Method and device for measuring concentration of trace gas component in water

Abstract

This invention provides a method and apparatus for the concentration and determination of trace gas components in water. It avoids cumbersome manual operations and improves sensitivity through sampling and concentration of sample water, and prevents the reduction of column separation performance due to large amounts of sample water. It is suitable for high-precision determination of trace gas components present in ultrapure water and other water. The present invention is characterized by: an introduction means for introducing a predetermined amount of water to be measured into the flow path of the measuring means; a gas-water separation means for separating the water to be measured, which has been introduced into the aforementioned flow path of the measuring means, into the aforementioned trace gas components and water by means of a pre-column; a concentration means for cooling and concentrating the aforementioned trace gas components separated from the water, and for heating the concentrated aforementioned trace gas components and sending them out to the main column section; an oxygen removal means for removing oxygen from the sent-out aforementioned trace gas components; a gas component separation means for separating the aforementioned trace gas components after oxygen removal into one or more gas components other than the aforementioned oxygen component by means of means of the aforementioned main column section; and a detection means for detecting the one or more aforementioned gas components obtained after separation.

Description

Technical Field

[0001] This invention relates to a method and apparatus for the concentration and determination of trace gaseous components in water, for example, to a method and apparatus suitable for the high-precision determination of trace gaseous components present in ultrapure water. Prior Technology

[0002] Ultrapure water is generally used for cleaning semiconductor wafers and liquid crystals, steam generators in power plants' turbines for stable operation, and injection water in the pharmaceutical industry where safety is paramount in all situations. Depending on the application, even trace amounts of impurities must be removed. Impurities, as referred to here, include all substances other than H₂O, such as gases, microparticles, metal ions, inorganic substances, and organic substances.

[0003] Gas chromatography has been used as a method for determining trace impurities, especially gaseous components, that exist in water due to mixing or dissolving in it.

[0004] Furthermore, various methods have been proposed for determination using gas chromatography (for example, see Patent Document 1). [Previous Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Re-appearance No. 2014-109410 Summary of the Invention

[0006] [The problem that the invention aims to solve]

[0007] However, there are problems with the determination of trace gas components in water using conventional gas chromatography.

[0008] In recent years, the concentration of gases in water, such as ultrapure water which requires the management of dissolved gases, has sometimes reached extremely low levels, ranging from tens to several ppb. Directly measuring this concentration using existing gas chromatography instruments is not feasible due to their sensitivity.

[0009] Furthermore, for example, when a small amount (less than a few μL) of sample water containing trace gas components is directly injected into the analytical column using a microsyringe and then measured, water will slowly remain and accumulate in the analytical column. When the accumulated water reaches a level that affects separation, the column temperature is increased to allow for aging, restoring the column's activity and enabling further analysis. However, this method has the following drawbacks: because the injected volume into the analytical column is very small, it is impossible to measure gas components at the aforementioned trace concentrations. Specifically, the measurable range is limited to a lower limit of approximately ppm, and it is impossible to measure trace gas components in water below ppm.

[0010] Alternatively, some researchers have performed concentration determination methods using headspace or purge-trap methods.

[0011] For example, in the concentration and determination of trace VOCs (volatile organic compounds) in water using a blow-and-capture method, the sample water is sealed directly into a small glass bottle containing a large amount of air in the gas phase. The gas or liquid phase containing this air is then bubbled with a passive gas to expel and capture the VOC components, which are then measured using GC-MS (gas chromatography-mass spectrometry) or GC-FID (gas chromatography with a flame ionization detector). However, the GC-MS or GC-FID used in this determination cannot detect air components due to the characteristics of the detector.

[0012] Furthermore, especially when determining argon in gas components, if oxygen from the air is mixed in, argon and oxygen cannot be separated under normal analytical conditions. Therefore, it is important to avoid mixing in air components during the sampling process.

[0013] Furthermore, the method proposed in the aforementioned Patent Document 1, which uses a vacuum gas sampling bottle to sample dissolved gas through a diaphragm and introduces it into a gas chromatography instrument, cannot avoid the mixing of air components, so it cannot determine trace amounts of argon in water.

[0014] Therefore, this measurement method, which cannot avoid the mixing of ambient gases (air components) during pretreatment, is inconvenient for measuring trace amounts of argon in water when the mixed gas component in the water is argon.

