Method and apparatus for measuring the concentration of trace gaseous components in water.

Abstract

To provide a concentration measurement method and device of an underwater trace gas composition suitable for highly accurately measuring a trace gas composition existing in the water like ultra pure water.SOLUTION: A concentration measurement device of an underwater trace gas composition comprises: introduction means which introduces a prescribed amount of measurement object water into a flow passage of measurement means; gas-water separation means which separates the measurement object water introduced into the flow passage of the measurement means to the trace gas composition and water with a precolumn; concentration means which cools the trace gas composition separated from the water to concentrate it and warms the concentrated trace gas composition to feed it to a main column portion; oxygen removal means which removes oxygen from the fed trace gas composition; gas composition separation means which separates the trace gas composition from which oxygen has been removed to one or plural types of gas compositions excluding the oxygen composition with the main column portion; and detection means which detects the one or plural types of separated gas compositions.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] , , , , ,

[0007] ,

[0001] The present invention relates to a method and apparatus for concentrating and measuring trace gas components in water. For example, the present invention relates to a method and apparatus for concentrating and measuring trace gas components in water, which are suitable for measuring trace gas components present in ultrapure water with high accuracy.

Background Art

[0002] Generally, ultrapure water is used for washing semiconductor wafers and liquid crystals, for generating steam in steam generators of power turbines required for stable operation of power plants, and for injection water in the pharmaceutical industry where safety is required in all scenarios. Depending on the intended use, it is necessary to remove even trace amounts of impurities. Here, impurities refer to all target substances other than H2O, such as gases, fine particles, metal ions, inorganic substances, and organic substances.

[0003] As a method for measuring trace impurities, particularly gas components, that are present by being mixed or dissolved in such water, a gas chromatography method is used.

[0004] And various proposals have been made as measurement methods using the gas chromatography method (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] Furthermore, for example, when measuring water samples containing trace gaseous components by directly injecting a small amount (a few μL or less) into an analytical column using a microsyringe, moisture gradually remains and accumulates in the analytical column. If the amount of moisture accumulated becomes sufficient to affect separation, the column temperature is increased to perform aging and regenerate the column's activity, enabling re-analysis. However, this method has the disadvantage that, because the amount injected into the analytical column is minute, it is not possible to measure the trace gaseous components present at the aforementioned minute concentrations. Specifically, the measurable range is limited to a few ppm, making it impossible to measure trace gaseous components in water below ppm.

[0009] Furthermore, concentration methods using headspace or purge-trap techniques are also employed.

[0010] For example, when concentrating and measuring trace amounts of VOCs (volatile organic compounds) in water using a purge-trap method, a large amount of air is mixed into the gas phase when the sample water is loaded into the sample vial and sealed. This air-containing gas phase or liquid phase is purged with an inert gas to expel and trap the VOC components, and then measured using a GC-MS (gas chromatograph-mass spectrometer) or GC-FID (gas chromatograph with flame ionization detector). However, due to the characteristics of the detector, the GC-MS or GC-FID used in this measurement cannot detect the air component.

[0011] Furthermore, when measuring argon, a gas component in particular, if oxygen from the air is present, argon and oxygen cannot be separated under general analytical conditions. Therefore, it is important to take measures to prevent contamination by air components during the sampling process.

[0012] Furthermore, in the vacuum gas sampling bottle method proposed in Patent Document 1, which involves collecting dissolved gas via a septum using a gas-tight syringe and introducing it into a gas chromatograph, the inclusion of air components is unavoidable, making it impossible to measure trace amounts of argon in water.

[0013] Therefore, in measurement methods where contamination with ambient gas (air components) is unavoidable during such pretreatment, there was a drawback: they could not be applied to the measurement of trace argon in water, where the gas component mixed into the water is argon.

[0014] Thus, when the target of measurement is trace gaseous components in water, existing technologies have drawbacks such as difficulty in preventing contamination by ambient air, difficulty in accurately measuring the concentration amount, and the need to calculate the recovery rate by bubbling and purging, resulting in a very complicated and multifaceted operation that requires a high level of operator skill.

