JP6710951B2 - Water quality analyzer - Google Patents

Description

The present invention relates to a water quality analyzer for analyzing a sample solution of river water, lake water, seawater, rainwater, groundwater, and the like, as well as water and sewage water, pharmaceutical water, pure water, industrial water, wastewater, etc. The present invention relates to a total organic carbon meter that measures the concentration of TOC (total organic carbon) in a solution.

2. Description of the Related Art In recent years, for pollution investigations and the like, measurement of TOC concentration contained in sample water solutions for water and sewage, various plant waters, rivers, etc. has become one of the important items.
The most general measuring method for measuring the TOC concentration in such a sample aqueous solution is to use TC (total carbon) in the sample aqueous solution by using a non-dispersion type infrared gas detector (NDIR detector) for detecting the CO ₂ concentration. ) Concentration and IC (inorganic carbon) concentration are individually measured, and the TOC concentration is calculated based on the following formula (1).
TC=TOC+IC (1)

FIG. 4 is a schematic configuration diagram showing an example of a general TOC meter (total organic carbon meter).
The TOC meter 101 includes a sample introduction tube 20, a sample injection part 30, a TC oxidation part (TC conversion part) 40, an IC reaction part (IC conversion part) 50, a carrier for the sample injection part 30 and the TC oxidation part 40. A carrier gas control unit 60 for supplying gas, a dehumidifier 70, an NDIR detector 80 serving as a detection unit for detecting CO ₂ concentration information, and a control unit 190 are provided (for example, refer to Patent Document 1).

The sample injection unit 30 includes a syringe pump 31 having a volume of 5 ml and a rotary valve 33 having 4 ports. The sample water sampling port (first connection part) of the rotary valve 33 is connected to the sample introduction pipe (for example, a PTFE tube having an inner diameter of 0.5 mm) 20, and the TC injection port (second connection part) of the rotary valve 33 is It is connected to the TC oxidation unit 40, the IC injection port (third connection part) of the rotary valve 33 is connected to the IC reaction unit 50, and the common port (fourth connection part) of the rotary valve 33 is the syringe pump 31. Is connected with. The rotary valve 33 connects the sample introduction pipe 20 and the syringe pump 31, connects the TC oxidation unit 40 and the syringe pump 31, and connects the IC reaction unit 50 and the syringe pump 31. It has become.

The syringe pump 31 includes a cylindrical syringe 31a, a cylindrical plunger 31b inserted into the syringe 31a, and a pulse motor 32 that moves the plunger 31b in the vertical direction. The syringe pump 31 is adapted to inject the sample aqueous solution into the syringe 31a when the plunger 31b is pulled downward while being connected to the sample introduction tube 20. Further, when the plunger 31b is pushed upward while the TC oxidation unit 40 and the syringe pump 31 are connected (TC measurement state), a predetermined amount (for example, 1 ml) of the sample aqueous solution in the syringe 31a is supplied to the TC oxidation unit 40. It is supposed to be done. Further, when the plunger 31b is pushed upward while the IC reaction unit 50 and the syringe pump 31 are connected (IC measurement state), a predetermined amount (for example, 1 ml) of the sample aqueous solution in the syringe 31a is supplied to the IC reaction unit 50. It is supposed to be done.

The TC oxidation part 40 includes a TC combustion tube 41 made of quartz glass, a TC furnace 42 arranged around the TC combustion tube 41 and heated to about 680° C., a carrier gas introduction mechanism 43, a slider 45, and a drain tube. And 46 (see FIG. 2).
A well-known oxidation catalyst 44 is filled in the TC combustion pipe 41, the TC injection port of the rotary valve 33 is connected to the slider 45, and the lower end of the TC combustion pipe 41 is the upper end of the IC reaction part 50. Is connected with.

The carrier gas introduction mechanism 43 is a plate-shaped member and is installed at the upper end of the TC combustion tube 41. Inside the plate-shaped member, there is a circular tube-shaped sample flow channel 43a that penetrates in the up-down direction and a left-right direction. And a carrier gas flow path 43b having a circular pipe shape formed in the above.
According to such a carrier gas introduction mechanism 43, the carrier gas (for example, high-purity air) flowing leftward in the carrier gas flow passage 43b is directed downward in the TC combustion tube 41 at 150 ml/min. When the sample aqueous solution flows downward in the sample flow channel 43a, the TOC in the sample aqueous solution is evaporated and decomposed by the TC furnace 42 and reaches the oxidation catalyst 44 together with the carrier gas for oxidation. The catalyst 44 oxidizes to CO ₂ . The CO ₂ is guided to the IC reaction section 50 together with the carrier gas.

