Device and method for continuously and automatically measuring inorganic carbon dissolved in solution

Abstract

The invention discloses a device and a method for continuously and automatically measuring inorganic carbon dissolved in a solution. The device comprises a gas inlet system, a sample injection system, a reaction tank, a waste liquid tank, a condensation system and a carbon dioxide detection system, a sample inlet and a gas outlet are formed in the upper part of the reaction tank, the sample injection system is communicated with the reaction tank through the sample inlet, one end of the condensation system is communicated with the reaction tank through the gas outlet, and the other end of the condensation system is communicated with the carbon dioxide detection system; an air inlet and a waste liquid outlet are formed in the lower part of the reaction tank, the air inlet system is communicated with the reaction tank through the air inlet, and the waste liquid outlet is communicated with the waste liquid tank through the sample injection system. The device is high in automation degree, capable of continuously measuring dissolved inorganic carbon, capable of continuously and automatically measuring samples for multiple times, high in accuracy, high in response speed, capable of meeting the requirement for continuous measurement of multiple samples and suitable for various water environments.

Description

Technical Field

[0001] The invention relates to the technical field of water quality monitoring, and in particular to a device and method for continuously and automatically measuring inorganic carbon dissolved in a solution. Background Art

[0002] Dissolved Inorganic Carbon (DIC) refers to the total concentration of various inorganic carbonates, bicarbonates, carbonic acid and carbon dioxide gases dissolved in water, and is an important chemical parameter of marine and inland waters. Accurate and rapid determination of the content of dissolved inorganic carbon is of great significance for understanding the absorption, transformation and migration of carbon dioxide by water, as well as global climate change and carbon cycle research.

[0003] Although existing methods for determining dissolved inorganic carbon, such as coulometric titration and infrared analysis, have high accuracy, they are complex to operate, expensive, and can usually only be used in laboratory environments, and cannot achieve in-situ, continuous determination. Summary of the invention

[0004] In order to solve the problems existing in the background technology, the present invention provides a device and method for continuously and automatically measuring the inorganic carbon dissolved in a solution.

[0005] The technical solution adopted by the present invention is:

[0006] 1. A device for continuously and automatically measuring the dissolved inorganic carbon in a solution:

[0007] It includes an air intake system, an injection system, a reaction pool, a waste liquid pool, a condensation system and a carbon dioxide detection system; an injection port and an air outlet are provided at the upper part of the reaction pool, the injection system is connected with the reaction pool through the injection port, one end of the condensation system is connected with the reaction pool through the air outlet, and the other end of the condensation system is connected with the carbon dioxide detection system; an air intake port and a waste liquid discharge port are provided at the lower part of the reaction pool, the air intake system is connected with the reaction pool through the air intake port, and the waste liquid discharge port is connected with the waste liquid pool through the injection system.

[0008] The air intake system includes a nitrogen bottle, a drying tube I and a flow monitor. The gas delivery port of the nitrogen bottle is connected to one end of the drying tube I through a pipeline, and the other end of the drying tube I is connected to the air intake port of the reaction tank through a pipeline. A flow monitor is provided in the pipeline between the drying tube I and the reaction tank.

[0009] The gas entering the drying tube I from the gas delivery port of the nitrogen cylinder through the pipeline is used as the input gas. The drying tube I is provided with a desiccant I for drying the input gas and absorbing carbon dioxide in the input gas. The desiccant I is mainly composed of a mixture of soda lime and calcium chloride particles. The mass ratio of soda lime and calcium chloride particles is 1:1. The input gas is nitrogen.

[0010] The injection system includes a sample stage, a water sample acid inlet and an injection pump. The sample stage is connected to one end of the injection pump through the water sample acid inlet, and the other end of the injection pump is connected to the reaction tank; the waste liquid discharge port is connected to the waste liquid tank through a pipeline through the injection pump.

[0011] The water sample acid inlet includes a water pipe, a sample tube and an acid tube, one end of which is respectively connected to containers storing water, sample solution and phosphoric acid solution in the sample station, and the other end of which is respectively connected to various interfaces of the injection pump.

[0012] The condensation system includes a condenser, a drying tube II and a filter tip, the gas outlet of the reaction tank is connected to one end of the condenser through a pipeline, the other end of the condenser is connected to the drying tube II through a pipeline, and then the drying tube II is connected to one end of the filter tip for filtering particulate matter through a pipeline;

[0013] The gas discharged from the gas outlet of the reaction tank is used as the output gas. The drying tube II is provided with a desiccant II for drying the output gas. The desiccant II is mainly calcium chloride.

