JP2017190999A - Total organic carbon measurement device and carbon dioxide extraction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a total organic carbon measurement device with which it is possible to improve measurement accuracy, and provide a carbon oxide extraction method with which it is possible to improve measurement accuracy in the total organic carbon measurement device.SOLUTION: A pH control unit 112 adds an alkali solution to the internal liquid of a liquid reservoir unit to make the internal liquid of the liquid reservoir alkaline. In this state, a sample having had inorganic carbon removed is supplied to the inside of the combustion tube of a reaction unit 4. Inside the combustion tube, carbon dioxide corresponding to the amount of total carbon included in the sample is generated. This carbon dioxide is supplied to the liquid reservoir unit and dissolved in the internal liquid of the liquid reservoir unit. Thereafter, the pH control unit 112 adds an acid solution to the internal liquid to make the internal liquid of the liquid reservoir unit acidic. Then, carbon dioxide dissolved in the internal liquid of the liquid reservoir unit is extracted at a time. For this reason, carbon dioxide generated over a long time in the reaction unit 4 can be dissolved in the internal liquid of the liquid reservoir unit and retained therein, and can thereafter be extracted at a time.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a total organic carbon measuring device for measuring total organic carbon contained in a sample, and a carbon dioxide extraction method using the total organic carbon measuring device.

  Conventionally, total organic carbon measuring devices for measuring total organic carbon contained in various samples in addition to environmental water such as river water, lake water, marine water, rain water, and groundwater have been used.

  As a total organic carbon measuring device, a removal processing unit that removes inorganic carbon contained in the sample, a reaction unit (carbon combustion unit) that generates carbon dioxide from all carbon contained in the sample, and detection of the generated carbon dioxide An apparatus including a detection unit (measurement unit) is known (for example, see Patent Document 1 below).

  In such a total organic carbon measuring device, the sample is first sent to the removal processing unit. Then, in the removal processing unit, the inorganic carbon is removed from the sample by adding acid to the sample and bubbling. The sample after the inorganic carbon is removed is sent to the reaction section. Then, carbon dioxide is generated by heating the sample in the reaction section. The detection unit detects the generated carbon dioxide. Based on the amount of carbon dioxide detected by the detector, the amount of total organic carbon contained in the sample is calculated.

Japanese Patent No. 2671773

  In the conventional all-organic carbon measuring apparatus as described above, the calculation accuracy (measurement accuracy) of all-organic carbon may be lowered. Specifically, in the reaction unit, it usually takes a certain time or longer to react the sample. And a detection part detects the carbon dioxide which generate | occur | produced in the meantime over a long time, and the integrated value is measured as a generation amount of a carbon dioxide. Therefore, there is a limit in improving detection sensitivity, and there is a limit in improving measurement accuracy of all organic carbon.

  This invention is made | formed in view of the said situation, and it aims at providing the total organic carbon measuring apparatus which can improve a measurement precision. Moreover, an object of this invention is to provide the carbon dioxide extraction method which can improve the measurement precision in a total organic carbon measuring apparatus.

(1) The total organic carbon measuring device according to the present invention measures total organic carbon contained in a sample. The total organic carbon measuring device includes a reaction unit, a detection unit, a liquid storage unit, and a pH adjustment unit. The reaction unit generates carbon dioxide from inorganic carbon or total carbon contained in the sample. The detection unit detects carbon dioxide generated in the reaction unit. The liquid storage unit is provided between the reaction unit and the detection unit, and stores an internal liquid that can contact carbon dioxide generated in the reaction unit. The pH adjusting unit adjusts the pH of the internal liquid stored in the liquid storing unit. When the carbon dioxide is introduced into the liquid storage part from the reaction part, the pH adjusting part makes the internal liquid stored in the liquid storage part alkaline, thereby generating carbon dioxide in the internal liquid. The carbon dioxide in the internal liquid is extracted by dissolving and then acidifying the internal liquid.

  According to such a configuration, when carbon dioxide is introduced from the reaction unit into the liquid storage unit in a state where the internal liquid stored in the liquid storage unit has been made alkaline by the pH adjusting unit, the inside of the liquid storage unit Carbon dioxide is dissolved in the liquid. After that, when the internal liquid stored in the liquid storage unit is acidified by the pH adjusting unit, carbon dioxide dissolved in the internal liquid of the liquid storage unit is extracted. Further, the detection unit detects carbon dioxide generated in the reaction unit by detecting carbon dioxide extracted from the liquid storage unit.

Therefore, by making the internal liquid of the liquid storage part alkaline by the pH adjusting part, carbon dioxide generated over a long period of time in the reaction part can be dissolved and retained in the internal liquid of the liquid storage part. And the carbon dioxide which is melt | dissolving in the internal liquid of a liquid storage part can be extracted at once by making the internal liquid of a liquid storage part acidic by a pH adjustment part. Moreover, the carbon dioxide extracted at once can be detected in the detection unit.
As a result, the detection time in the detection unit can be shortened, and the detection sensitivity can be improved.
Therefore, the measurement accuracy in the total organic carbon measuring device can be improved.

(2) Moreover, the said liquid storage part may bubble the carbon dioxide which generate | occur | produced in the said reaction part in the said internal liquid.

  According to such a configuration, carbon dioxide generated in the reaction unit can be efficiently dissolved in the internal liquid of the liquid storage unit.