The slider 45 is a plate-shaped body, and a sample channel 45a penetrating in the vertical direction is formed inside the slider 45. The slider 45 is movable (sliding) in the left-right direction, and the sample flow channel 45a is located at either the upper end of the sample flow channel 43a of the carrier gas introducing mechanism 43 or the upper end of the drain pipe 46. It is supposed to be placed in.

The IC reaction unit 50 includes a resin IC reactor 51 in which a 25% phosphoric acid aqueous solution (acid) is placed. The IC injection port of the rotary valve 33 is connected to the upper end of the IC reactor 51, and the outlet at the upper end of the IC reactor 51 is connected to the dehumidifier 70. Further, the lower end of the IC reactor 51 is connected to the lower end of the TC oxidation unit 40 so that the carrier gas is bubbled in the 25% phosphoric acid aqueous solution (acid) inside the IC reactor 51. There is. As a result, the IC in the sample aqueous solution becomes CO ₂ .
This CO ₂ is guided to the NDIR detector 80 via the dehumidifier 70 together with the carrier gas.

Control unit 190, an acquiring unit 90a that acquires the CO ₂ concentration information from NDIR detector 80, and a TC calculation section 90b for calculating the TC concentration from the CO ₂ concentration information in TC measurement, the CO ₂ concentration information of the IC measurement It has an IC calculation unit 90c that calculates the IC concentration from the above, a TOC calculation unit 90d that calculates the TOC concentration using Equation (1), and a sample injection unit control unit 190e that controls the sample injection unit 30.

By the way, the sample aqueous solution is stored in a sample container with a septum in order to prevent contamination from the outside. Such a sample container S with a septum is composed of a cylindrical 40 ml glass container (sample container) having a bottom surface and a silicon septum attached to the opening of the glass container.

Therefore, when analyzing the sample aqueous solution with the TOC meter 101, the stainless water sampling needle (for example, inner diameter 0.5 mm, outer diameter 1.6 mm) 21 formed at the tip of the sample introduction tube 20 is penetrated through the septum. Then, an operation of sucking a set amount (for example, 1 ml) of the sample aqueous solution from the sample container S with the septum into the syringe 31a is performed. Further, in order to continuously and automatically analyze a large number of sample aqueous solutions, an autosampler including a turntable in which a large number of septum-equipped sample containers S are arranged may be used.

JP, 2001-337082, A

However, when the stainless water sampling needle 21 penetrates the silicon septum, there is almost no gap between the outer peripheral surface of the water sampling needle 21 and the septum, and the airtightness is very high. When 1 ml) or more of the sample aqueous solution is collected, the pressure in the sample container S with a septum decreases. Therefore, after collecting a certain amount or more of the sample aqueous solution from the septum-equipped sample container S, the sample aqueous solution cannot be continuously sampled from the same sample container.

Therefore, in addition to the water sampling needle, an air bleeding needle is provided to allow the water sampling needle and the air bleeding needle to penetrate the septum, and a double tube structure water sampling needle is used to create a gap between the inner tube and the outer tube. It is conceivable to remove the air from the tank or to provide a groove on the outside of the water sampling needle. However, each of these methods has a problem that the manufacturing cost is high, and that the outside air (ambient atmosphere) enters the sample container S with a septum and the sample aqueous solution is contaminated from the outside air.

The applicant has studied a water quality analyzer capable of collecting a sample solution from a sample container with a septum and then collecting the sample solution from the sample container with a septum, without incurring manufacturing costs. did.
Therefore, before collecting the sample solution from the sample container with a septum, the carrier gas used for the sample injection part or the like is supplied into the sample container through a water sampling needle for collecting the sample solution. It was found to increase the pressure inside.

That is, the water quality analyzer of the present invention collects a sample solution in a sample container, a sample injection part for supplying a predetermined amount of the sample solution, and a water collecting needle is formed at the tip part, and the end part is the sample. A sample introduction pipe connected to an injection part, a TC conversion part connected to the sample injection part and converting all carbon in the sample solution into carbon dioxide, connected to the sample injection part and the TC conversion part, An IC conversion unit for converting inorganic carbon in the sample solution into carbon dioxide, a detection unit connected to the IC conversion unit for detecting carbon dioxide, and a carrier gas for the sample injection unit and/or the TC conversion unit. a water quality analyzer and a carrier gas control unit for supplying the carrier gas controller supplies the carrier gas to the sample introduction tube via the sample injection part, thereby through said water sampling needle The carrier gas is supplied into the sample container.