[0014] The carbon dioxide detection system includes a solenoid valve, an infrared detector and a waste gas bottle; the solenoid valve is a three-way valve, one end of the solenoid valve is connected to the other end of the filter in the condensation system, and the other two ends of the solenoid valve are connected to the waste gas bottle, and an airway is provided between the other two ends of the solenoid valve and the waste gas bottle, one of which is connected to the waste gas bottle through the infrared detector, and the other is directly connected to the waste gas bottle; a single-chip microcomputer and a relay are also installed in the solenoid valve, one end of the relay is electrically connected to the single-chip microcomputer, and the other end of the relay is electrically connected to the solenoid valve body.

[0015] It also includes a control system, which is communicatively connected with the air intake system, the sample injection system and the carbon dioxide detection system.

[0016] The control system includes a control circuit and a computer. The flow monitor in the air intake system, the injection pump in the injection system, the solenoid valve and the infrared detector in the carbon dioxide detection system all communicate with the computer serial port through the control circuit.

[0017] 2. A method for determining dissolved inorganic carbon in a solution based on a device for continuously and automatically determining dissolved inorganic carbon in a solution:

[0018] The method comprises the following steps:

[0019] S1. Add water, several sample solutions and phosphoric acid solution into the sample stage, open the integrated graphical interface in the computer and turn on the nitrogen bottle;

[0020] S2. The computer controls the opening of the flow monitor and the solenoid valve to introduce nitrogen from the gas delivery port of the nitrogen bottle to the gas inlet of the reaction pool until the air in the reaction pool and each pipeline is emptied;

[0021] S3, the computer controls to close the flow monitor and start the injection pump, the injection pump draws distilled water from the sample station and adds it to the reaction pool through the injection port, then the injection pump draws the liquid in the reaction pool from the reaction pool and adds it to the waste liquid pool through the waste liquid discharge port, then the injection pump draws one of the sample solutions from the sample station and adds it to the reaction pool through the injection port, then the injection pump draws the liquid in the reaction pool from the reaction pool and adds it to the waste liquid pool through the waste liquid discharge port;

[0022] S4, the syringe pump again draws the same sample solution as in step S3 from the sample station and adds it to the reaction cell through the injection port, then the syringe pump draws excess phosphoric acid solution from the sample station and adds it to the reaction cell through the injection port, the computer controls the flow monitor to start nitrogen filling into the reaction cell, and the added sample solution reacts with the added phosphoric acid solution;

[0023] S5, the gas generated by the reaction in step S4 is pushed by the nitrogen gas to enter the condenser, drying tube II and filter tip in sequence, the water condensed in the condenser flows back to the reaction tank through the gas outlet, the gas after passing through the filter tip enters the infrared detector through the electromagnetic valve, the infrared detector transmits the detected carbon dioxide concentration data to the computer, the carbon dioxide concentration data is processed by the computer to generate a waveform, the peak area of ​​the waveform is calculated, and the content of dissolved inorganic carbon in the solution is obtained;

[0024] S6, the injection pump draws distilled water from the sample station and adds it to the reaction pool through the injection port to clean the reaction pool; then the injection pump draws the liquid in the reaction pool from the reaction pool and adds it to the waste liquid pool through the waste liquid discharge port;

[0025] S7, looping steps S2-S6 until the determination of various sample solutions is completed.

[0026] Preferably, the mass fraction of the phosphoric acid solution is 8.5%.

[0027] The beneficial effects of the present invention are:

[0028] 1. It realizes the continuous determination of dissolved inorganic carbon, can automatically measure samples continuously for many times, can control parameters such as air flow rate and reaction time, and improves the determination efficiency and accuracy.

[0029] 2. The device has a simple structure, is easy to operate, and its components are very easy to replace, maintain and service.

[0030] 3. The measurement accuracy is high and the response speed is fast. It can meet the needs of continuous measurement of multiple samples and has a high degree of automation. The code written in Python and the graphical interface can realize the whole process of automated measurement, which can be completed without unnecessary operations and is easy to get started.

[0031] 4. It is applicable to various water environments, not limited to seawater, and not even limited to the determination of DIC, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the device of the present invention.

[0033] Figure 2 This is an exploded diagram of the model of the reaction pool in the device.

[0034] Figure 3 This is a graphical control interface diagram.

[0035] Figure 4 This is a graph showing the change in carbon dioxide gas concentration over time.