(3) Moreover, even if the said liquid storage part is comprised with the IC reactor which stores an acid solution as said internal liquid, and generates carbon dioxide by making the inorganic carbon contained in a sample react with an acid solution. Good.

According to such a structure, a liquid storage part can be comprised using the existing member in a total organic carbon measuring apparatus.
Therefore, it is possible to suppress an increase in the number of parts in the total organic carbon measuring device.

(4) The all-organic carbon measuring device may further include a reaction control unit. The reaction control unit generates carbon dioxide a plurality of times in the reaction unit in a state in which the internal liquid stored in the liquid storage unit is made alkaline by the pH adjusting unit. The pH adjusting unit is configured to acidify the internal liquid after carbon dioxide generated a plurality of times by the reaction control unit is introduced into the liquid storage unit and dissolved in the internal liquid stored in the liquid storage unit. By doing so, carbon dioxide in the internal liquid may be extracted.

  Generally, in the total organic carbon measurement device, the more sample that is sent to the reaction unit, the more carbon dioxide that the detection unit detects, and as a result, the measurement accuracy of total organic carbon improves. To do. On the other hand, the size and shape of the reaction part may be limited for structural reasons. In this case, the amount of sample that can be sent to the reaction unit is limited, and the amount of carbon dioxide detected by the detection unit is also limited.

According to the configuration described above, carbon dioxide is generated a plurality of times from the reaction unit in a state where the internal liquid of the liquid storage unit is made alkaline by the pH adjustment unit by the control of the reaction control unit. The carbon dioxide generated multiple times is dissolved in the internal liquid of the liquid reservoir and remains in the liquid reservoir. And if the internal liquid of a liquid storage part is acidified by the pH adjustment part, the carbon dioxide which melt | dissolves in the internal liquid of a liquid storage part will be extracted at once.
Therefore, the amount of carbon dioxide detected by the detection unit can be increased.
As a result, the detection sensitivity in the detection unit can be improved.

(5) Moreover, the said liquid storage part may store the said internal liquid within a fixed quantity, and may discharge | emit the internal liquid exceeding the said fixed quantity to a drain flow path.

  According to such a configuration, the amount of the internal liquid in the liquid storage unit can be kept constant. For example, when the pH adjustment unit adjusts the pH of the internal solution by adding an acid solution and an alkali solution to the internal solution of the liquid storage unit, the internal solution increases by adding the acid solution and the alkali solution. However, the internal liquid exceeding a certain amount can be discharged to the outside from the drain channel. And the quantity of internal liquid can be kept constant.

(6) The carbon dioxide extraction method according to the present invention includes a reaction unit that generates carbon dioxide from inorganic carbon or total carbon contained in a sample, and a detection unit that detects carbon dioxide generated in the reaction unit, A total organic carbon measuring device for measuring total organic carbon contained in a sample based on a detection result in the detection unit is used. The carbon dioxide extraction method includes a liquid storage step and a pH adjustment step. In the liquid storage step, an internal liquid that can contact carbon dioxide generated in the reaction unit is stored in a liquid storage unit provided between the reaction unit and the detection unit. In the pH adjustment step, the pH of the internal liquid stored in the liquid storage unit is adjusted. In the pH adjustment step, when carbon dioxide is introduced from the reaction unit into the liquid storage unit, the internal liquid stored in the liquid storage unit is made alkaline, so that carbon dioxide is contained in the internal liquid. The carbon dioxide in the internal liquid is extracted by dissolving and then acidifying the internal liquid.

(7) In the carbon dioxide extraction method, the liquid storage unit may bubble carbon dioxide generated in the reaction unit in the internal liquid.

(8) In the carbon dioxide extraction method, an IC reaction in which the liquid storage unit stores an acid solution as the internal liquid and generates carbon dioxide by reacting inorganic carbon contained in the sample with the acid solution. You may be comprised by the vessel.

(9) The carbon dioxide extraction method may further include a reaction control step. In the reaction control step, carbon dioxide is generated a plurality of times in the reaction unit in a state in which the internal liquid stored in the liquid storage unit is made alkaline by the pH adjustment step. In the pH adjustment step, carbon dioxide generated a plurality of times in the reaction control step is introduced into the liquid storage part and dissolved in the internal liquid stored in the liquid storage part, and then the internal liquid is acidified. By doing so, carbon dioxide in the internal liquid may be extracted.

(10) In the carbon dioxide extraction method, the liquid storage unit may store the internal liquid within a certain amount and discharge the internal liquid exceeding the certain amount to the drain flow path.

  According to the present invention, by making the internal liquid of the liquid storage unit alkaline by the pH adjusting unit, carbon dioxide generated over a long period of time in the reaction unit can be dissolved and retained in the internal liquid of the liquid storage unit. it can. And the carbon dioxide which is melt | dissolving in the internal liquid of a liquid storage part can be extracted at once by making the internal liquid of a liquid storage part acidic by a pH adjustment part. Therefore, the detection time in the detection unit can be shortened, and the detection sensitivity can be improved. As a result, the measurement accuracy in the total organic carbon measuring device can be improved.