[0015] This invention has been made in view of these points, and aims to provide a method and apparatus for measuring trace gas components in water with high accuracy by avoiding human complexity, improving the method of collecting sample water, increasing sensitivity through concentration operations, and preventing a decrease in column separation performance due to large amounts of sample water. [Means for solving the problem]

[0016] To solve the aforementioned problems, the first embodiment of the present invention provides a method for measuring the concentration of trace gas components in water using a gas chromatograph. , in ultrapure water Trace gaseous components present Argon as A method for measuring the concentration of trace gas components in water, wherein the water to be measured contains the trace gas components. as the ultrapure water An introduction step of introducing a predetermined amount into the measuring means, and the water to be measured introduced into the measuring means is subjected to a pre-column to remove the trace gas components. moisture A gas-water separation step that separates the gas into the water, and the moistureBy sequentially carrying out the following steps: a concentration step of cooling and concentrating the trace gas component separated from the main column; a discharge step of heating the concentrated trace gas component and sending it to the main column; an oxygen removal step of removing oxygen from the discharged trace gas component; a gas component separation step of separating the oxygen-free trace gas component into one or more types of gas components excluding the oxygen component by the main column; and a detection step of detecting the separated one or more types of gas components, Argon, as a trace gas component present in ultrapure water It is characterized by measuring concentration.

[0017] As the present invention is constructed in this manner, it avoids human complexity, improves sensitivity through sampling of the water to be measured (sample water), and prevents deterioration of column separation performance due to large amounts of sample water, thereby enabling high-precision measurement of trace gaseous components present in water such as ultrapure water.

[0018] Furthermore, the method for concentrating trace gas components in water according to the second aspect of the present invention is characterized in that, in the introduction step, a predetermined amount of the water to be measured, filled in a metal sample cylinder or flexible container, is introduced into the measuring means in a state separated from the outside air, and the method includes a step of discharging the water separated in the gas-water separation step to the outside of the measuring means by backflowing a purge gas in the pre-column portion.

[0019] As the present invention is configured in this way, the introduction of the water to be measured into the measuring device can be performed in isolation from the outside, and any moisture remaining in the pre-column can be reliably discharged outside the measuring device, enabling high-precision measurement of trace gaseous components present in water such as ultrapure water.

[0020] Furthermore, the third embodiment of the present invention, a method for measuring the concentration of trace gas components in water, is also described in the first or second embodiment, The concentration of argon in ultrapure water is less than 1 ppm. It is characterized by the following:

[0021] As mentioned above The present invention is configured in this way, Even if the argon concentration in ultrapure water is less than 1 ppm,It is possible to reliably measure gas components with high precision.

[0022] The apparatus for concentrating and measuring trace gas components in water according to the first aspect of the present invention is an apparatus for concentrating and measuring trace gas components in water that measures the concentration of argon as a trace gas component present in ultrapure water by measuring means using a gas chromatograph, and includes an introducing means for introducing a predetermined amount of the ultrapure water as the water to be measured into the flow path of the measuring means, a gas-liquid separation means for separating the water to be measured introduced into the flow path of the measuring means into the trace gas component and moisture by a pre-column, a concentrating means for cooling and concentrating the trace gas component separated from the moisture and heating the concentrated trace gas component to send it to the main column portion, an oxygen removing means for removing oxygen from the sent trace gas component, and a gas component separation means for separating the trace gas component from which oxygen has been removed into one or more types of gas components excluding the oxygen component, and a detecting means for detecting the separated one or more types of gas components, and is characterized by measuring the concentration of argon as the trace gas component present in ultrapure water. ric acid

[0023] Since the present invention is configured in this way, by executing the method of the present invention according to the first aspect by the apparatus of the present invention according to the first aspect, human complexity is avoided, measures are taken for the sampling method of the water to be measured which is the sample water, sensitivity improvement by concentration operation, and prevention of deterioration of column separation performance due to a large amount of sample water, and trace gas components present in water such as ultrapure water can be measured with high precision.