[0036] Figure 5 This is a comparison chart of the data measured by the two DIC devices in Comparative Example 1.

[0037] In the figure: 1. water sample acid inlet, 2. injection pump, 3. reaction tank, 4. condenser, 5. drying tube II, 6. filter tip, 7. solenoid valve, 8. nitrogen bottle, 9. drying tube I, 10. flow monitor, 11. computer, 12. infrared detector, 13. waste liquid tank, 14. waste gas bottle. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. These implementation cases are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0039] Embodiments of the present invention are as follows:

[0040] Example 1

[0041] This embodiment assembled a device for continuously and automatically measuring the dissolved inorganic carbon in a solution. The structural schematic diagram of the device is shown in FIG. Figure 1 As shown, it includes an air intake system, a sample injection system, a reaction tank 3, a waste liquid tank 13, a condensation system and a carbon dioxide detection system;

[0042] The model explosion diagram of the reaction pool 3 in this device is as follows Figure 2As shown, an inlet and an outlet are provided at the upper part of the reaction pool 3, the injection system is connected to the reaction pool 3 through the inlet, one end of the condensation system is connected to the reaction pool 3 through the outlet, and the other end of the condensation system is connected to the carbon dioxide detection system; an inlet and a waste liquid discharge port are provided at the lower part of the reaction pool 3, the inlet system is connected to the reaction pool 3 through the inlet, and the waste liquid discharge port is connected to the waste liquid pool 13 through the injection system.

[0043] The air intake system includes a nitrogen bottle 8, a drying tube Ⅰ9 and a flow monitor 10. The gas delivery port of the nitrogen bottle 8 is connected to one end of the drying tube Ⅰ9 through a pipeline, and the other end of the drying tube Ⅰ9 is connected to the air intake port of the reaction tank 3 through a pipeline. A flow monitor 10 for monitoring and controlling the gas flow is provided in the pipeline between the drying tube Ⅰ9 and the reaction tank 3.

[0044] The gas entering the drying tube Ⅰ9 from the gas delivery port of the nitrogen bottle 8 through the pipeline is used as the input gas. The drying tube Ⅰ9 is provided with a desiccant Ⅰ for drying the input gas and absorbing the carbon dioxide in the input gas. The desiccant Ⅰ is mainly composed of soda lime and calcium chloride particles mixed in a mass ratio of 1:1. The input gas is nitrogen. High-purity nitrogen is continuously delivered to the drying tube Ⅰ9 from the gas delivery port of the nitrogen bottle 8. The nitrogen is dried by the desiccant Ⅰ and then delivered to the reaction tank 3. At the same time, the flow rate of the nitrogen is monitored and controlled by the flow monitor 10.

[0045] The sample injection system includes a sample stage, a water sample acid inlet 1 and a syringe pump 2. The sample stage is connected to one end of the syringe pump 2 through the water sample acid inlet 1, and the other end of the syringe pump 2 is connected to the reaction pool 3.

[0046] The waste liquid discharge port is connected to the waste liquid pool 13 through a pipeline through the injection pump 2 . Specifically, the injection pump 2 can extract waste liquid from the reaction pool 3 through the waste liquid discharge port and then discharge it into the waste liquid pool 13 .

[0047] More specifically, the injection pump 2 has 9 interfaces. When measuring three sample solutions, interfaces 7-9 are connected to the three sample solutions in the sample stage, interface 6 is connected to the phosphoric acid in the sample stage, interface 5 is connected to the injection port of the reaction pool 3, interface 4 is connected to the distilled water in the sample stage, interface 3 is connected to the waste liquid outlet of the reaction pool 3, and interface 2 is connected to the waste liquid pool 13.

[0048] The injection pump 2 adopts an industrial injection pump with model number HG-GZSB-10-09-60.

[0049] The water sample acid inlet 1 is a multi-channel pipeline, including a water pipe, a sample pipe and an acid pipe. One end of the water pipe, the sample pipe and the acid pipe are respectively connected to the containers storing water, sample solution and phosphoric acid in the sample station, and the other end of the water pipe, the sample pipe and the acid pipe are respectively connected to the various interfaces of the injection pump 2.

[0050] In the specific implementation, water, sample solution and phosphoric acid are added to the containers in the sample stage respectively, and then enter the interfaces of the injection pump through the water pipe, sample pipe and acid pipe respectively, and are controlled by the injection pump and injected into the reaction pool 3.

