have been used so far due to the influence of coexisting bromide ions and salts, but according to the flow analyzer of one embodiment of the present invention, the total nitrogen in a sample (for example, a sample from seawater or brackish water) can be continuously analyzed with good measurement accuracy without using cadmium, which causes environmental pollution. Furthermore, by incorporating such a pretreatment unit into the flow analyzer according to one embodiment of the present invention, the entire process from pretreatment to analysis can be carried out in one step.

[0053] Furthermore, the flow analyzer according to one embodiment of the present invention may be an apparatus in which a device for preparing a liquid sample by processing a sample other than a liquid, such as a solid, is incorporated into the sample introduction section 1, or an apparatus in which a device for preparing a liquid sample is incorporated upstream of the sample introduction section 1. A flow analyzer is an apparatus for analyzing a liquid sample using a flow analysis method, and cannot directly measure a sample other than a liquid, such as a solid. Therefore, by incorporating an apparatus for preparing a liquid sample by pretreating a sample other than a liquid, such as a solid, it is possible to consistently perform the process from pretreatment to analysis of a sample other than a liquid, such as a solid.

[0054] [1.2] Embodiment 2 2 shows a schematic configuration of a flow analyzer according to a second embodiment of the present invention. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the first embodiment, and the explanation thereof will not be repeated.

[0055] The flow analysis device according to the second embodiment of the present invention uses flow injection analysis (FIA), in which a reagent is introduced into a sample flow in a pipeline that is not segmented by bubbles, a reaction operation is performed, and then analysis is performed using a detector installed downstream.

[0056] The flow analyzer according to the second embodiment of the present invention includes a carrier introduction section 8 for introducing a carrier into a pipeline 7, a sample introduction section 1 for introducing a sample into the pipeline 7, a pretreatment section 13 for pretreatment of the sample to convert all nitrogen in the sample into nitrate ions, a reagent introduction section 5 for adding a reagent into the flow of the sample transferred through the pipeline 7 after the pretreatment, a reduction section 2 for reducing nitrate ions in the sample transferred through the pipeline 7 to ammonium ions, a reagent introduction section 5 for adding a reagent into the flow of the sample containing ammonium ions transferred through the pipeline 7 via the reduction section 2, a gas permeation section 6 for gasifying and separating ammonium ions in the sample transferred through the pipeline 7, an ammonia gas absorption section 14 for absorbing ammonia gas in the sample with a receiving reagent to convert it into ammonium ions, a reagent introduction section 5 for adding a reagent into the flow of the sample containing ammonium ions transferred through the pipeline 7 via the ammonia gas absorption section 14, and an analysis section 3 for analyzing ammonium ions in the sample.

[0057] The flow analysis device of embodiment 2 is provided with a carrier introduction section 8 upstream of a sample introduction section 1 for introducing a sample into a pipeline 7, and has the same configuration as the flow analysis device shown in Figure 1 except that no bubble segmentation section is provided.

[0058] The flow analysis device of embodiment 2 is an analysis device that uses flow injection analysis (FIA), in which a carrier is introduced into a pipeline 7 through a carrier introduction section 8, and a sample is introduced into the flow in pipeline 7 through which the carrier flows through a sample introduction section 1.

[0059] The carrier is not particularly limited as long as it is a liquid that does not adversely affect the pretreatment and analysis of the sample, and examples thereof include water, a surfactant, an acidic solution, and an alkaline solution.

[0060] The other configuration of the flow analyzer according to the second embodiment is the same as that described in the first embodiment, and therefore description thereof will be omitted.

[0061] [2] Analysis method An analysis method according to one embodiment of the present invention will be described below. For the sake of convenience, the description of the analysis apparatus described in [1] will not be repeated.