[0024] Mu [[ID=*14]]Further, the apparatus for concentrating and measuring trace gas components in water according to the second aspect of the present invention is, in the first aspect, the introducing means is a metal sample cylinder or a flexible container capable of filling a predetermined amount of the water to be measured, and is formed to introduce the water to be measured into the flow path in a state of being connected to the flow path and separated from the outside air, and the gas-liquid separation means is formed such that the separated moisture purges the gas in a countercurrent direction and discharges it outside the measuring means.

[0025]

[0025] As the present invention is configured in this way, by performing the method of the present invention according to the second embodiment using the apparatus of the present invention according to the second embodiment, the introduction of the water to be measured into the measuring device can be performed in isolation from the outside, and the moisture remaining in the pre-column can be reliably discharged outside the measuring device, and trace gaseous components present in water such as ultrapure water can be measured with high precision.

[0026] Furthermore, in the third embodiment of the present invention, the water trace gas component concentration measuring device is characterized in that, in the first or second embodiment, the flow path is formed to be able to transport the water to be measured, the separated trace gas component, water, and the concentrated trace gas component by an operating gas supplied into the flow path from outside the measuring means and a switching valve installed in the middle of the flow path.

[0027] As the present invention is configured in this way, the connection state of the flow path can be switched according to the purpose using a switching valve, and trace gas components can be measured efficiently.

[0028] Furthermore, in any of the first to third embodiments, the concentration measuring device for trace gas components in water according to the fourth embodiment of the present invention is measured by the detection means. The concentration of argon in ultrapure water is less than 1 ppm. It is characterized by the following:

[0029] As mentioned above The present invention is configured in such a way, Even if the argon concentration in ultrapure water is less than 1 ppm, It is possible to reliably and accurately measure gas components. [Effects of the Invention]

[0030] Thus, the present invention avoids human complexity, improves the method of collecting sample water, increases sensitivity through concentration, and prevents column degradation due to large amounts of sample water, thereby achieving ultrapurity water It exists in water trace gaseous components Argon as This invention provides a method and apparatus for measuring the concentration of trace gaseous components in water with high precision. [Brief explanation of the drawing]

[0031] [Figure 1] Block diagram showing the overall configuration of the first embodiment of the present invention. [Figure 2] Block diagram showing the overall configuration of another embodiment of the present invention [Figure 3] Characteristic diagram showing chromatographic data of standard gases measured according to the present invention. [Figure 4] Characteristic diagram showing chromatographic data of gas present in the water sample 1 measured according to the present invention. [Figure 5] Characteristic diagram showing chromatographic data of gas present in the water sample 2 measured according to the present invention. [Modes for carrying out the invention]

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to Figures 1 and 2.

[0033] Figure 1 shows the overall configuration of one embodiment of the water trace gas component concentration measurement device of the present invention.

[0034] The water trace gas component concentration measuring device 1 of this embodiment is configured to introduce the water to be measured from the introduction unit 2, which is the introduction means shown on the left side of Figure 1, to the measuring device 3, which is the measuring means, and to measure the concentration of trace gas components in the water to be measured by the gas chromatograph 4 of the measuring device 3. The components are connected in order from the introduction unit 2 to the gas chromatograph 4 by a flow path F that allows the water to be measured and gas components to flow, and the flow state is controlled by switching valves V1 to V4 provided along the way.

[0035] The following describes each component in order from the upstream side to the downstream side.

[0036] The introduction unit 2 is designed so that a metal sample cylinder 5, which stores the water to be measured due to the presence of trace gas components, can be detachably attached to the flow path F1, and has stop valves ST1 to ST4 on the upstream and downstream sides of the flow path F1 for controlling the flow of the water to be measured when it is introduced.