[0015] In this case, when the object of measurement is trace gas components in water, the existing technology has the following inconveniences: it is difficult to prevent the mixing of ambient air, it is difficult to measure the correct concentration, it is necessary to calculate the recovery rate obtained by bubbling and blowing, and the operation is very cumbersome and complicated, thus requiring the operator's skill.

[0016] This invention addresses these problems and aims to provide a method and apparatus for the concentration and determination of trace gas components in water. It avoids cumbersome manual operations and improves sensitivity through sample water sampling and concentration operations, while preventing the reduction of column separation performance due to large amounts of sample water. It is suitable for high-precision determination of trace gas components present in ultrapure water and other water. [Methods for solving problems]

[0017] To address the aforementioned issues, the present invention provides a method for the concentration and determination of trace gas components in water in the first state sample. This method utilizes a gas chromatography instrument to determine the concentration of trace gas components present in water. The method is characterized by sequentially performing an introduction step, a gas-liquid separation step, a concentration step, a discharge step, an oxygen removal step, a gas component separation step, and a detection step to determine the concentration of the aforementioned trace gas components in water. Specifically, the introduction step involves introducing a predetermined amount of water containing the aforementioned trace gas components into the aforementioned measuring instrument; the gas-liquid separation step involves separating the water already introduced into the aforementioned measuring instrument... The water to be measured is separated into the aforementioned trace gas components and water by a pre-column; the concentration step involves cooling and concentrating the aforementioned trace gas components separated from the water; the discharge step involves heating the concentrated aforementioned trace gas components and discharging them into the main column section; the oxygen removal step removes oxygen from the discharged aforementioned trace gas components; the gas component separation step separates one or more gas components other than the aforementioned oxygen component from the aforementioned trace gas components after oxygen removal by the aforementioned main column section; the detection step detects the one or more aforementioned gas components obtained after separation.

[0018] The present invention is constructed in this manner, so it can avoid tedious manual operations and can improve the sensitivity by means of sampling method of sample water (i.e., the water to be measured) and concentration operation, and prevent the deterioration of column separation performance caused by large amount of sample water, so as to determine trace gas components in water such as ultrapure water with high precision.

[0019] Furthermore, the method for concentrating and determining trace gas components in water in the second state of the present invention is characterized in that: in the first state of the sample, in terms of the aforementioned introduction step, a predetermined amount of the water to be measured, which has been filled into a metal sample cylinder or flexible container, is introduced into the aforementioned measuring means in a state in which it has been separated from the outside air, and the method includes a step of causing the purge gas to flow countercurrently in the aforementioned pre-column section to discharge the water separated in the aforementioned gas-water separation step outside the aforementioned measuring means.

[0020] The present invention is constructed in this way, so the introduction of the water to be measured into the measuring device can be performed in a state of isolation from the outside, and the residual water in the pre-column can be reliably discharged to the outside of the measuring device, enabling the high-precision measurement of trace gas components present in water such as ultrapure water.

[0021] Furthermore, the method for concentration and determination of trace gas components in water in the third state of the present invention is characterized in that: in the first or second state of the sample, the trace gas components determined in the aforementioned detection step are one or more of argon, methane, carbon monoxide, carbon dioxide, krypton, and xenon.

[0022] This invention is constructed in this manner, so it can reliably determine the composition of specific types of gases such as argon with high precision.

[0023] The first state of the present invention, a device for concentrating and measuring trace gas components in water, uses a gas chromatography method to measure the concentration of trace gas components present in water. It is characterized by comprising: an introduction means for introducing a predetermined amount of water to be measured into the flow path of the aforementioned measuring means; a gas-water separation means for separating the water to be measured, already introduced into the aforementioned flow path of the aforementioned measuring means, into the aforementioned trace gas components and water using a pre-column; a concentration means for cooling and concentrating the aforementioned trace gas components separated from the water, and for heating the concentrated aforementioned trace gas components and sending them to the main column; an oxygen removal means for removing oxygen from the sent-out aforementioned trace gas components; a gas component separation means for separating the aforementioned trace gas components after oxygen removal into one or more gas components other than the aforementioned oxygen component using the aforementioned main column; and a detection means for detecting the one or more aforementioned gas components obtained after separation.