[0051] The condensation system includes a condenser 4, a drying tube II 5 and a filter 6. The gas outlet of the reaction tank 3 is connected to one end of the condenser 4 through a pipeline, and the other end of the condenser 4 is connected to the drying tube II 5 through a pipeline. Then, the drying tube II 5 is connected to one end of the filter 6 for filtering particulate matter through a pipeline.

[0052] The gas discharged from the gas outlet of the reaction pool 3 is used as the output gas. The drying tube II 5 is provided with a desiccant II for drying the output gas. The desiccant II is mainly calcium chloride.

[0053] The carbon dioxide detection system includes a solenoid valve 7, an infrared detector 12 and a waste gas bottle 14;

[0054] The solenoid valve 7 is a three-way valve, one end of the solenoid valve 7 is connected to the other end of the filter 6 in the condensation system, and the other two ends of the solenoid valve 7 are directly or indirectly connected to the waste gas bottle 14. There is an airway between the other two ends of the solenoid valve 7 and the waste gas bottle 14, one of which is connected to the waste gas bottle 14 through the infrared detector 12, and the other is directly connected to the waste gas bottle 14;

[0055] The solenoid valve 7 is also equipped with a single chip microcomputer and a relay. One end of the relay is electrically connected to the single chip microcomputer to receive the control signal of the single chip microcomputer, and the other end of the relay is electrically connected to the valve body of the solenoid valve 7 to control the opening or closing of each valve port of the solenoid valve 7.

[0056] It also includes a control system, which is communicatively connected with the air intake system, the sample injection system and the carbon dioxide detection system.

[0057] The control system includes a control circuit and a computer 11,

[0058] The flow monitor 10 in the air intake system, the injection pump 2 in the sample injection system, the solenoid valve 7 and the infrared detector 12 in the carbon dioxide detection system all communicate with the computer 11 serial port through the control circuit.

[0059] Graphical control interface as shown below: Figure 3 As shown, in a specific implementation, a graphical control interface is made by using python and pyqt5 on a computer 11, and serial communication is used to control the switch of the solenoid valve 7, the operation of the injection pump 2, the flow control of the flow monitor 10 and the data received from the infrared detector 12, so that a carbon dioxide peak graph can be obtained, and a graph is drawn according to the data in ppm transmitted by the sensor and the graph area is integrated and calculated, thereby obtaining the content of inorganic carbon dissolved in the solution.

[0060] The method for continuously and automatically determining dissolved inorganic carbon in a solution using the device comprises the following steps:

[0061] S1, adding distilled water, several sample solutions and phosphoric acid into the sample stage, opening the integrated graphical interface in the computer 11 and opening the nitrogen bottle 8;

[0062] S2, the computer 11 controls the opening of the flow monitor 10 and the solenoid valve 7, and nitrogen is introduced from the gas delivery port of the nitrogen bottle 8 to the gas inlet of the reaction pool 3 to exhaust the air in the reaction pool 3 and each pipeline;

[0063] S3, the computer 11 controls to close the flow monitor 10 and to start the injection pump 2, the injection pump 2 extracts distilled water from the sample station and adds it to the reaction pool 3 through the injection port, then the injection pump 2 extracts the liquid in the reaction pool 3 from the reaction pool 3 and adds it to the waste liquid pool 13 through the waste liquid discharge port, then the injection pump 2 extracts one sample solution among several sample solutions from the sample station and adds it to the reaction pool 3 through the injection port, then the injection pump 2 extracts the liquid in the reaction pool 3 from the reaction pool 3 and adds it to the waste liquid pool 13 through the waste liquid discharge port;

[0064] More specifically, when measuring the sample solution connected to the interface 7 of the injection pump 2: distilled water is extracted from the interface 4 of the injection pump 2 and added to the reaction pool 3 from the interface 5; the liquid in the reaction pool 3 is extracted from the interface 3 of the injection pump 2 and added to the waste liquid pool 13 from the interface 2; the sample solution is extracted from the interface 7 of the injection pump 2 and added to the reaction pool 3 from the interface 5.

[0065] S4, the syringe pump 2 again extracts the same sample solution as in step S3 from the sample station and adds it to the reaction cell 3 through the injection port, then the syringe pump 2 extracts excess phosphoric acid from the sample station and adds it to the reaction cell 3 through the injection port, the computer 11 controls the flow monitor 10 to start and fill nitrogen into the reaction cell 3, and the added sample solution reacts with the added phosphoric acid;

[0066] More specifically, the working process of the syringe pump 2 when adding the sample solution is similar to that in step S3 ; phosphoric acid in the sample station is extracted from the interface 6 of the syringe pump 2 and added to the reaction cell 3 from the interface 5 .