[0037] The flow path F1 of the introduction unit 2 is connected to the flow path F2 of the measuring device 3, and a measuring pipe 6 for measuring the amount of water to be measured is connected to the flow path F2 via a switching valve V1. Downstream of the switching valve V1, a pre-column 7 is provided via a flow path F3 and switching valve V2, and a gas-water separation unit 8, which is a separation means for separating the water to be measured into water and trace gas components, is connected to it. The switching valve V2 is connected to a flow path FPG1 that supplies purge gas PG1 as an operating gas to backflow discharge the water remaining in the pre-column 7, and to a discharge flow path P1 for discharging the water. Furthermore, the switching valve V1 is connected to a discharge flow path P2 for discharging excess water to be measured when measuring the water to be measured into the metering tube 6. Downstream of the gas-water separation unit 8, a trap tube 9 is connected as a concentration means. This trap tube cools and concentrates the trace gas components separated from water via a switching valve V2, a flow path F4, and a switching valve V3, and then heats 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 trap tube 9. A dua bin 11 containing liquid nitrogen is positioned relative to the trap tube 9 so as to be able to move up and down.

[0038] Downstream of the trap pipe 9, a gas chromatograph 4 is connected via switching valve V3, flow path F5, switching valve V4, and flow path F6. Switching valve V4 is connected to flow path FCG, which supplies carrier gas CG as an operating gas for supplying concentrated trace gas components in the trap pipe 9 to the gas chromatograph 4.

[0039] An oxygen trap 12 is connected to the flow path F6 as an oxygen removal means for removing oxygen from trace gas components.

[0040] Downstream of the oxygen trap 12 is a main column section 4a, which serves as a gas component separation means for separating multiple types of gas components other than oxygen from the trace gas components from which oxygen has been removed. Downstream of the main column section 4a is a detector 13, which serves as a detection means for detecting the separated multiple types of gas components.

[0041] The detector 13 is configured to transmit a chromatographic signal to the PC 15 (hereinafter referred to as "PC15") of the data processing device 14. The concentration of the gas components obtained by the PC15 calculations is configured to be displayed or printed on a display device (not shown). Furthermore, the PC15 transmits a sequence control signal to the control unit 16, which controls the up and down movement of each switching valve V1 to V4, the trap pipe 9, the heater 10, and the dua bin 11.

[0042] Next, the method for measuring the concentration of trace gaseous components in water according to this embodiment will be described.

[0043] In this embodiment, the gas present in the water is described as argon.

[0044] <Introduction process> In the introduction process, a predetermined amount of the water to be measured, which is present due to the mixing of trace gaseous components, is introduced into the measuring device 3, which serves as the measuring means.

[0045] Specifically, first, the water to be measured is sealed inside a metal sample cylinder 5 with an internal volume of approximately 1 L, ensuring that no air components enter, and then connected to the flow path F1 of the introduction unit 2.

[0046] Next, place the sample cylinder 5 vertically and connect the purge gas PG2 (high-purity helium gas (He)) to the upper stop valve ST1. With stop valve ST3 closed, alternately open and close the two stop valves ST1 and ST2 several times or more to replace the air component in the flow path F1 with helium. Then, fine-tune both stop valves ST1 and ST2 to maintain a constant flow of helium at approximately 100-500 ml / min.

[0047] Afterward, carefully open the other stop valves ST3 and ST4 to adjust the flow of the water to be measured through the lower flow paths F1 and F2 to the measuring tube 6. Since helium will replenish the amount of water to be measured in the metal sample cylinder 5, the metal sample cylinder 5 will not become negatively pressurized. Alternatively, it is also possible to push out the water to be measured by slightly pressurizing the helium and introducing it into the measuring tube 6.

[0048] Next, the switching valve V1 is operated to expel the water to be measured from the measuring tube 6 with purge gas PG1 (high-purity helium (He)) and introduce it into the pre-column 7.

[0049] Here, the measuring tube 6 has an internal volume of approximately 200 μL, which is a relatively large volume for introducing liquid into the gas chromatograph. By directly connecting and passing water through the measuring tube 6, contamination by air components during sampling is prevented, and the amount of water to be measured becomes approximately 100 times the normal measurement level, enabling high-sensitivity measurement.