[0024] The present invention is constructed in this manner, so by using the apparatus of the present invention in the first state sample to perform the method of the present invention in the first state sample, tedious manual operation can be avoided, and measures can be taken to improve the sensitivity by means of sampling method of sample water (i.e., water to be measured) and concentration operation, and to prevent the reduction of column separation performance due to a large amount of sample water, so as to determine trace gas components present in ultrapure water and other water with high precision.

[0025] Furthermore, the device for concentrating and measuring trace gas components in water in the second state of the present invention is characterized in that: in the first state of the sample, the aforementioned introduction means is a metal sample cylinder or flexible container that can be filled with a predetermined amount of the water to be measured, and is configured to connect it to the aforementioned flow path and introduce the water to be measured into the aforementioned flow path in a state that has been separated from the outside air; the aforementioned gas-water separation means is configured to cause the purge gas to flow countercurrently in the aforementioned pre-column section and discharge the separated water to the outside of the aforementioned measuring means.

[0026] The present invention is constructed in this manner, so by using the apparatus of the present invention in the second state to perform the method of the present invention in the second state, the introduction of the water to be measured into the measuring apparatus can be performed in a state isolated from the outside, and the residual water in the pre-column can be reliably discharged to the outside of the measuring apparatus, enabling the high-precision measurement of trace gas components present in water such as ultrapure water.

[0027] Furthermore, the apparatus for concentrating and measuring trace gas components in water in the third state of the present invention is characterized in that: in the first or second state of the present invention, the aforementioned flow path is formed such that the aforementioned water to be measured, the separated trace gas components, the water, and the concentrated trace gas components can be transported by a working gas supplied from outside the aforementioned measuring means to the aforementioned flow path and a switching valve provided in the aforementioned flow path.

[0028] The present invention is constructed in this manner, so the connection state of the flow path can be switched by switching valve according to the purpose, and trace gas components can be measured with good operating efficiency.

[0029] Furthermore, the apparatus for concentrating and measuring trace gas components in water in the fourth state of the present invention is characterized in that: in any of the first to third state samples, the trace gas components measured in the aforementioned detection means are one or more of argon, methane, carbon monoxide, carbon dioxide, krypton, and xenon.

[0030] The present invention is constructed in this manner, so by using the apparatus of the present invention in the fourth state to perform the method of the present invention in the third state, it is possible to reliably determine trace gas components of a specific type with high precision. [Effects of the Invention]

[0031] As described above, the present invention provides a method and apparatus for the concentration and determination of trace gas components in water, which avoids tedious manual operations and improves sensitivity through the sampling method and concentration operation of the sample water, and prevents column deterioration caused by a large amount of sample water, thus making it suitable for high-precision determination of trace gas components present in water such as ultrapure water. Simple Explanation of the Diagram

[0032] [Figure 1] is a block diagram showing the overall structure of one embodiment of the present invention. [Figure 2] is a block diagram showing the overall structure of another embodiment of the present invention. [Figure 3] is a characteristic graph showing the chromatographic data of standard gases measured by the present invention. [Figure 4] is a characteristic graph showing the chromatographic data of the gas present in the water 1 being measured by means of the present invention. [Figure 5] is a characteristic graph showing the chromatographic data of the gas present in the water sample 2 measured by the present invention. Implementation

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to Figures 1 and 2.

[0034] Figure 1 shows the overall configuration of one embodiment of the device for concentrating and measuring trace gas components in water according to the present invention.

[0035] The water trace gas component concentration and determination device 1 of this embodiment is configured such that the water to be measured is introduced into the determination device 3, which is the determination device, through the introduction unit 2 (shown on the left side of Figure 1), and the concentration of trace gas components in the water is determined by the gas chromatography instrument 4 of the determination device 3. Furthermore, it is configured such that the components from the introduction unit 2 to the gas chromatography instrument 4 are sequentially connected in a flow path F for the flow of the water and gas components to be measured, and the flow state is controlled by switching valves V1 to V4 installed along the path.

[0036] The following sections will explain the constituent parts in order from upstream to downstream.

[0037] The inlet unit 2 is configured to allow the metal sample cylinder 5, which stores the water to be measured due to the presence of trace gas components, to be freely installed in the flow path F1, and has stop valves ST1 to ST4 for controlling the flow of the water to be measured during the inlet on the upstream and downstream sides of the flow path F1.