[0062] An analytical method according to one embodiment of the present invention includes a sample introduction step of introducing a sample into a pipeline; a pretreatment step of converting all nitrogen in the introduced sample into nitrate ions; a reduction step of reducing nitrate ions in the sample pretreated in the pretreatment step and transported through the pipeline to ammonium ions; a gas permeation step of gasifying and separating the ammonium ions generated in the reduction step; an ammonia gas absorption step of absorbing the gaseous ammonia separated in the gas permeation step with a receiving reagent to convert it into ammonium ions; and an analysis step of analyzing ammonium ions in the receiving reagent containing ammonium ions and transported through the pipeline, in which the reduction step reduces nitrate ions in the sample by transporting the sample through a hollow tube with at least an inner wall surface made of zinc.

[0063] The sample introduction step is a step of introducing samples into a pipeline, and involves, for example, sampling a plurality of samples using a sampling device and introducing them successively and continuously into pipeline 7 at a predetermined flow rate.

[0064] The pretreatment step is a step of converting all nitrogen in a sample into nitrate ions. For example, a sample to which a peroxo reagent has been added is passed through a tube in a thermal decomposition tank, and decomposition is carried out under high temperature and pressure, thereby converting all nitrogen in the sample into nitrate ions.

[0065] The reduction step is a step of reducing nitrate ions in the sample transported through the pipe to ammonium ions, and reduces nitrate ions in the sample by transporting the sample through a hollow pipe having at least an inner wall surface made of zinc, i.e., the reduction member described above.

[0066] The gas permeation step is a step of gasifying and separating the ammonium ions produced in the reduction step.

[0067] The ammonia gas absorption step is a step in which gaseous ammonia that has permeated the gas permeable portion is absorbed by a flow-receiving reagent to convert it into ammonium ions.

[0068] The analysis step is a step of analyzing the ammonium ions absorbed by the receiving reagent in the ammonia gas absorption step, i.e., the ammonium ions in the sample generated in the reduction step. Here, the analysis includes detection of the presence or absence of an analyte or measurement of its concentration. The analysis may be quantitative or qualitative. The analysis method is not particularly limited and may be any analysis, but examples thereof include indophenol blue absorptiometry using salicylic acid, indophenol blue absorptiometry using phenol, ion chromatography, ion electrode method, titration, voltammetry, and the like.

[0069] 〔summary〕 An embodiment of the present invention includes the following configuration.

[0070] [1] a sample introduction section for introducing a sample into a pipeline; a pretreatment section for converting all nitrogen in the sample into nitrate ions; a reduction section for reducing nitrate ions in the sample pretreated in the pretreatment section and transported through the pipeline to ammonium ions; a gas permeation section for gasifying and separating the ammonium ions generated in the reduction section; an ammonia gas absorption section in which the gaseous ammonia that has permeated the gas permeation section is absorbed by a receiving reagent to convert the gaseous ammonia into ammonium ions; An analysis unit that analyzes ammonium ions in a receiving reagent containing ammonium ions transported through a pipeline, The reduction section is a hollow tube having at least an inner wall surface made of zinc, and includes a reduction member through which a sample is transported.

[0071] [2] The analytical device described in [1], wherein the hollow tube is spiral or figure-eight spiral.

[0072] [3] The analytical device described in [1] or [2], wherein at least the inner wall surface of the hollow tube is coated with copper.

[0073] [4] The analytical device according to any one of [1] to [3], which is a flow analytical device.

[0074] [5] An analytical device described in any one of [1] to [4], which is provided with a bubble segmentation section that performs bubble segmentation on a sample introduced into the pipeline, thereby creating multiple segments within the pipeline that are partitioned by bubbles.

[0075] [6] The analytical device described in [5], wherein the gas bubbles are nitrogen, argon, or helium.

[0076] [7] The analytical device according to any one of [1] to [6], further comprising a reagent introduction section for introducing a reagent for quantifying ammonium ions generated in the ammonia gas absorption section by indophenol blue absorptiometry using salicylic acid.

[0077] [8] The analytical device according to any one of [1] to [7], further comprising a chelating agent introduction section for adding a chelating agent to a sample to capture metal ions.

[0078] [9] The analytical device described in [8], wherein the chelating agent is ethylenediaminetetraacetic acid (EDTA).