It is the schematic which showed the all-organic carbon measuring apparatus which concerns on one Embodiment of this invention. It is the block diagram which showed the specific structure of the control part of the all-organic carbon measuring apparatus of FIG. 1, and its peripheral member. It is the flowchart which showed an example of the process by a control part.

1. Overall Configuration of Total Organic Carbon Measuring Device FIG. 1 is a schematic diagram showing a total organic carbon measuring device 1 according to an embodiment of the present invention.
The total organic carbon measuring device 1 is based on inorganic carbon (IC: Inorganic Carbon) and total carbon (TC: Total Carbon) contained in a sample, and is based on total organic carbon (TOC) contained in the sample. , A supply unit 2, an injection unit 3, a reaction unit 4, a liquid storage unit 5, a dehumidifier 6, and a detection unit 7.

The supply unit 2 is for supplying samples, solutions, and the like (additives) used in the total organic carbon measurement device 1, and includes a sample supply unit 21, an acid solution supply unit 22, and an alkaline solution supply unit 23. And a pure water supply unit 24.
The sample supply unit 21 stores a liquid sample to be measured.
The acid solution supply unit 22 stores an acid solution used for measurement. The acid solution stored is, for example, HCl.

The alkaline solution supply unit 23 stores an alkaline solution used for measurement. The alkaline solution stored is, for example, NaOH.
The pure water supply unit 24 stores pure water. The pure water is used as an internal liquid (described later) of the liquid storage unit 5 and cleaning water for each member. However, the internal liquid is not limited to pure water but may be an organic solvent or the like.

  The injection unit 3 is for selectively collecting and sending each additive in the supply unit 2, and includes a syringe body 31, a plunger 32, and a distribution valve 33.

  The syringe body 31 is formed in a cylindrical shape. The syringe body 31 is formed with a vent hole (not shown) through which the carrier gas flows from the first gas supply pipe 8 into the inside.

  The plunger 32 is formed in a rod shape. One end of the plunger 32 is inserted into the syringe body 31. The plunger 32 slides along the axial direction of the syringe main body 31 when a driving force from a motor (not shown) is applied.

The distribution valve 33 is a multi-port distribution valve having one common port and a plurality of distribution ports. In FIG. 1, each port of the distribution valve 33 is omitted and not shown. The distribution valve 33 is selectively connected between the common port and one of the distribution ports by applying a driving force from a motor (not shown). The tip of the syringe body 31 is connected to the common port of the distribution valve 33. In each distribution port of the distribution valve 33, a sample suction channel 9 that is continuous in the sample supply unit 21, an acid solution suction channel 10 that is continuous in the acid solution supply unit 22, and an alkali that is continuous in the alkali solution supply unit 23 are provided. A solution suction channel 11, a washing water suction channel 12 continuous in the pure water supply unit 24, a sample transfer channel 13 connected to the reaction unit 4, a conditioning liquid transfer channel 14 connected to the liquid storage unit 5, And the 1st drain flow path 15 is connected.
The reaction unit 4 includes an electric furnace 41 and a combustion tube 42.
The electric furnace 41 is for heating the sample to be measured, and is formed in a hollow shape.

  The combustion tube 42 is disposed in the electric furnace 41. The combustion tube 42 is made of, for example, hard glass (quartz glass). The combustion pipe 42 is filled with an oxidation catalyst (not shown). When the sample is injected into the combustion tube 42, the organic matter contained in the sample is oxidized by the action of the oxidation catalyst to generate carbon dioxide corresponding to the amount of the organic matter (total carbon) contained in the sample. The combustion pipe 42 is connected to the sample transfer flow path 13 and the second gas supply pipe 16 at one end thereof, and is connected to the third gas supply pipe 17 at the other end thereof. Carrier gas flows from the second gas supply pipe 16 into the combustion pipe 42.

  The liquid storage part 5 is formed in a long hollow shape, and is configured to store a liquid therein. The adjustment liquid transfer channel 14 described above is connected to one end (upper end) of the liquid reservoir 5, and the third gas supply pipe 17 is connected to the other end (lower end) of the liquid reservoir 5. Has been. In addition, an internal liquid supply channel 18 and a second drain channel 19 are connected to the liquid reservoir 5. The liquid storage unit 5 is provided between the reaction unit 4 and a detection unit 7 described later.

  One end of the internal liquid supply channel 18 is continuous in the pure water supply unit 24, and the other end is connected to the liquid storage unit 5. A pump 100 is interposed in the internal liquid supply channel 18.

  The second drain channel 19 is connected to the central part of the liquid reservoir 5. The liquid (internal liquid) in the liquid storage unit 5 is discharged to the outside from the second drain channel 19 when the amount exceeds a certain amount. A valve 101 is interposed in the second drain channel 19. When the valve 101 is opened, the second drain channel 19 discharges the internal liquid that has reached a certain amount or more in the liquid storage unit 5, and the liquid storage unit 5 is closed by closing the valve 101. The gas passing through the inside is guided to the discharge pipe 102 side.

The dehumidifier 6 is for removing moisture contained in the gas discharged from the liquid storage unit 5, and is disposed in the middle of the discharge pipe 102 that connects the liquid storage unit 5 and the detection unit 7 described later. Has been placed.
The detection unit 7 is for detecting carbon dioxide contained in the gas discharged through the discharge pipe 102. The detection part 7 is comprised by the infrared carbon dioxide detector, for example.