[0038] The flow path F1 of the inlet unit 2 is connected to the flow path F2 of the measuring device 3. The flow path F2 is connected to the measuring tube 6, which measures the amount of water to be measured, through the switching valve V1. Downstream of switching valve V1, a gas-liquid separation unit 8 is connected via flow path F3 and switching valve V2. This gas-liquid separation unit 8 is a separation means that includes a pre-column 7 and separates the water to be measured into water and trace gas components. Switching valve V2 is connected to a flow path FPG1 for supplying purge gas PG1 and a discharge flow path P1 for discharging water. The purge gas PG1 is used as a working gas to backflow and discharge any water remaining in the pre-column 7. Furthermore, switching valve V1 is connected to a discharge flow path P2 for discharging excess water when measuring the water to be measured in the metering tube 6. Downstream of the gas-liquid separation unit 8, a capture tube 9 is connected via a switching valve V2, a flow path F4, and a switching valve V3. This capture tube 9 serves as a concentration means to cool and concentrate trace gas components separated from the water, and to heat the concentrated trace gas components before sending them to the main column section 4a. A heater 10 for heating is wound around the outside of this capture tube 9. A Dewar flask 11 storing liquid nitrogen is arranged above the capture tube 9 in a manner that allows it to move freely up and down.

[0039] Downstream of the capture tube 9, a gas chromatograph 4 is connected via a switching valve V3, a flow path F5, a switching valve V4, and a flow path F6. A flow path FCG for supplying carrier gas CG is connected to the switching valve V4. This carrier gas CG is used as the working gas to transport the concentrated trace gas components in the capture tube 9 to the gas chromatograph 4.

[0040] An oxygen trap 12 is connected to flow path F6. The oxygen trap 12 is used as an oxygen removal means to remove oxygen from trace gas components.

[0041] A main column section 4a is connected downstream of the oxygen trap 12. This main column section 4a serves as a gas component separation method for separating various gas components other than the oxygen-removed components from the trace gas components after oxygen removal. A detector 13 is connected downstream of the main column section 4a. This detector 13 serves as a detection method for detecting the various gas components obtained after separation.

[0042] The system is configured such that the chromatographic signal is transmitted from the detector 13 to the data processing device 14, i.e., the PC (personal computer) 15 (hereinafter referred to as "PC15"). The concentration of the gas components obtained by the PC15 is displayed on a display device (not shown) or printed. Furthermore, the PC15 transmits sequential control signals to the control unit 16 to control the up and down movement of each switching valve V1~V4, the capture tube 9, the heater 10, and the Dewar flask 11.

[0043] Next, a method for the concentration and determination of trace gaseous components in water according to this embodiment will be described.

[0044] In this embodiment, the gas present in the water due to mixing in will be described as argon.

[0045] <Import Steps> In the import step, a predetermined amount of the water to be measured, which contains trace gas components due to their mixing, is introduced into the measuring device 3, which serves as the measuring means.

[0046] Specifically, first, the water to be measured is sealed in a metal sample cylinder 5 with an internal volume of about 1L in a way that prevents air components from entering, and then it is connected to the flow path F1 of the inlet unit 2.

[0047] Next, place sample cylinder 5 vertically and connect it to purge gas PG2 (high-purity helium (He)) via the upper stop valve ST1. With stop valve ST3 closed, alternately open and close both stop valves ST1 and ST2 several times to replace the air in flow path F1 with helium. Then, fine-tune both stop valves ST1 and ST2 to ensure a continuous helium flow of approximately 100-500 ml / min.

[0048] Then, carefully open and adjust the other stop valves ST3 and ST4 to allow the water to be measured to flow through the lower flow paths F1 and F2 into the measuring tube 6. The amount of water to be measured reduced in the metal sample cylinder 5 will be filled by helium, so the metal sample cylinder 5 will not become negatively pressured. Alternatively, the helium can be slightly pressurized to squeeze out the water to be measured and introduce it into the measuring tube 6.

[0049] Next, the switching valve V1 is operated to purge the water to be measured in the metering tube 6 with purge gas PG1 (high purity helium (He)) and introduce it into the pre-column 7.