Here, the “predetermined amount” is an arbitrary amount determined by the measurer or the like for analysis by the TC conversion unit or the IC conversion unit, and is, for example, 1 ml.

As described above, according to the water quality analyzer of the present invention, since the pressure in the sample container after collecting a certain amount or more of the sample solution from the sample container with the septum does not decrease, the sample container with the septum is continuously supplied. Then, the sample solution can be collected. Further, since it is not necessary to add a new mechanism, it can be realized without manufacturing cost. Furthermore, it is possible to prevent the sample from being contaminated by the surrounding atmosphere.

(Means and effects for solving other problems)
Further, in the above invention, the sample container is a sample container with a septum, after penetrating the water sampling needle septum of the septum with the sample container, supplying a set amount of the carrier gas to the sample container, A control unit for collecting the set amount of the sample solution from the sample container may be provided.
As described above, according to the water quality analyzer of the present invention, since it is supplied to the sample introduction tube through the sample injection part, a substantially set amount of carrier gas, which is the amount of sampling the sample solution from the sample container, is supplied. be able to.

Further, in the above invention, an autosampler in which a plurality of sample containers with septa are arranged may be provided.

The schematic block diagram which shows the TOC meter which is an example of the water quality analyzer which concerns on this invention. Sectional drawing which shows the structural example of the TC oxidation part in FIG. 3 is a flowchart illustrating an analysis method using the TOC meter shown in FIG. 1. The schematic block diagram which shows an example of a general TOC meter.

Embodiments of the present invention will be described below with reference to the drawings. Needless to say, the present invention is not limited to the embodiments described below, and various modes are included without departing from the spirit of the present invention.

As a structural example of the water quality analyzer according to the present invention, a TOC meter (total organic carbon meter) is taken as an example, and its schematic structure is shown in FIG. 2 is a cross-sectional view showing an example of the TC oxidation part in FIG. The same parts as those of the TOC meter 101 described above are designated by the same reference numerals, and the description thereof will be omitted.
The TOC meter 1 supplies the carrier gas to the autosampler 10, the sample introduction tube 20, the sample injection part 30, the TC oxidation part 40, the IC reaction part 50, the sample injection part 30 and the TC oxidation part 40. Carrier gas controller 60, dehumidifier 70, NDIR detector 80 serving as a detector for detecting CO ₂ concentration information, and controller 90.

The autosampler 10 includes a water sampling needle drive unit 11 for moving the water sampling needle 21 in the vertical direction, a turntable 12 in which a large number of septum-equipped sample containers S are arranged, and a turntable for moving the turntable 12. The table drive unit 13 is well known.

Control unit 90, an acquisition unit 90a to acquire the CO ₂ concentration information from NDIR detector 80, and a TC calculation section 90b for calculating the TC concentration from the CO ₂ concentration information in TC measurement, the CO ₂ concentration information of the IC measurement From the IC calculation unit 90c that calculates the IC concentration, the TOC calculation unit 90d that calculates the TOC concentration using Equation (1), the sample injection unit control unit 90e that controls the sample injection unit 30, and the autosampler 10 are controlled. And an automatic sampler controller 90f for

Here, an example of an analysis method for analyzing one sample aqueous solution using the TOC meter 1 described above will be described with reference to the flowchart of FIG. In the actual measurement operation, a co-washing operation of the syringe 31a and the sample introduction tube 20 with the sample aqueous solution is performed, but the description thereof will be omitted and only the operation which is the main point of the present invention will be described.

First, in the process of step s101, the sample injection unit control unit 90e controls the rotary valve 33 to bring the TC oxidation unit 40 and the syringe pump 31 into a connected state (TC measurement state).

Next, in the process of step s102, the sample injection unit control unit 90e injects 3 ml of the carrier gas into the syringe 31a by pulling the plunger 31b downward.
Next, in the process of step s103, the sample injection unit control unit 90e controls the rotary valve 33 to bring the sample introduction tube 20 and the syringe pump 31 into a connected state (sample introduction state).

Next, in the process of step s104, the sample injection unit control unit 90e injects 1 ml of the carrier gas into the sample introduction tube 20 by pushing the plunger 31b upward. That is, the inside of the sample introduction tube 20 is purged with the carrier gas.
Next, in the process of step s105, the autosampler control unit 90f controls the water sampling needle drive unit 11 to insert the water sampling needle 21 into the septum of the septum-equipped sample container S to insert the water sampling needle 21. The tip end of is placed near the bottom (in the sample aqueous solution) in the sample container S with a septum.