  In the total organic carbon measuring device 1, the common port and the selected distribution port are appropriately connected in the distribution valve 33 of the injection unit 3. And the plunger 32 of the injection | pouring part 3 slides in the syringe main body 31, and an additive etc. are extract | collected (aspiration) from the supply part 2, and the extract | collected additive etc. are sent out.

  Specifically, in the total organic carbon measurement device 1, a sample is collected from the sample supply unit 21 into the syringe body 31 of the injection unit 3 through the sample suction channel 9. An acid solution is collected in the syringe body 31 from the acid solution supply unit 22 via the acid solution suction channel 10. Then, the carrier gas is supplied from the first gas supply pipe 8 into the syringe body 31 and bubbled, whereby the inorganic carbon contained in the sample is removed.

  In the all organic carbon measuring device 1, the carrier gas is always supplied to the second gas supply pipe 16. Therefore, in the total organic carbon measurement device 1, the carrier that sequentially passes through the second gas supply pipe 16, the reaction unit 4, the third gas supply pipe 17, the liquid storage unit 5, and the discharge pipe 102 toward the detection unit 7. A gas flow is formed.

  The sample from which the inorganic carbon has been removed in the injection unit 3 is supplied from the injection unit 3 into the combustion tube 42 of the reaction unit 4 via the sample transfer channel 13. When the combustion tube 42 is heated by the electric furnace 41, carbon dioxide corresponding to the amount of organic matter (total carbon) contained in the sample is generated in the combustion tube 42. Carbon dioxide generated in the combustion pipe 42 is supplied to the liquid storage unit 5 through the third gas supply pipe 17.

  The carbon dioxide supplied to the liquid reservoir 5 is discharged from the liquid reservoir 5 by performing predetermined control (described later). The carbon dioxide discharged from the liquid storage unit 5 is dehydrated by the dehumidifier 6 in the process of passing through the discharge pipe 102, and then flows into the detection unit 7. The detection unit 7 detects the amount of carbon dioxide exhausted from the exhaust pipe 102. Then, based on the amount of carbon dioxide detected by the detection unit 7, the total organic carbon (TOC concentration) contained in the sample is measured.

  Thus, in the total organic carbon measurement device 1, after the inorganic carbon contained in the sample is removed, the total carbon contained in the sample is determined based on the amount of carbon dioxide generated by oxidation of the sample. Airframe carbon is measured.

Such a method for measuring total organic carbon is based on the relational expression of TOC = TC-IC. That is, when inorganic carbon (IC) contained in a sample is removed, a relational expression of TOC = TC can be applied to subsequent samples. Therefore, total organic carbon (TOC) contained in the sample is measured by measuring total carbon (TC) based on carbon dioxide generated from the sample after removing inorganic carbon (IC). . Details of this measurement method will be described later.
In addition, the total organic carbon measuring device 1 can measure total organic carbon by other methods in addition to the above-described method.

  Specifically, when other methods are used, in the total organic carbon measurement device 1, first, the liquid storage unit is operated from the pure water supply unit 24 through the internal liquid supply channel 18 by the operation of the pump 100. 5 is supplied with pure water, and the acid solution is collected from the acid solution supply unit 22 into the syringe body 31 of the injection unit 3 through the acid solution suction channel 10. The collected acid solution is added (dropped) from the injection unit 3 (syringe body 31) to the liquid storage unit 5 through the adjustment liquid transfer channel 14. Thereby, a certain amount of acidic solution (pure water and acid solution) is stored in the liquid storage part 5 as an internal liquid.

  Further, a sample is collected from the sample supply unit 21 into the syringe body 31 of the injection unit 3 through the sample suction channel 9. The sample is added (dropped) from the injection unit 3 to the liquid storage unit 5 through the adjustment liquid transfer channel 14.

  The internal liquid (internal liquid containing the sample and the acidic solution) in the liquid storage unit 5 is bubbled by the carrier gas supplied from the third gas supply pipe 17. Thereby, the inorganic carbon contained in the sample reacts with the acid solution (acid solution) to generate carbon dioxide. The generated carbon dioxide is dehydrated by the dehumidifier 6 in the process of passing through the discharge pipe 102, and then flows into the detection unit 7. The detection unit 7 detects the amount of carbon dioxide exhausted from the exhaust pipe 102. Then, based on the amount of carbon dioxide detected by the detection unit 7, inorganic carbon (IC concentration) contained in the sample is measured.

  In addition, the sample is collected from the sample supply unit 21 into the syringe body 31 of the injection unit 3 through the sample suction channel 9 while the internal liquid in the liquid storage unit 5 is acidic. The collected sample is supplied from the injection unit 3 through the sample transfer channel 13 into the combustion tube 42 of the reaction unit 4. When the combustion tube 42 is heated by the electric furnace 41, carbon dioxide corresponding to the amount of organic matter (total carbon) contained in the sample is generated in the combustion tube 42. Carbon dioxide generated in the combustion pipe 42 passes through the third gas supply pipe 17, the liquid storage section 5 and the discharge pipe 102 and flows into the detection section 7. The detection unit 7 detects the amount of carbon dioxide exhausted from the exhaust pipe 102. And based on the quantity of the carbon dioxide which the detection part 7 detected, the total carbon (TC density | concentration) contained in a sample is measured.