[0050] Here, the metering tube 6 has an internal volume of approximately 200 μL, which is relatively large for the liquid introduction volume of a gas chromatograph. It is directly connected to the metering tube 6 and circulated with water to prevent contamination by air components during sampling. Moreover, the amount of water to be measured is approximately 100 times the sample volume of the usual measurement level, thus enabling highly sensitive measurement.

[0051] <Gas-Liquid Separation Steps> In the gas-water separation step, the water to be measured, which has been introduced into the gas-water separation unit 8, is separated into trace gas components and water by the pre-column 7.

[0052] Specifically, the gaseous components containing argon and moisture are separated in the pre-column 7, and the argon is introduced into the capture tube 9, which is cooled by liquid nitrogen in the Dewar flask 11. On the other hand, when moisture remains in the pre-column 7, the switching valve V2 is operated to reverse the flow direction of the purge gas PG1 in the pre-column 7, so that the moisture is discharged outside the pre-column 7 through the switching valve V2 and the discharge flow path P1.

[0053] Here, draining the water outside the pre-column 7 protects it from reduced separation performance caused by a large amount of water remaining inside, thus shortening the analysis time.

[0054] <Concentration Steps> In the concentration step, liquid nitrogen is used to cool and concentrate the trace gaseous components separated from the water.

[0055] Specifically, the Dewar flask 11 is raised so that the capture tube 9 is immersed in liquid nitrogen, thereby causing the trace gas components in the capture tube 9 to condense and be concentrated and collected.

[0056] Here, the trace gas components that have been separated from moisture by the pre-column 7 are injected in large quantities, so the peaks tend to broaden in the main column 4a. Therefore, if the trace gas components are introduced into the capture tube 9, which is cooled with liquid nitrogen, and concentrated and collected, the bandwidth of the measured components will narrow, and they will be detected with a sharp peak shape when introduced into the main column 4a.

[0057] The trapping tube 9 is formed by shaping a Sulfinert tube with an inner passivated surface into a U-shape, winding it around a heater 10, and filling it with an adsorbent filler. Before the measurement begins, a small Dewar flask 11 containing liquid nitrogen is raised to immerse and cool the trapping tube 9 in the liquid nitrogen. After collecting trace amounts of gas components that are to be measured, the Dewar flask 11 is lowered to extract the trapping tube 9 from the liquid nitrogen. The heater 10 is then energized and heated. The collected trace amounts of gas components are driven out by the carrier gas CG and sent to the main column 4a.

[0058] <Send-out steps> In the delivery step, the trace gas components, which have been concentrated in the capture tube 9, are heated and delivered to the main column section 4a.

[0059] Specifically, at the point when the concentration and collection by the capture tube 9 ends, the connection state of the switching valves V3 and V4 is adjusted so that the gas chromatography carrier gas (He) CG is sent to the capture tube 9 through the flow path FCG, the switching valve V4, the flow path F5a, and the switching valve V3. Then, through the capture tube 9 and the switching valve V3, the flow path F5 and F6 are switched towards the gas chromatography instrument 4.

[0060] Next, the Dewar flask 11 filled with liquid nitrogen is lowered to lift the capture tube 9 from the liquid nitrogen, and then the heater 10 is energized to heat the capture tube 9.

[0061] In this way, the trace gaseous component, namely argon, obtained by cooling and capturing with liquid nitrogen, is driven out while the capture tube 9 is heated and sent to the gas chromatography instrument 4 in sequence through switching valve V3, flow path F5, switching valve V4, and flow path F6.

[0062] <Oxygen Removal Steps> In the oxygen removal step, oxygen is removed from the trace gas components that have been sent out from the capture tube 9.

[0063] Specifically, oxygen is removed by adsorption and capture of trace gas components introduced into the oxygen trap 12 through the flow path F6 and by the carrier gas CG.

[0064] Here, the separation of oxygen and argon by the oxygen trap 12 involves introducing a trace amount of gas into the oxygen trap 12 to adsorb and remove the oxygen, while only allowing argon to be detected. The oxygen trap 12 is a commercially available product, and its efficiency will decrease if it adsorbs a large amount of oxygen, but its oxygen adsorption capacity is in the L (liter) range. In contrast, the oxygen in the trace gas component that is the subject of this invention is in the ppm level, so there is almost no need to perform aging and regeneration of the oxygen trap 12.

[0065] <Gas Component Separation Steps> In the gas component separation step, the trace gas components after oxygen removal are separated into multiple gas components other than oxygen components by the main column section.