[0050] <Sea water separation process> In the gas-water separation process, the water to be measured, introduced into the gas-water separation unit 8, is separated into trace gaseous components and water by the pre-column 7.

[0051] Specifically, the gaseous component containing argon and water are separated within the pre-column 7, and the argon is introduced into a trap tube 9 cooled with liquid nitrogen in the duabin 11. Meanwhile, with water remaining 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, and the water is discharged from the pre-column 7 system through the switching valve V2 and the discharge channel P1.

[0052] Here, water is discharged from the pre-column 7 system, protecting against a decrease in the separation performance of the pre-column 7 due to a large amount of water remaining inside the pre-column 7, and shortening the analysis time.

[0053] <Concentration process> In the concentration process, trace gaseous components separated from water are concentrated by cooling them with liquid nitrogen.

[0054] Specifically, by raising the Duabine 11 and immersing the trap tube 9 in liquid nitrogen, trace gaseous components inside the trap tube 9 are condensed and concentrated for collection.

[0055] Here, the trace gaseous components separated from the water in the pre-column 7 are injected in large quantities, so their peaks tend to broaden within the main column 4a. Therefore, by introducing the trace gaseous components into the trap tube 9, which has been cooled with liquid nitrogen, and concentrating and collecting them, the bandwidth of the measured components is narrowed, resulting in detection with a sharp peak shape when introduced into the main column 4a.

[0056] The trap tube 9 is made by shaping a sulfinate tube with an inert inner surface into a U-shape, wrapping a heater 10 around it, and filling it with an adsorption-type packing material. Before starting the measurement, a small duabin 11 containing liquid nitrogen is raised and the trap tube 9 is immersed in the liquid nitrogen to cool it, and after collecting the trace gas components that are the measurement components, the duabin 11 is lowered to remove it from the liquid nitrogen, and the heater 10 is energized to heat it, and the collected trace gas components are expelled by the carrier gas CG and sent to the main column 4a.

[0057] <Delivery process> In the discharge process, the trace gaseous components concentrated in the trap tube 9 are heated and then discharged to the main column section 4a.

[0058] Specifically, at the time when concentration and collection by trap tube 9 is completed, the connection status of switching valves V3 and V4 is operated to send the gas chromatograph carrier gas (He)CG through flow path FCG, switching valve 4, flow path F5a, and switching valve V3 to trap tube 9, and then through trap tube 9 and switching valve 3 to flow paths F5 and F6 leading to gas chromatograph 4.

[0059] Next, the Dua Bin 11, which is loaded with liquid nitrogen, is lowered to raise the trap tube 9 out of the liquid nitrogen, and then the trap tube 9 is heated by energizing the heater 10.

[0060] As a result, the argon, a trace gas component that was being cooled and trapped by liquid nitrogen, is expelled as the trap tube 9 heats up and is sent through the switching valve V3, the flow path F5, the switching valves V4 and F6 in sequence towards the gas chromatograph 4.

[0061] <Oxygen removal process> In the oxygen removal process, oxygen is removed from the trace gas components discharged from the trap pipe 9.

[0062] Specifically, oxygen is adsorbed and trapped from trace gas components introduced into the oxygen trap 12 by carrier gas CG through the flow path F6 and removed.

[0063] Here, regarding the separation of oxygen and argon by the oxygen trap 12, by passing trace gas components through the oxygen trap 12, oxygen is adsorbed and removed, and only argon is detected. The oxygen trap 12 is a commercially available product, and its effectiveness deteriorates by adsorbing large amounts of oxygen. However, while its oxygen adsorption capacity is on the order of liters, the amount of oxygen in the trace gas components targeted by this invention is at the ppm level, so aging and regeneration of the oxygen trap 12 is hardly necessary.

[0064] <Gas component separation process> In the gas component separation process, the trace gas components from which oxygen has been removed are separated into multiple types of gas components excluding the oxygen component by the main column.