And (TOC density | concentration) is measured by applying the relational expression of TOC = TC-IC. When this method is used, the liquid storage unit 5 functions as an IC reactor. That is, the liquid storage part 5 is comprised by the IC reactor which generate | occur | produces a carbon dioxide by making the inorganic carbon contained in a sample react with an acid solution.
Thus, the total organic carbon measuring apparatus 1 can measure the total organic carbon contained in the sample by two measurement methods.

  Here, in the total organic carbon measuring device 1, it takes a certain time (long time) in order to react the sample in the reaction unit 4. Further, the detection unit 7 measures the detected integrated value as the amount of carbon dioxide generated. Therefore, if the detection unit 7 detects carbon dioxide during the reaction of the sample in the reaction unit 4, detection is performed for a long time. As a result, it becomes difficult to improve detection sensitivity. Therefore, in the present embodiment, carbon dioxide from the reaction unit 4 is sent to the detection unit 7 using the following configuration and method.

2. FIG. 2 is a block diagram showing a specific configuration of the control unit 110 of the total organic carbon measuring device 1 and its peripheral members.

  The total organic carbon measuring device 1 includes an operation unit 105, a display unit 106, a carrier gas delivery unit 107, and a control unit 110 in addition to the injection unit 3, the reaction unit 4, and the detection unit 7 described above.

The operation unit 105 is configured by, for example, a keyboard and a mouse. The user can input various information such as measurement conditions to the control unit 110 by operating the operation unit 105.
The display unit 106 is configured by, for example, a liquid crystal display. Various types of information such as measurement results are displayed on the display unit 12 under the control of the control unit 110.

  The carrier gas delivery unit 107 supplies a carrier gas to the first gas supply pipe 8 and the second gas supply pipe 16 (see FIG. 1). The carrier gas delivery unit 107 constantly supplies a carrier gas to the second gas supply pipe 16, while supplying a carrier gas to the first gas supply pipe 8 as necessary.

  For example, the control unit 110 includes a CPU (Central Processing Unit). The control unit 110 can input or output electrical signals between the injection unit 3, the reaction unit 4, the detection unit 7, the pump 100, the operation unit 105, the display unit 106, and the carrier gas delivery unit 107. The control unit 110 functions as a reaction control unit 111, a pH control unit 112, a calculation processing unit 113, a display processing unit 114, and the like when the CPU executes a program.

The reaction control unit 111 performs processing for controlling operations of the injection unit 3, the reaction unit 4, the pump 100, and the carrier gas delivery unit 107.
The pH control unit 112 performs a process for controlling the operation of the injection unit 3. The pH control unit 112 and the injection unit 3 constitute a pH adjustment unit.
The calculation processing unit 113 calculates the concentrations of inorganic carbon, total carbon, and total organic carbon based on the detection signal from the detection unit 7.
The display processing unit 114 performs processing for causing the display unit 106 to display the result calculated by the calculation processing unit 113.

3. Control Operation by Control Unit FIG. 3 is a flowchart showing an example of processing by the control unit 110.
As described above, when the total organic carbon contained in the sample is measured after removing the inorganic carbon contained in the sample in the total organic carbon measuring device 1, the user first operates the operation unit 105. Operate and input measurement conditions and then start measurement.

  Although not described here, the liquid in the injection unit 3 is appropriately cleaned by collecting pure water in the pure water supply unit 24, and the liquid that is no longer necessary in the injection unit 3 is the first drain channel. 15 is appropriately discharged.

First, the reaction control unit 111 operates the pump 100 to supply pure water into the liquid storage unit 5 from the pure water supply unit 24 via the internal liquid supply channel 18. And a fixed amount of pure water is stored as an internal liquid in the liquid storage part 5 (liquid storage step).
In this example, about 10 ml of pure water is stored in the liquid storage unit 5 as an internal liquid.

Further, the pH control unit 112 operates the injection unit 3 to collect the alkaline solution from the alkaline solution supply unit 23 through the alkaline solution suction channel 11 into the syringe body 31. Furthermore, the pH controller 112 adds (drops) the alkaline solution collected in the syringe body 31 to the internal liquid of the liquid reservoir 5 via the adjustment liquid transfer channel 14 by operating the injection unit 3. (Step S101). Thereby, the internal liquid of the liquid storage part 5 becomes alkaline.
In this example, 0.1 ml of NaOH (1N) is added to the internal liquid of the liquid reservoir 5. As a result, the pH of the internal liquid in the liquid reservoir 5 becomes approximately 12.

Then, the reaction control unit 111 operates the injection unit 3 to collect a sample from the sample supply unit 21 through the sample suction channel 9 into the syringe body 31 of the injection unit 3. The reaction control unit 111 operates the injection unit 3 to collect the acid solution from the acid solution supply unit 22 through the acid solution suction channel 10 into the syringe body 31 of the injection unit 3 (step S102). .
In this example, 3 ml of a sample is collected in the syringe body 31 of the injection unit 3 and 45 μl of HCl (1N) is collected.

  And the reaction control part 111 operates the carrier gas delivery part 107, and supplies carrier gas in the syringe main body 31 from the 1st gas supply pipe 8 (step S103). Thereby, the sample and acid solution in syringe main body 31 are bubbled, and the inorganic carbon contained in the sample is removed. The reaction control unit 111 constantly supplies the carrier gas to the second gas supply pipe 16 by operating the carrier gas delivery unit 107.