[0066] Specifically, the trace gaseous components after oxygen removal are separated into argon, nitrogen, and other gaseous components in the main column section 4a.

[0067] Here, under normal conditions, the gas components introduced into the main column section 4a will separate into argon + oxygen and nitrogen, with argon and oxygen not separated and detected as a single peak. In contrast, in this invention, an oxygen trap 12 is provided upstream of the main column section 4a, so oxygen is adsorbed and captured by the oxygen trap 12, and therefore, argon is detected as a separate peak.

[0068] <Detection Steps> In the detection process, various gaseous components that have undergone oxygen removal in the preceding stage are detected.

[0069] Specifically, a detector 13, consisting of a thermal conductivity detector and the like, is used to detect various gas components. The gas supplied for this detection is then discharged outside the concentration and measurement device 1.

[0070] The detection results are output via the data processing device 14, i.e., PC 15, and displayed on a monitor (not shown) or printed out.

[0071] The above measurement method is executed automatically by PC15 and control unit 16. Alternatively, it can be executed manually.

[0072] The measurement method according to this embodiment avoids tedious manual operations and can improve sensitivity by using sampling methods and concentration operations for the water to be measured as sample water, and prevent column deterioration caused by large amounts of sample water. Thus, it can measure trace gas components present in water such as ultrapure water with high precision.

[0073] Next, the implementation shown in Figure 2 will be explained.

[0074] Figure 2 shows the overall configuration of another embodiment of the device for concentrating and measuring trace gas components in water according to the present invention.

[0075] Compared with the embodiment shown in Figure 1, this embodiment differs in that the introduction unit 2, which serves as the means of introducing the water to be measured into the measuring device 3, has been modified. All other components remain unchanged and are therefore referred to by the same symbols.

[0076] In this embodiment, a flexible container 25 (such as a medical infusion bag) is used instead of the metal sample cylinder 5 of the aforementioned embodiment. This prevents air from entering the flexible container 25, allowing only the water to be measured to be sampled. Furthermore, the flexible container 25 is connected to a flow path F1 that communicates with the flow path F2 of the measuring device 3, and is housed within a pressurized housing 26. Stop valves ST1 and ST2 are installed upstream and downstream of the flexible container 25 in the flow path F1, respectively.

[0077] Next, the measurement method according to this embodiment will be explained.

[0078] <Import Steps> The importing step involves introducing a predetermined amount of the water to be measured, which contains trace amounts of gaseous components, into the measuring device 3, which serves as the measuring instrument.

[0079] Specifically, first, the water to be measured is sealed in a flexible container 25 with an internal volume of about 1L in a manner that prevents air components from entering, and then it is connected to the flow path F1 of the inlet unit 2.

[0080] Then, carefully open the stop valves ST1 and ST2, and use the purge gas PG2 (the type of purge gas is not important, but He is recommended to prevent contamination) to squeeze the flexible container 25 from the outside with slight pressure, so that the water to be measured is squeezed to the downstream side of the flow path F1, and then introduced into the metering tube 6 through the flow path F2.

[0081] In addition to the above, it can also be adjusted to: the flexible container 25 is placed above the measuring device 3, and the water to be measured passes through the downstream flow paths F1 and F2 due to its own weight and enters the measuring tube 6.

[0082] <Gas-Liquid Separation Steps> to <Detection Steps> It is performed in exactly the same manner as the <gas-liquid separation step> to <detection step> in the aforementioned implementation form, so the description is omitted.

[0083] Furthermore, this embodiment can achieve the same effect as the aforementioned embodiments, so the description is omitted.

[0084] <Example> Next, an embodiment of the concentration measurement performed by the water trace gas component concentration measurement device 1 of the present invention, as shown in Figure 1 or Figure 2, will be described. Since the same procedure is performed in both figures, the following description will focus on an embodiment of the concentration measurement performed by the water trace gas component concentration measurement device 1 shown in Figure 1.

[0085] Determination of Standard Gases Before measuring the water to be tested, the aforementioned <Introduction Step> to <Detection Step> are performed on a standard gas containing a predetermined amount of argon and helium.