[0065] Specifically, the trace gaseous components from which oxygen has been removed are separated into argon, nitrogen, and other gaseous components in the main column section 4a.

[0066] Under typical conditions, the gas component introduced into the main column section 4a is separated into argon + oxygen and nitrogen, and argon and oxygen are not separated and are detected as a single peak. In contrast, in the present invention, by providing an oxygen trap 12 before the main column section 4a, oxygen is adsorbed and collected by the oxygen trap 12, and as a result, argon is detected as a single peak.

[0067] <Detection Process> In the detection process, multiple types of gaseous components from which oxygen has been removed in the preceding stage are detected.

[0068] Specifically, a detector 13, consisting of a thermal conductivity detector and the like, detects multiple types of gas components. The gas subjected to this detection is then discharged outside the concentration measuring device 1.

[0069] The detection results are output by the PC 15 of the data processing device 14 as thick arrows and displayed on a display unit (not shown) or printed.

[0070] The above measurement method is performed automatically by PC15 and control unit16. Alternatively, it may be performed manually.

[0071] Thus, according to the measurement method of this embodiment, human intervention is avoided, and measures are taken to collect the water to be measured as the sample water, to increase sensitivity through concentration, and to prevent column degradation due to a large amount of sample water, enabling high-precision measurement of trace gaseous components present in water such as ultrapure water.

[0072] Next, we will describe the embodiment shown in Figure 2.

[0073] Figure 2 shows the overall configuration of another embodiment of the water trace gas component concentration measuring device of the present invention.

[0074] This embodiment is a modification of the introduction unit 2, which is used as an introduction means for introducing the water to be measured into the measuring device 3, compared to the embodiment shown in Figure 1. Since there are no other changes to the other components, they are denoted by the same reference numerals.

[0075] In this embodiment, a flexible container 25 (for example, a medical infusion bag) is used instead of the metal sample cylinder 5 of the previous embodiment. Only the water to be measured is collected in this flexible container 25, while preventing air components from entering. 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 installed by housing it inside the pressurized case 26. Stop valves ST1 and ST2 are attached to the upstream and downstream flow paths F1 of the flexible container 25, respectively.

[0076] Next, the measurement method according to this embodiment will be described.

[0077] <Introduction process> In the introduction process, a predetermined amount of the water to be measured, which is present due to the mixing of trace gaseous components, is introduced into the measuring device 3, which serves as the measuring means.

[0078] Specifically, first, the water to be measured is sealed inside a flexible container 25 with an internal volume of approximately 1 liter, ensuring that no air components enter, and then connected to the flow path F1 of the introduction unit 2.

[0079] Subsequently, the stop valves ST1 and ST2 are carefully opened, and the flexible container 25 is pressed from the outside with a slight pressure using purge gas PG2 (any type of purge gas is acceptable, but He is recommended to prevent contamination), pushing the water to be measured downstream of the flow path F1, and then introducing it into the measuring tube 6 through the flow path F2.

[0080] In addition to the above, the flexible container 25 may be placed above the measuring device 3 and adjusted so that the water to be measured flows through the downstream channels F1 and F2 by its own weight and into the measuring pipe 6.

[0081] From the <gas-water separation process> to the <detection process> Since the process from the <gas-water separation step> to the <detection step> in the above embodiment is carried out in exactly the same manner, the explanation will be omitted.

[0082] Furthermore, this embodiment can achieve the same effects as the previous embodiment, so a further explanation will be omitted.

[0083] <Examples> Next, an example of concentration measurement using the concentration measurement device 1 for trace gas components in water according to the present invention, shown in Figure 1 or Figure 2, will be described. Since the procedure is performed identically in both figures, the following description will focus on the example of concentration measurement using the concentration measurement device 1 for trace gas components in water shown in Figure 1.

[0084] <Measurement of standard gases> Before measuring the water sample, the above-described steps from the <introduction step> to the <detection step> were performed using a standard gas containing predetermined amounts of argon and helium.