Then, when a predetermined time (in this example, 90 seconds) elapses (YES in step S104), the reaction control unit 111 stops the supply of the carrier gas into the syringe body 31. The reaction control unit 111 operates the injection unit 3 so that the sample of the syringe main body 31 (the sample after the inorganic carbon is removed) passes through the sample transfer channel 13 and the combustion tube of the reaction unit 4. (Step S105).
In this example, 2000 μl, which is a part of the sample in the syringe body 31, is supplied into the combustion tube 42 of the reaction unit 4.
In the reaction unit 4, the temperature in the electric furnace 41 is adjusted to a predetermined temperature (in this example, 680 ° C.) by the reaction control unit 111.

  Thereby, the combustion tube 42 is heated by the electric furnace 41, and carbon dioxide corresponding to the amount of organic matter (total carbon) contained in the sample is generated in the combustion tube 42. Carbon dioxide generated in the combustion pipe 42 is supplied to the liquid storage unit 5 through the third gas supply pipe 17 by the flow of the carrier gas.

The carbon dioxide supplied to the liquid reservoir 5 flows into the internal liquid in the liquid reservoir 5 from below. Thereby, the carbon dioxide from the reaction part 4 bubbles the internal liquid in the liquid storage part 5. In this way, carbon dioxide from the reaction unit 4 is dissolved in the internal liquid by contacting the internal liquid in the liquid storage unit 5.
This is due to the fact that the internal liquid in the liquid storage unit 5 is alkaline, and specifically, due to the following formula (1).

Formula (1) has shown the presence form of the carbon dioxide in water. Specifically, the equation (1) indicates that when the pH of water increases, the equilibrium moves to the right and carbon dioxide exists as ions, and when the pH of water decreases, the equilibrium moves to the left and all of the carbon dioxide is It shows that it exists as dissolved carbon dioxide (dissolved CO ₂ ). More specifically, the pH of the water is lower than 3-4, in water, all the carbon dioxide is present as dissolved carbon dioxide (dissolved CO _2).

When carbon dioxide is sent from the reaction unit 4 into the liquid storage unit 5, since the internal liquid in the liquid storage unit 5 is alkaline and has a high pH, the carbon dioxide sent into the liquid storage unit 5 is Dissolves in contact with internal liquid. The carbon dioxide remains in the liquid storage unit 5.
Then, the reaction control unit 111 repeats the control from step S102 to step S105 a predetermined number of times (a predetermined number of times). The predetermined number of times may be set to an arbitrary number by the user operating the operation unit 105.

  That is, the inorganic carbon of the sample is removed, and the operation of generating carbon dioxide by heating the sample is repeated a predetermined number of times. And all of the carbon dioxide which generate | occur | produces repeatedly is melt | dissolved in the internal liquid of the liquid storage part 5. FIG. In this way, the liquid storage unit 5 captures carbon dioxide generated in the reaction unit 4.

When the control from step S102 to step S105 by the reaction control unit 111 is repeated a predetermined number of times (YES in step S106: reaction control step), the pH control unit 112 operates the injection unit 3 to operate the acid solution supply unit 22. Then, the acid solution is collected in the syringe body 31 of the injection unit 3 through the acid solution suction channel 10. Furthermore, the pH controller 112 adds (drops) the acid solution collected in the syringe body 31 to the internal liquid of the liquid reservoir 5 via the adjustment liquid transfer channel 14 by operating the injection unit 3. (Step S107: pH adjustment step). Thereby, the internal liquid of the liquid storage part 5 becomes acidic.
In this example, 0.2 ml of HCl (1N) is added to the internal liquid in the liquid reservoir 5. As a result, the pH of the internal liquid in the liquid reservoir 5 becomes about 2.

  When the internal liquid in the liquid storage unit 5 becomes acidic (pH becomes low) and the internal liquid is bubbled by the carrier gas supplied into the liquid storage unit 5, it dissolves in the internal liquid in the liquid storage unit 5. The carbon dioxide that has been extracted is extracted at once (see equation (1)).

  Then, the amount of carbon dioxide discharged from the discharge pipe 102 is detected by the detection unit 7, and the total organic carbon (TOC concentration) contained in the sample is calculated by the calculation processing unit 113 (step S108). The calculated total organic carbon (TOC concentration) is displayed on the display unit 106 by the display processing unit 114.

  Further, in the above-described operation, the amount of the internal liquid of the liquid storage unit 5 is increased by adding the acid solution and the alkali solution. In this case, the internal liquid exceeding a certain amount is discharged from the second drain channel 19 to the outside.

4). Action and Effect (1) In the present embodiment, the pH control unit 112 operates the injection unit 3 to add an alkaline solution to the internal liquid of the liquid storage unit 5 (step S101), and the internal liquid of the liquid storage unit 5 To make it alkaline. In this state, the reaction control unit 111 operates the injection unit 3 to supply the sample from which the inorganic carbon has been removed into the combustion tube 42 of the reaction unit 4 (step S105). Then, carbon dioxide corresponding to the amount of organic matter (total carbon) contained in the sample is generated in the combustion tube 42. Carbon dioxide generated in the combustion pipe 42 is supplied to the liquid storage unit 5 by the flow of the carrier gas. Carbon dioxide from the reaction unit 4 is dissolved in the internal liquid by contacting the internal liquid in the liquid storage unit 5. And the pH control part 112 operates the injection | pouring part 3, adds an acid solution to an internal liquid (step S107: pH adjustment step), and makes the internal liquid of the liquid storage part 5 acidic. Then, carbon dioxide dissolved in the internal liquid of the liquid reservoir 5 is extracted at a time. The detection unit 7 detects the carbon dioxide.