Next, in the process of step s106, the sample injection unit controller 90e pushes the plunger 31b upward to discharge 2 ml of the carrier gas through the sample introduction tube 20. As a result, 2 ml (set amount) of carrier gas is injected into the sample container S with a septum.
Next, in the process of step s107, the sample injection unit controller 90e pulls the plunger 31b downward to collect 2 ml (set amount) of the sample aqueous solution via the sample introduction tube 20. As a result, 1 ml of the sample aqueous solution is injected into the syringe 31a.

Next, in the process of step s108, the sample injection unit control unit 90e controls the rotary valve 33 to bring the TC oxidation unit 40 and the syringe pump 31 into a connected state (TC measurement state).
Next, in the process of step s109, the sample injection unit control unit 90e injects 1 ml of the sample aqueous solution into the TC oxidation unit 40 by pushing the plunger 31b upward.
Next, in the process of step s110, TC measurement is performed.

Then, after the TC measurement is performed, in the process of step s111, the sample injection unit control unit 90e injects 3 ml of the carrier gas into the syringe 31a by pulling the plunger 31b downward.
Next, in the process of step s112, the sample injection unit control unit 90e controls the rotary valve 33 to bring the sample introduction tube 20 and the syringe pump 31 into a connected state (sample introduction state).

Next, in the process of step s113, the sample injection unit control unit 90e pushes the plunger 31b upward to discharge 3 ml of carrier gas through the sample introduction tube 20. As a result, 2 ml (set amount) of carrier gas is injected into the sample container S with a septum.
Next, in the process of step s114, the sample injection unit control unit 90e pulls the plunger 31b downward to collect 2 ml (set amount) of the sample aqueous solution via the sample introduction tube 20. As a result, 1 ml of the sample aqueous solution is injected into the syringe 31a.

Next, in the process of step s115, the sample injection unit control unit 90e controls the rotary valve 33 to bring the IC reaction unit 50 and the syringe pump 31 into a connected state (IC measurement state).
Next, in the processing of step s116, the sample injection unit control unit 90e injects 1 ml of the sample aqueous solution into the IC reaction unit 50 by pushing the plunger 31b upward.
Next, in the process of step s117, IC measurement is performed.
Then, when the process of step s117 is completed, this flowchart is ended.

As described above, according to the TOC meter 1 of the present invention, the pressure in the sample container after collecting a predetermined amount or more of the sample aqueous solution from the sample container S with the septum does not decrease, so Can continuously collect the sample aqueous solution. Further, since it is not necessary to add a new mechanism, it can be realized without manufacturing cost. Furthermore, it is possible to prevent the sample from being contaminated by the surrounding atmosphere.

The present invention is a total organic carbon for measuring the TOC concentration in a sample solution such as river water, lake water, seawater, rainwater, groundwater, etc., as well as water, sewage water, pharmaceutical water, pure water, industrial water, drainage water, etc. It can be used for water quality analyzers such as meters.

1 TOC meter (water quality analyzer)
20 sample introduction pipe 21 water sampling needle 30 sample injection part 40 TC oxidation part (TC conversion part)
50 IC reaction part (IC conversion part)
60 carrier gas control unit 80 NDIR detector (detection unit)

Claims (3)

A sample injection unit for collecting the sample solution in the sample container and supplying a predetermined amount of the sample solution,
A water sampling needle is formed on the tip portion, and a sample introduction tube whose end portion is connected to the sample injection portion,
A TC conversion unit connected to the sample injection unit for converting all carbon in the sample solution into carbon dioxide;
An IC conversion unit that is connected to the sample injection unit and the TC conversion unit and converts inorganic carbon in the sample solution into carbon dioxide;
A detection unit that is connected to the IC conversion unit and detects carbon dioxide;
A water quality analyzer comprising: a carrier gas control unit that supplies a carrier gas to the sample injection unit and/or the TC conversion unit,
The carrier gas control unit supplies the carrier gas to the sample introduction tube via the sample injection part, thereby characterized in that for supplying the carrier gas through the water sampling needle into the sample container Water quality analyzer. The sample container is a sample container with a septum,
After penetrating the water sampling needle septum of the septum with the sample container, the supply setting amount of the carrier gas into the sample container, a control unit for collecting the sample solution in the set amount from the sample container The water quality analyzer according to claim 1, wherein The water quality analyzer according to claim 2, further comprising an autosampler in which a plurality of septum-equipped sample containers are arranged.

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