[0067] S5, the gas generated by the reaction in step S4 is pushed by the nitrogen gas charged into the condenser 4, the drying tube II 5 and the filter 6 in sequence, the water condensed in the condenser 4 flows back to the reaction tank 3 through the gas outlet, the gas after passing through the filter 6 enters the infrared detector 12 through the electromagnetic valve 7, the infrared detector 12 transmits the detected carbon dioxide concentration data to the computer 11, the carbon dioxide concentration data is processed by the computer 11 to generate a waveform, the peak area of ​​the waveform is calculated, and the content of dissolved inorganic carbon in the solution is obtained;

[0068] S6, the injection pump 2 draws distilled water from the sample stage and adds it to the reaction pool 3 through the injection port to clean the reaction pool 3; then the injection pump 2 draws the liquid in the reaction pool 3 from the reaction pool 3 and adds it to the waste liquid pool 13 through the waste liquid discharge port;

[0069] S7, looping steps S2-S6 until the determination of various sample solutions is completed.

[0070] Example 2

[0071] According to the method described in Example 1, using the device described in Example 1, tap water is used as the sample solution to measure it, and the obtained carbon dioxide gas concentration changes with time as shown in the figure Figure 4 As shown, by integrating and calculating the image, it can be found that the DIC in tap water is approximately 2.4 mg / L.

[0072] Comparative Example 1

[0073] The device was named DIC1, and the commercially available device that could not automatically and continuously measure samples was named DIC2. Samples 1 to 10 were measured by DIC1 and DIC2. The results are shown in the figure. Figure 5 As shown, it can be seen that the difference between the data measured by the two is small, and the error is less than 0.5%, which can illustrate the accuracy of the data measured by the present invention.

[0074] When DIC1 is used for measurement, the measurement time for each sample is about 3 minutes, and when DIC2 is used for measurement, the measurement time for each sample is about 4 to 5 minutes, which can indicate that the measurement speed of the present invention is relatively fast.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the method of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A device for continuously and automatically measuring the dissolved inorganic carbon in a solution, characterized in that: The invention comprises an air intake system, an injection system, a reaction pool (3), a waste liquid pool (13), a condensation system and a carbon dioxide detection system; the upper part of the reaction pool (3) is provided with an injection port and an air outlet, the injection system is connected to the reaction pool (3) through the injection port, one end of the condensation system is connected to the reaction pool (3) through the air outlet, and the other end of the condensation system is connected to the carbon dioxide detection system; the lower part of the reaction pool (3) is provided with an air intake port and a waste liquid discharge port, the air intake system is connected to the reaction pool (3) through the air intake port, and the waste liquid discharge port is connected to the waste liquid pool (13) through the injection system.

2. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 1, characterized in that: The air intake system comprises a nitrogen bottle (8), a drying tube I (9) and a flow monitor (10); the gas delivery port of the nitrogen bottle (8) is connected to one end of the drying tube I (9) through a pipeline; the other end of the drying tube I (9) is connected to the air intake port of the reaction tank (3) through a pipeline; and a flow monitor (10) is arranged in the pipeline between the drying tube I (9) and the reaction tank (3).

3. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 2, characterized in that: The gas entering the drying tube I (9) from the gas delivery port of the nitrogen bottle (8) through the pipeline is used as the input gas. The drying tube I (9) is provided with a desiccant I for drying the input gas and absorbing carbon dioxide in the input gas. The desiccant I is mainly composed of a mixture of soda lime and calcium chloride particles, and the mass ratio of the soda lime to the calcium chloride particles is 1:

1. The input gas is nitrogen.

4. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 1, characterized in that: The sample injection system comprises a sample stage, a water sample acid inlet (1) and an injection pump (2); the sample stage is connected to one end of the injection pump (2) through the water sample acid inlet (1), and the other end of the injection pump (2) is connected to the reaction pool (3); the waste liquid discharge port is connected to the waste liquid pool (13) through a pipeline through the injection pump (2).

5. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 4, characterized in that: The water sample acid inlet (1) comprises a water pipe, a sample pipe and an acid pipe, one end of each of which is connected to containers storing water, sample solution and phosphoric acid solution in the sample station, and the other end of each of which is connected to various interfaces of the injection pump (2).

6. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 1, characterized in that: The condensation system comprises a condenser (4), a drying tube II (5) and a filter tip (6); the gas outlet of the reaction tank (3) is connected to one end of the condenser (4) through a pipeline, the other end of the condenser (4) is connected to the drying tube II (5) through a pipeline, and then the drying tube II (5) is connected to one end of the filter tip (6) for filtering particulate matter through a pipeline; The gas discharged from the gas outlet of the reaction pool (3) is used as the output gas. The drying tube II (5) is provided with a desiccant II for drying the output gas. The desiccant II is calcium chloride.

7. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 6, characterized in that: The carbon dioxide detection system comprises a solenoid valve (7), an infrared detector (12) and a waste gas bottle (14); the solenoid valve (7) is a three-way valve, one end of the solenoid valve (7) is connected to the other end of the filter tip (6) in the condensation system, and the other two ends of the solenoid valve (7) are connected to the waste gas bottle (14); an airway is provided between the other two ends of the solenoid valve (7) and the waste gas bottle (14), one of which is connected to the waste gas bottle (14) through the infrared detector (12), and the other is directly connected to the waste gas bottle (14); a single-chip microcomputer and a relay are also installed in the solenoid valve (7), one end of the relay is electrically connected to the single-chip microcomputer, and the other end of the relay is electrically connected to the valve body of the solenoid valve (7).

8. The device for continuously and automatically measuring dissolved inorganic carbon in a solution according to claim 1, characterized in that: It also includes a control system, which is communicatively connected with the air intake system, the sample injection system and the carbon dioxide detection system.

9. A device for continuously and automatically measuring dissolved inorganic carbon in a solution according to any one of claims 2, 4, 7 or 8, characterized in that: The control system comprises a control circuit and a computer (11); the flow monitor (10) in the air intake system, the injection pump (2) in the sample injection system, the solenoid valve (7) and the infrared detector (12) in the carbon dioxide detection system all communicate with the computer (11) via a serial port through the control circuit.

10. A method for determining dissolved inorganic carbon in a solution based on the device according to any one of claims 1 to 9: The method comprises the following steps: S1, adding water, several sample solutions and phosphoric acid solution into the sample stage, opening the integrated graphical interface in the computer (11) and opening the nitrogen bottle (8); S2, the computer (11) controls the opening of the flow monitor (10) and the solenoid valve (7), and nitrogen is introduced from the gas delivery port of the nitrogen bottle (8) to the gas inlet of the reaction pool (3) to exhaust the air in the reaction pool (3) and each pipeline; S3, the computer (11) controls the flow monitor (10) to be turned off and the injection pump (2) to be turned on, the injection pump (2) extracts distilled water from the sample station and adds it to the reaction pool (3) through the injection port, then the injection pump (2) extracts the liquid in the reaction pool (3) from the reaction pool (3) and adds it to the waste liquid pool (13) through the waste liquid discharge port, then the injection pump (2) extracts one sample solution from the sample station and adds it to the reaction pool (3) through the injection port, then the injection pump (2) extracts the liquid in the reaction pool (3) from the reaction pool (3) and adds it to the waste liquid pool (13) through the waste liquid discharge port; S4, the syringe pump (2) again extracts the same sample solution as in step S3 from the sample stage and adds it to the reaction cell (3) through the injection port, then the syringe pump (2) extracts excess phosphoric acid solution from the sample stage and adds it to the reaction cell (3) through the injection port, the computer (11) controls the flow monitor (10) to start and fill nitrogen into the reaction cell (3), and the added sample solution reacts with the added phosphoric acid solution; S5, the gas generated by the reaction in step S4 is pushed by the nitrogen gas to enter the condenser (4), the drying tube II (5) and the filter (6) in sequence, the water condensed in the condenser (4) flows back to the reaction tank (3) through the gas outlet, the gas after passing through the filter (6) enters the infrared detector (12) through the electromagnetic valve (7), the infrared detector (12) transmits the detected carbon dioxide concentration data to the computer (11), the carbon dioxide concentration data is processed by the computer (11) to generate a waveform, the peak area of ​​the waveform is calculated, and the content of dissolved inorganic carbon in the solution is obtained; S6, the injection pump (2) draws distilled water from the sample stage and adds it to the reaction pool (3) through the injection port to clean the reaction pool (3); then the injection pump (2) draws the liquid in the reaction pool (3) from the reaction pool (3) and adds it to the waste liquid pool (13) through the waste liquid discharge port; S7, looping steps S2-S6 until the determination of various sample solutions is completed.

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