[0086] Specifically, the standard gas Ar 1000ppm / He is connected to flow path F2 and loaded into metering tube 6 of switching valve V1. Then, all steps from <Introduction Step> to <Detection Step> are performed sequentially to conduct the measurement. In addition, 0.3324 μg of standard gas Ar 1000ppm / He is loaded into a 200 μL metering tube at 20°C and 1 atmosphere.

[0087] The measurement results obtained by detector 13, i.e., chromatographic data, are processed by data processing device 14, i.e., PC (personal computer) 15, and displayed on a display device (not shown) or printed out in the form of standard gas chromatographic data as shown in Figure 3. As shown in Figure 3, argon 0.3324 μg was measured at a position of 6.062 minutes with a height of 2518 μV. The oxygen peak position overlaps with the argon peak position, but the standard gas does not contain oxygen, so the reliability of the argon measurement results shown in Figure 3 becomes extremely high. Furthermore, even if the standard gas contains oxygen, in this embodiment, oxygen is reliably removed in the <oxygen removal step>, so the oxygen peak is not measured, and the high reliability of the argon measurement results is still maintained. This argon measurement result is used as the reference for the subsequent measurement of argon in the water being measured.

[0088] <Determination of Water 1 being measured> Prepare a liquid containing trace amounts of argon in ultrapure water without degassing treatment as the test water 1, and perform the aforementioned <Introduction Step> to <Detection Step>.

[0089] Specifically, the water to be measured 1 is prepared and supplied to a metal sample cylinder 5, and then all steps from the <Introduction Step> to the <Detection Step> are performed in sequence to carry out the measurement.

[0090] The measurement results obtained by detector 13, i.e., chromatographic data, are processed by data processing device 14, i.e., PC (personal computer) 15, and displayed on a display device (not shown) or printed out in the form of chromatographic data of trace gases present in the water 1 being measured, as shown in Figure 4. As shown in Figure 4, argon was detected as a peak at a residence time of 5.897 minutes and a height of 360 μV, and its concentration was measured to be 0.0407 μg (equivalent to 203.5000 ppb in water). The residence time of the argon peak in the water 1 being measured, 5.897 minutes, is consistent with the residence time of the argon peak in the standard gas, 6.062 minutes, indicating high reliability of the argon measurement results shown in Figure 4. Moreover, although the argon content is at the trace level of ppb, it is still accurately measured. Furthermore, regarding the oxygen present in the water being measured 1, in this embodiment, oxygen is reliably removed during the <oxygen removal step>, so the oxygen peak will not be measured, maintaining a high reliability of the argon measurement results. In Figure 4, the peak to the right of argon represents nitrogen.

[0091] <Measurement of Water Subject 2> Prepare a liquid containing trace amounts of argon that has undergone degassing treatment in ultrapure water as the water to be measured, and perform the aforementioned <Introduction Step> to <Detection Step>.

[0092] Specifically, the water to be measured 2 is prepared and supplied to the metal sample cylinder 5, and then all steps from the <Introduction Step> to the <Detection Step> are performed in sequence to carry out the measurement.

[0093] The measurement results obtained by detector 13, i.e., chromatographic data, are processed by data processing device 14, i.e., PC (personal computer) 15, and displayed on a display device (not shown) or printed out in the form of chromatographic data of trace gases present in the water 2 being measured, as shown in Figure 5. As shown in Figure 5, argon is detected as a peak at a residence time of 5.925 minutes and a height of 44 μV, and its concentration is measured to be 0.0047 μg (equivalent to 23.5000 ppb in water). The residence time of the argon peak in the water 2 being measured, 5.925 minutes, is consistent with the residence time of the argon peak in the standard gas, 6.062 minutes, indicating high reliability of the argon measurement results shown in Figure 5. Moreover, although the argon content is at the trace level of ppb, it is still accurately measured. Furthermore, regarding the oxygen present in the water 2 being measured, in this embodiment, oxygen is accurately removed in the <oxygen removal step>, so the oxygen peak is not measured, maintaining high reliability of the argon measurement results. In Figure 5, the peak to the right of argon represents nitrogen.

[0094] As shown in the measurement results of the various embodiments in Figures 4 and 5, the water trace gas component concentration and measurement device 1 according to the present invention can reliably measure the trace gas, namely argon (ppb level content), contained in the water samples 1 and 2 without being affected by oxygen, and the reliability is also very high.