[0079]

[10] The analytical device according to any one of [1] to [9], wherein the gas permeable membrane provided in the gas permeable portion is a PTFE porous filter.

[0080]

[11] a sample introduction step of introducing a sample into a pipeline; A pretreatment step of converting all nitrogen in the sample into nitrate ions; a reduction step of reducing nitrate ions in the sample pretreated in the pretreatment step and transported through the pipeline to ammonium ions; a gas permeation step for gasifying and separating the ammonium ions produced in the reduction step; an ammonia gas absorption step in which the gaseous ammonia separated in the gas permeation step is absorbed by a receiving reagent to convert it into ammonium ions; and an analysis step of analyzing ammonium ions in a receiving reagent containing ammonium ions transported through the pipeline, The reduction step reduces nitrate ions in a sample by transporting the sample through a hollow tube having at least an inner wall surface made of zinc.

[12] The analytical method according to

[11] , wherein the gasification of the ammonium ions produced in the reduction step includes making the pH of the sample alkaline by adding sodium hydroxide and boric acid. EXAMPLES

[0081] The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Examples obtained by appropriately combining the technical means disclosed in each example are also included in the scope of the present invention.

[0082] [reagent] The reagents used in the examples are shown below.

[0083] (1) Peroxo Reagents 5.0 g of potassium peroxodisulfate, 4.0 g of boric acid, and 0.5 g of sodium chloride were added and dissolved in approximately 400 mL of pure water, after which 5.0 mL of 5N-NaOH was added, and the mixture was then made up to 500 mL with pure water.

[0084] (2) Chelating agent 7.5 g of disodium ethylenediaminetetraacetate was added and dissolved in approximately 600 mL of pure water, the solution was adjusted to pH 10 with 80 g / L sodium hydroxide, and the solution was made up to 1000 mL with pure water.

[0085] (3) Alkaline reagent 30 g of boric acid and 30 g of sodium hydroxide were dissolved in about 800 mL of pure water, and the solution was made up to 1000 mL with pure water. 2 mL of 20% Triton-100 was added to the resulting solution, and the solution was gently stirred.

[0086] (4) Sulfuric acid reagent 1 mL of concentrated sulfuric acid and 0.1 g of sodium pentacyanonitrosylferrate (III) were dissolved in approximately 800 mL of pure water, and the solution was made up to 1000 mL with pure water. 4 mL of 20% Triton-100 was added to the resulting solution, and the solution was gently stirred.

[0087] (5) Salicylic acid reagent 10 g of sodium tartrate, 30 g of sodium hydroxide, 30 g of boric acid, and 50 g of sodium salicylate were dissolved in approximately 400 mL of pure water, and the solution was made up to 500 mL with pure water.

[0088] (6) Hypochlorous Acid Reagent 25 mL of sodium hypochlorite (a commercially available product with approximately 10% available chlorine) and 5 g of sodium hydroxide were dissolved in approximately 400 mL of pure water, and the solution was made up to 500 mL with pure water.