Therefore, by operating the injection unit 3 under the control of the pH control unit 112 to make the internal liquid of the liquid storage unit 5 alkaline, carbon dioxide generated over a long period of time in the reaction unit 4 is reduced inside the liquid storage unit 5. It can be dissolved and retained in the liquid. And after that, the injection | pouring part 3 is operated by control of the pH control part 112, and the internal liquid of the liquid storage part 5 is made acidic, The carbon dioxide which is melt | dissolving in an internal liquid can be extracted at once. Moreover, in the detection part 7, the carbon dioxide extracted at once can be detected.
As a result, the detection time in the detection unit 7 can be shortened, and the detection sensitivity can be improved.
Therefore, the measurement accuracy in the all organic carbon measuring device 1 can be improved.

(2) Moreover, in this embodiment, the carbon dioxide from the reaction part 4 bubbles the internal liquid in the liquid storage part 5. FIG.
Therefore, carbon dioxide generated in the reaction unit 4 can be efficiently dissolved in the internal liquid of the liquid storage unit 5.

(3) Moreover, in this embodiment, the liquid storage part 5 is comprised by the IC reactor.
Therefore, the liquid storage part 5 is utilized using the existing member in the total organic carbon measuring apparatus 1.
Can be configured.
As a result, an increase in the number of parts in the total organic carbon measuring device 1 can be suppressed.

(4) Further, in the present embodiment, the reaction control unit 111 operates in the state where the injection unit 3 is operated under the control of the pH control unit 112, and the internal liquid in the liquid storage unit 5 is made alkaline. Generate carbon multiple times. The pH control unit 112 makes the internal liquid acidic after carbon dioxide generated a plurality of times by the reaction control unit 111 is introduced into the liquid storage unit 5 and dissolved in the internal liquid of the liquid storage unit 5. The carbon dioxide in the internal liquid is extracted at once.

  In the total organic carbon measuring device 1, the larger the amount of the sample sent to the reaction unit 4, the more carbon dioxide is detected by the detection unit 7, and as a result, the measurement accuracy of the total organic carbon is improved. . On the other hand, the reaction part 4 has a restriction | limiting in a magnitude | size and a shape for the reason on a structure. For this reason, the amount of the sample that can be sent to the reaction unit 4 is limited, and the amount of carbon dioxide detected by the reaction unit 4 is also limited.

Therefore, in the total organic carbon measurement device 1, carbon dioxide is generated from the reaction unit 4 a plurality of times under the control of the reaction control unit 111 while the internal liquid of the liquid storage unit 5 is made alkaline. The carbon dioxide generated multiple times is dissolved in the internal liquid of the liquid reservoir 5 and remains in the liquid reservoir 5. When the injection unit 3 is operated under the control of the pH control unit 112 and the internal liquid of the liquid storage unit 5 is acidified, carbon dioxide dissolved in the internal liquid of the liquid storage unit 5 is extracted at a time. .
Therefore, the amount of carbon dioxide detected by the detection unit 7 can be increased.
As a result, the detection sensitivity in the detection unit 7 can be improved.

(5) Moreover, in this embodiment, the liquid storage part 5 stores the internal liquid within a fixed amount. In the liquid reservoir 5, the internal liquid exceeding a certain amount is discharged from the second drain channel 19 to the outside.

Therefore, even if an internal solution increases by adding an acid solution and an alkaline solution to the internal liquid of the liquid storage part 5, the internal liquid exceeding a fixed amount can be discharged | emitted from a drain flow path outside.
As a result, the amount of the internal liquid in the liquid storage unit 5 can be kept constant.

5. In the above description, the IC reactor in the total organic carbon measuring device 1 is configured as the liquid storage unit 5. However, the IC reactor and the liquid reservoir 5 may be configured separately by providing the liquid reservoir 5 on the rear side of the IC reactor. In this case, when the sample is added to the IC reactor in which the acidic solution is stored while the internal liquid in the liquid storage unit 5 is made alkaline, the inorganic carbon contained in the sample reacts with the acidic solution and is oxidized. Carbon is generated. The generated carbon dioxide is dissolved in the internal liquid in the liquid reservoir 5. After that, when the internal liquid of the liquid storage unit 5 is acidified, carbon dioxide is extracted from the internal liquid.

  In the above description, the reaction control unit 111 has been described as generating carbon dioxide a plurality of times in the reaction unit 4 (the control from step S102 to step S105 is repeated). However, the reaction control unit 111 starts from step S102. The control up to step S105 may be performed only once.