[0095] Furthermore, the present invention is not limited to the aforementioned embodiments and various modifications can be made. For example, in terms of the introduction method, the metal sample cylinder 5 and the flexible container 25 may not be used, but instead a flow path F2 is formed to transport the water to be measured to the measuring device 3 online through a flow path F1.

[0096] 1: Apparatus for Concentration and Determination of Trace Gas Components in Water 2: Import Unit 3: Measuring device 4: Gas Chromatography 4a: Main Column 5: Metal sample cylinder 6: Metering tube 7: Pre-cast tubing 8: Gas-water separation unit 9: Capture tube 10: Heater 11: Dewar bottle 12: Oxygen trap 13: Detector 14: Data processing device 15: PC (Personal Computer) 16: Control Unit 25: Flexible container 26: Pressurized housing CG: Carrier Gas F,F1,F2,F3,F4,F5,F5a,F6,FCG,FPG1: flow path P1, P2: discharge flow path PG1, PG2: Purge gases ST1, ST2, ST3, ST4: Stop valves V1, V2, V3, V4: Switching valves

Claims

1. A method for the concentration and determination of trace gaseous components in water, comprising using a gas chromatography instrument to determine the concentration of trace gaseous components present in water, characterized by: determining the concentration of the trace gaseous component present in water by sequentially performing an introduction step, a gas-liquid separation step, a concentration step, a discharge step, an oxygen removal step, a gas component separation step, and a detection step; wherein, The introduction step involves introducing a predetermined amount of water containing the trace gas component into the measuring instrument; the gas-water separation step involves separating the water into the trace gas component and water using a pre-column; the concentration step involves cooling and concentrating the trace gas component separated from the water; the discharge step involves heating the concentrated trace gas component and discharging it into the main column section; the oxygen removal step involves removing oxygen from the discharged trace gas component; the gas component separation step involves separating one or more gas components other than oxygen from the oxygen-removed trace gas component using the main column section; the detection step involves detecting one or more of the separated gas components; the trace gas component detected in the detection step includes argon.

2. The method for concentration and determination of trace gaseous components in water as requested in item 1, wherein, Regarding the introduction step, it is configured to introduce a predetermined amount of the water to be measured into the measuring means in a state that has been separated from the outside air, and to cause the purging gas to flow countercurrently in the pre-column section, thereby discharging the water separated in the gas-water separation step outside the measuring means.

3. The method for concentration and determination of trace gaseous components in water as requested in item 1 or 2, wherein, The trace gaseous components measured in this detection step further include one or more of methane, carbon monoxide, carbon dioxide, krypton, and xenon.

4. A device for concentrating and measuring trace gas components in water, which uses a gas chromatography method to determine the concentration of trace gas components present in water, characterized by comprising: an introduction method for introducing a predetermined amount of water to be measured into the flow path of the measuring method; a gas-water separation method for separating the water to be measured, which has been introduced into the flow path of the measuring method, into the trace gas components and water by a pre-column; a concentration method for cooling and concentrating the trace gas components separated from the water, and heating the concentrated trace gas components and sending them out to the main column section; an oxygen removal method for removing oxygen from the sent trace gas components; a gas component separation method for separating the oxygen-removed trace gas components into one or more gas components other than the oxygen component by the main column section; and a detection method for detecting the one or more gas components obtained after separation; wherein the trace gas component detected by the detection method includes argon.

5. The apparatus for concentrating and measuring trace gaseous components in water as described in claim 4, wherein, The introduction means is a metal sample cylinder or flexible container that can be filled with a predetermined amount of the water to be measured, and is configured to connect it to the flow path and introduce the water to be measured into the flow path in a state that has been separated from the outside air. The gas-water separation means is configured to cause the purging gas to flow countercurrently in the pre-column section and discharge the separated water to the outside of the measuring means.

6. The apparatus for concentrating and measuring trace gaseous components in water as described in claim 4 or 5, wherein, The flow path is configured to transport the water to be measured, the separated trace gas components, the water, and the concentrated trace gas components by means of a working gas supplied from outside the measuring instrument and a switching valve installed in the flow path.

7. The apparatus for concentrating and measuring trace gaseous components in water as described in claim 4 or 5, wherein, The trace gaseous components measured in this detection method further include one or more of methane, carbon monoxide, carbon dioxide, krypton, and xenon.

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