[0089] [Device] A flow analyzer (CFA) shown in Figure 3 was used. The flow analyzer includes a sample introduction section for introducing a sample into a pipeline 7, a pretreatment section 13 for converting all nitrogen in the sample into nitrate ions by flowing the sample in a decomposition heating tank for 30 minutes, a bubble segmentation section for performing nitrogen bubble segmentation on the sample transferred through the pipeline 7 after the pretreatment, a chelating agent introduction section for adding a chelating agent reagent into the sample flow transferred through the pipeline 7, a mixing coil 11 for mixing the sample and the added chelating agent reagent in each segment segmented by nitrogen bubbles, a reduction section 2 for reducing nitrate ions in the sample transferred through the pipeline 7 to ammonium ions, a mixing coil 11 for mixing the sample transferred through the pipeline 7 via the reduction section, a reagent introduction section for adding an alkaline reagent into the sample flow containing ammonium ions transferred through the pipeline 7, a mixing coil 11 for mixing the sample and the alkaline reagent in each segment segmented by nitrogen bubbles, and a sample containing ammonia transferred through the pipeline 7 via the mixing coil 11. the mixing coil 11 mixes the sample in each segment segmented by air bubbles; a gas permeation section 6 allows gaseous ammonia generated by the addition of the alkaline reagent to permeate and separate it; an ammonia gas absorption section 14 allows the gaseous ammonia that has permeated through to be absorbed by the sulfuric acid reagent segmented by air; a reagent introduction section that adds salicylic acid reagent to the flow of the sulfuric acid reagent that has absorbed ammonia gas; the mixing coil 11 mixes the sample and salicylic acid reagent in each segment segmented by air; a reagent introduction section that adds hypochlorous acid reagent to the reagent transported in the pipeline 7; the mixing coil 11 mixes the sample and hypochlorous acid reagent in each segment segmented by air; a heating tank 9 reacts ammonium ions in the sample with salicylic acid and hypochlorous acid; and an analysis section (color reaction section and detection section) that analyzes ammonium ions in the sample. A flow cell type absorptiometer (BL Tech Co., Ltd., SCIC3000) was used for the analysis section. The cell length of the flow cell 10 was 50 mm, and measurements were performed at a wavelength of 660 nm.The flow analyzer automatically performed all steps from the sample introduction step of introducing a sample into a pipeline to the analysis step of analyzing ammonium ions in a receiving sample containing ammonium ions.

[0090] The temperature of the decomposition heating tank in the pretreatment section was 120° C., and the pressure was 0.14 MPa.

[0091] The heating tank 9 had a mixing coil disposed therein, and the temperature inside the heating tank 9 was set to 45°C.

[0092] A hollow zinc tube with copper coating on the inside was used as the reduction member of the reduction section 2. The hollow zinc tube was a coil made by winding a tube with a length of 380 mm, an inner diameter of 1.2 mm, and an outer diameter of 2.0 mm in a spiral shape. The thickness of the copper coating was 10 μm to 20 μm. The coil diameter (outer diameter) was 30 mm.

[0093] [Example 1: Measurement of standard solution] Standard solutions were prepared so that the concentrations of nitrate nitrogen (nitrate ion) were 1.00 mg / L, 0.50 mg / L, 0.25 mg / L, 0.10 mg / L, and 0.01 mg / L, respectively, and introduced into the flow analyzer to perform flow analysis. The measurement chart of nitrate nitrogen at each concentration is shown in Figure 5. The calibration curve as the measurement result is shown in Figure 6.

[0094] As shown in Figure 6, a calibration curve with a correlation coefficient of 0.9998 was obtained. This result shows that total nitrogen in nitrate nitrogen (nitrate ion) can be accurately measured at any concentration in the range of 0.01 to 1.00 mg / L.

[0095] [Example 2: Measurement of standard solution] A standard solution was prepared so that the ammonia nitrogen (ammonium ion) and nitrate nitrogen (nitrate ion) were each 1 mg / L, and introduced into the flow analyzer to perform flow analysis. The measurement chart is shown in Figure 7.

[0096] From Figure 7, it was found that ammonia nitrogen and nitrate nitrogen were measured as the same peak. From this result, it was found that both ammonia nitrogen and nitrate nitrogen were oxidized to nitric acid by potassium peroxodisulfate, and reduced to ammonia by passing through the reduction section, and were accurately measured. It was confirmed that when this flow analyzer and method were applied, there was no difference in the nitrogen content measurement results due to differences in the state of nitrogen.

[0097] [Example 3: Comparison with conventional methods] To ensure compatibility with the naphthylethylenediamine spectrophotometric method using a copper-cadmium coil (hereafter referred to as the conventional method) in total nitrogen measurement, the same samples were measured and the results were compared. The samples used were river water, stream water, pond water, industrial water, surplus water, flue gas scrubbing equipment: industrial wastewater, inflow water, wastewater treatment tank: industrial wastewater, groundwater, activated ion water, leachate, aeration tank No. 1: industrial wastewater, within the factory: discharge water, seawater, and treated water. The results are shown in Table 1.