[0085] Specifically, standard gas Ar1000ppm / He was connected to flow path F2, loaded into measuring tube 6 of switching valve V1, and then the measurement was performed by sequentially executing all steps from the <introduction process> to the <detection process>. Note that at 20°C and 1 atm, 0.3324 μg of standard gas Ar1000ppm / He is loaded into 200 μL of measuring tube.

[0086] The chromatographic data obtained by the detector 13 is processed by the PC (personal computer) 15 of the data processing device 14 and displayed on a display device (not shown) or printed out as chromatographic data for the standard gas shown in Figure 3. As shown in Figure 3, 0.3324 μg of argon was measured at a height of 2518 μV at a retention time of 6.062 minutes. The peak position of oxygen appears superimposed on the peak position of argon, but since the standard gas does not contain oxygen, the reliability of the argon measurement result shown in Figure 3 is extremely high. Furthermore, even if the standard gas contained oxygen, in this embodiment, oxygen is reliably removed in the <oxygen removal process>, so the oxygen peak is not measured, and the reliability of the argon measurement result is maintained at a high level. This argon measurement result was used as the measurement standard for argon in the water to be measured thereafter.

[0087] <Measurement of water sample 1> As the water to be measured (Water 1), a liquid containing trace amounts of argon that had not undergone degassing treatment in ultrapure water was prepared, and the above-mentioned <introduction step> to <detection step> was performed.

[0088] Specifically, a sample of water to be measured (1) was prepared and supplied to a metal sample cylinder (5). Then, the measurement was performed by sequentially executing all steps from the <introduction step> to the <detection step>.

[0089] The chromatographic data obtained by the detector 13 is processed by the PC (personal computer) 15 of the data processing device 14 and displayed on a display device (not shown) or printed out as chromatographic data of trace gases present in the water sample 1, as shown in Figure 4. As shown in Figure 4, argon was detected as a peak with a height of 360 μV at a retention time of 5.897 minutes, and its concentration was measured as 0.0407 μg (equivalent to 203.5000 ppb in water). The retention time of the argon peak in the water sample 1, 5.897 minutes, matches the retention time of the argon peak of the standard gas, 6.062 minutes, indicating high reliability of the argon measurement result shown in Figure 4. Moreover, the argon content was reliably measured despite being on the order of trace amounts in ppb. Furthermore, in this embodiment, oxygen present in the water sample 1 is reliably removed in the <oxygen removal process>, so no oxygen peak is measured, and the reliability of the argon measurement result is maintained. In Figure 4, the peak to the right of Alcon represents nitrogen gas.

[0090] <Measurement of water sample 2> As the water to be measured 2, a liquid containing a small amount of argon after degassing treatment was prepared in ultrapure water, and the above-mentioned <introduction step> to <detection step> was performed.

[0091] Specifically, the water sample 2 to be measured was prepared and supplied to the metal sample cylinder 5, and then the measurement was performed by sequentially executing all steps from the <introduction step> to the <detection step>.

[0092] The chromatographic data obtained by the detector 13 is processed by the PC (personal computer) 15 of the data processing device 14 and displayed on a display device (not shown) or printed out as chromatographic data of trace gases present in the water sample 2, as shown in Figure 5. As shown in Figure 5, a peak with a height of 44 μV was detected for argon at a retention time of 5.925 minutes, and its concentration was measured as 0.0047 μg (equivalent to 23.5000 ppb in water). The retention time of the argon peak in the water sample 2, 5.925 minutes, matches the retention time of the argon peak of the standard gas, 6.062 minutes, indicating high reliability of the argon measurement result shown in Figure 5. Moreover, the argon content was reliably measured despite being on the order of trace amounts in ppb. Furthermore, in this embodiment, oxygen present in the water sample 2 is reliably removed in the <oxygen removal process>, so no oxygen peak is measured, and the reliability of the argon measurement result is maintained. In Figure 5, the peak to the right of Alcon represents nitrogen gas.