  In the above description, the carbon dioxide from the reaction unit 4 has been described as being dissolved in the internal liquid by bubbling the internal liquid in the liquid storage unit 5. However, the method of dissolving the carbon dioxide from the reaction unit 4 in the internal liquid of the liquid storage unit 5 is not limited to this. For example, a flow path is formed in the liquid storage section 5 by a film having gas permeability (gas permeability), and carbon dioxide from the reaction section 4 passes through the flow path, thereby allowing the liquid storage section 5 to A structure in which carbon dioxide is dissolved in the internal liquid may be used.

  In the above description, the reaction unit 4 has been described as a so-called combustion type (dry type) oxidation unit in which a sample is heated by a high-temperature electric furnace 41. However, the reaction unit 4 may be a so-called wet oxidation unit that chemically oxidizes a sample using ultraviolet rays and an oxidizing agent. However, as compared with the wet type, the combustion-type total organic carbon measuring device has a characteristic that the oxidizing power with respect to the organic matter is strong, but the measurement accuracy of the low concentration sample is low. Therefore, if the present invention is applied to a combustion-type total organic carbon measuring device, both oxidizing power and measurement accuracy can be achieved.

  In the above description, the sample is described as being a liquid, but the sample may be a solid.

  In the above description, the configuration in which the processing in steps S101 to S108 in FIG. 3 is automatically performed under the control of the control unit 110 has been described. However, at least a part of these steps S101 to S108 is manually performed by the user. It may be done at.

DESCRIPTION OF SYMBOLS 1 Total organic carbon measuring device 3 Injection | pouring part 4 Reaction part 5 Liquid storage part 7 Detection part 19 2nd drain flow path 110 Control part 111 Reaction control part 112 pH control part

Claims (10)

A total organic carbon measuring device for measuring total organic carbon contained in a sample,
A reaction part for generating carbon dioxide from inorganic carbon or total carbon contained in the sample;
A detection unit for detecting carbon dioxide generated in the reaction unit;
A liquid storage part provided between the reaction part and the detection part, in which an internal liquid that can contact carbon dioxide generated in the reaction part is stored;
A pH adjuster for adjusting the pH of the internal liquid stored in the liquid reservoir,
When the carbon dioxide is introduced into the liquid storage part from the reaction part, the pH adjusting part makes the internal liquid stored in the liquid storage part alkaline, thereby generating carbon dioxide in the internal liquid. A total organic carbon measuring device, wherein the carbon dioxide in the internal liquid is extracted by dissolving and then acidifying the internal liquid.   The total organic carbon measurement device according to claim 1, wherein the liquid storage unit bubbles carbon dioxide generated in the reaction unit in the internal liquid.   The liquid storage section is configured by an IC reactor that stores an acid solution as the internal liquid and generates carbon dioxide by reacting inorganic carbon contained in a sample with an acid solution. Item 3. The total organic carbon measuring device according to Item 2. In a state where the internal liquid stored in the liquid storage unit is made alkaline by the pH adjusting unit, the reaction control unit further includes a reaction control unit that generates carbon dioxide a plurality of times in the reaction unit,
The pH adjusting unit is configured to acidify the internal liquid after carbon dioxide generated a plurality of times by the reaction control unit is introduced into the liquid storage unit and dissolved in the internal liquid stored in the liquid storage unit. The total organic carbon measuring device according to any one of claims 1 to 3, wherein carbon dioxide in the internal liquid is extracted.   The total organic carbon measurement device according to claim 4, wherein the liquid storage unit stores the internal liquid within a predetermined amount and discharges the internal liquid exceeding the predetermined amount to a drain flow path. A reaction unit that generates carbon dioxide from inorganic carbon or total carbon contained in the sample, and a detection unit that detects carbon dioxide generated in the reaction unit, and is included in the sample based on the detection result in the detection unit A carbon dioxide extraction method using a total organic carbon measuring device for measuring total organic carbon,
A liquid storage step of storing an internal liquid that can be contacted with carbon dioxide generated in the reaction unit in a liquid storage unit provided between the reaction unit and the detection unit;
A pH adjustment step of adjusting the pH of the internal liquid stored in the liquid storage part,
In the pH adjustment step, when carbon dioxide is introduced from the reaction unit into the liquid storage unit, the internal liquid stored in the liquid storage unit is made alkaline, so that carbon dioxide is contained in the internal liquid. A carbon dioxide extraction method characterized in that carbon dioxide in the internal liquid is extracted by dissolving and then acidifying the internal liquid.   The carbon dioxide extraction method according to claim 6, wherein the liquid storage unit bubbles carbon dioxide generated in the reaction unit in the internal liquid.   The liquid storage section is configured by an IC reactor that stores an acid solution as the internal liquid and generates carbon dioxide by reacting inorganic carbon contained in a sample with an acid solution. Item 8. The carbon dioxide extraction method according to Item 7. In the state where the internal liquid stored in the liquid storage part is made alkaline by the pH adjustment step, the reaction part further includes a reaction control step of generating carbon dioxide a plurality of times in the reaction part,
In the pH adjustment step, carbon dioxide generated a plurality of times in the reaction control step is introduced into the liquid storage part and dissolved in the internal liquid stored in the liquid storage part, and then the internal liquid is acidified. The carbon dioxide extraction method according to any one of claims 6 to 8, wherein carbon dioxide in the internal liquid is extracted. The carbon dioxide extraction method according to claim 9, wherein the liquid storage unit stores the internal liquid within a certain amount and discharges the internal liquid exceeding the certain amount to a drain flow path.

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