[0098] [Table 1]

[0099] As shown in Table 1, the measurement results of this method and the conventional method were comparable. These results demonstrate that this method, like the conventional method, is capable of measuring total nitrogen in wastewater and environmental water. [Industrial Applicability]

[0100] According to the present invention, it is possible to provide an apparatus and method for continuously analyzing total nitrogen in a sample with high measurement accuracy without using cadmium, which causes environmental pollution.

[0101] This configuration can reduce the burden on the environment, thereby contributing to the achievement of Goals 14 and 15 of the Sustainable Development Goals (SDGs). [Explanation of symbols]

[0102] 1 Sample introduction section 2. Reduction section 3 Analysis Department 4 Bubble segment 5 Reagent introduction section 6 Gas permeable section 7 Conduit 8 Carrier Introduction 9 Heating tank 10 Flow Cell 11 Mixing coil 12 PTFE porous filter 13 Pretreatment section 14 Ammonia gas absorption section

Claims

1. A sample introduction section for introducing a sample into a pipeline; a pretreatment section for converting all nitrogen in the sample into nitrate ions; a reduction section for reducing nitrate ions in the sample pretreated in the pretreatment section and transported through the pipeline to ammonium ions; a gas permeation section for gasifying and separating the ammonium ions generated in the reduction section; an ammonia gas absorption section in which the gaseous ammonia that has permeated the gas permeation section is absorbed by a receiving reagent to convert the gaseous ammonia into ammonium ions; An analysis unit that analyzes ammonium ions in a receiving reagent containing ammonium ions transported through a pipeline, The reduction section is a hollow tube having at least an inner wall surface made of zinc, and includes a reduction member through which a sample is transported.

2. The analytical device of claim 1 , wherein the hollow tube is in the shape of a helix or a figure-of-eight helix.

3. 2. The analytical device according to claim 1, wherein at least an inner wall surface of the hollow tube is coated with copper.

4. 10. The analyzer of claim 1 which is a flow analyzer.

5. The analytical device according to any one of claims 1 to 4, further comprising a bubble segmentation section that performs bubble segmentation on a sample introduced into the pipeline, thereby creating a plurality of segments within the pipeline that are partitioned by bubbles.

6. The analytical device of claim 5 , wherein the gas bubbles are nitrogen, argon, or helium.

7. The analytical device according to any one of claims 1 to 4, further comprising a reagent introduction section for introducing a reagent for quantifying ammonium ions generated in the ammonia gas absorption section by an indophenol blue absorptiometry method using salicylic acid.

8. 5. The analytical device according to claim 1, further comprising a chelating agent introduction section for adding a chelating agent to the sample to capture metal ions.

9. The analytical device of claim 8 , wherein the chelating agent is ethylenediaminetetraacetic acid (EDTA).

10. 5. The analytical device according to claim 1, wherein the gas permeable membrane provided in the gas permeable portion is a PTFE porous filter.

11. A sample introduction step of introducing a sample into a pipeline; A pretreatment step of converting all nitrogen in the sample into nitrate ions; a reduction step of reducing nitrate ions in the sample pretreated in the pretreatment step and transported through the pipeline to ammonium ions; a gas permeation step for gasifying and separating the ammonium ions produced in the reduction step; an ammonia gas absorption step in which the gaseous ammonia separated in the gas permeation step is absorbed by a receiving reagent to convert it into ammonium ions; and an analysis step of analyzing ammonium ions in a receiving reagent containing ammonium ions transported through the pipeline, The reduction step of this analytical method comprises reducing nitrate ions in the sample by transporting the sample through a hollow tube having at least an inner wall surface made of zinc.

12. The analytical method according to claim 11, wherein the gasification of the ammonium ions produced in the reduction step includes making the pH of the sample alkaline by adding sodium hydroxide and boric acid.

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