[0093] As shown in the measurement results of each embodiment in Figures 4 and 5, the water trace gas component concentration measuring device 1 of the present invention can reliably and accurately measure argon, a trace gas (content on the order of ppb) contained in the sample waters 1 and 2, without being affected by oxygen, and the reliability is also very high.

[0094] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible. For example, in the introduction means, instead of using a metal sampling cylinder 5 or a flexible container 25, the system may be configured to supply the water to be measured to the flow path F2 of the measuring device 3 online through the flow path F1. [Explanation of Symbols]

[0095] 1. Concentration and measurement device for trace gaseous components in water. 2. Installation Unit 3. Measuring device 4. Gas chromatograph 4a Main column 5. Metal sample cylinder 6 Metering tube 7 Pre-column 8. Gas-water separation unit 9 Trap pipe 10 Heaters 11 Duabin 12. Oxygen trap 13 detectors 14 Data Processing Devices 15 PC (personal computer) 25 Flexible containers V1~V4 Switching valve F1~F6 channel ST1~ST4 Stop Valve

Claims

1. A method for measuring the concentration of trace gas components in water, which involves measuring the concentration of argon as a trace gas component present in ultrapure water using a gas chromatograph, An introduction step of introducing a predetermined amount of the ultrapure water, which is the water to be measured in which the trace gas component is present, into the measuring means, A gas-water separation step is performed in which the water to be measured, introduced into the measuring means, is separated into trace gas components and water by a pre-column. A concentration step of cooling and concentrating the trace gaseous component separated from the water, A dispensing step in which the concentrated trace gaseous component is heated and sent to the main column section, An oxygen removal step is performed to remove oxygen from the trace gas component that has been delivered, A gas component separation step in which the trace gas component from which oxygen has been removed is separated by the main column portion into one or more types of gas components excluding the oxygen component, A detection step for detecting one or more types of separated gas components, A concentration measurement method characterized by measuring the concentration of argon as a trace gas component present in ultrapure water by proceeding through the steps in order.

2. A concentration measurement method according to claim 1, characterized in that the oxygen removal step is a step of removing oxygen using an oxygen removal agent.

3. A concentration measurement method according to claim 1 or 2, characterized in that the concentration of argon in ultrapure water is 1 ppm or less.

4. A device for measuring the concentration of trace gas components in water, which measures the concentration of argon as a trace gas component present in ultrapure water using a gas chromatograph, An introduction means for introducing a predetermined amount of the ultrapure water to be measured into the flow path of the measuring means, A gas-water separation means for separating the water to be measured, introduced into the flow path of the measuring means, into trace gas components and water using a pre-column, A concentration means for cooling and concentrating the trace gaseous component separated from the water, and then heating the concentrated trace gaseous component and sending it to the main column section, An oxygen removal means for removing oxygen from the trace gas component that is delivered, A gas component separation means that separates the trace gas component from which oxygen has been removed into one or more types of gas components excluding the oxygen component by the main column portion, A detection means for detecting one or more types of separated gas components A device for measuring the concentration of trace gas components in water, characterized by having a function to measure the concentration of argon as a trace gas component present in ultrapure water.

5. The introduction means is a metal sample cylinder or flexible container capable of being filled with a predetermined amount of the water to be measured, and is configured to introduce the water to be measured into the flow path while connected to the flow path and separated from the outside air. The gas-water separation means is configured such that the separated water is discharged outside the measuring means by causing the purge gas to flow back through the pre-column, as described in claim 4, for concentration and measurement of trace gas components in water.

6. The water flow path is configured to transport the water to be measured, the separated trace gas components, water, and concentrated trace gas components by an operating gas supplied into the flow path from outside the measuring means and a switching valve installed in the middle of the flow path, as described in claim 4 or 5.

7. The apparatus for measuring the concentration of trace gas components in water according to any one of claims 4 to 6, characterized in that the concentration of argon in ultrapure water measured by the detection means is 1 ppm or less.

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