JPH07119749B2 - Sample introduction device for carbon analyzer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sample introduction device for a carbon analyzer. More specifically, total carbon (TC), total organic carbon (TOC), inorganic carbon (IC), volatile organic carbon (POC) in various liquid samples.
The present invention relates to a sample introduction device in a carbon analyzer capable of quantifying the like.

(B) Conventional technology Conventionally, a method using a carbon analyzer, particularly an organic carbon analyzer (TOC meter), has been performed for water quality analysis of rivers, lakes, seawater, etc. The content is used to evaluate the pollution degree of water quality.

Such TOC quantification is usually performed using a combustion TOC meter, and the typical method is to measure the TOC value by subtracting the IC value from the TC value. To
Since the IC component is contained in a significantly larger amount than the TOC component,
There is a large error in the measured TOC value.

Therefore, a method is generally used in which a sample is subjected to aeration under acidic conditions to remove IC components (single product components and carbon dioxide) in advance and then introduced into a TOC meter for measurement. As a device for carrying out such a method, a TOC meter equipped with a pretreatment device as shown in FIG. 4 is used. In the figure, the sample is introduced into the pretreatment tank through the sample introduction channel 29 and the switching valve 28, and the acid solution (such as dilute hydrochloric acid) supplied from the acid container 41 through the pump 26 and the acid introduction channel 23. Mixed, where gas introduction path
It is aerated by nitrogen gas or purified air introduced through 25.

A part of the sample, which has been aerated for a predetermined time (usually 5 to 10 minutes) to remove the carbonic acid component and the carbon dioxide, flows into the TOC-based combustion tube 16 through the sample transfer channel 24 by the pump 27 through the sample measuring means 30. The introduced and existing organic matter is converted into carbon dioxide by combustion, and this is transferred to the detector 19 via the gas-liquid separator 18 by the carrier gas from the carrier gas introduction pipe 25. Then, by measuring the amount of carbon dioxide by the detector, the corresponding TOC value will be measured. As the sample measuring means 30, so-called slide valve, loop valve for liquid chromatograph, syringe pump, etc. are used, and the introduced amount to be measured is usually 20 to 400 μm.
Met.

(C) Problems to be solved by the invention However, in such a conventional TOC meter system, since the sample weighing means and the pretreatment tank are independent of each other,
There is a drawback that aeration treatment is required for a significantly large amount of sample compared to the actual amount introduced into the TOC meter, which increases the amount of acid used during aeration and the amount of aeration gas introduced. Further, there is a problem that the flow path configuration of the apparatus is complicated and that the sample easily passes through the pretreatment system and the sample measuring system because the sample passes therethrough.

The present invention has been made to solve such problems, and in particular, carbon analysis with a pretreatment function and a metering function that can significantly reduce the amount of acid and aeration gas used and have a simpler flow path configuration. An object is to provide a sample introduction device for measurement.

(D) Means for Solving the Problems Thus, according to the present invention, (a) a sample suction channel connectable to the sample introduction part, and (b) an acid suction channel connectable to an acid container, c) a sample transfer channel that can be directly connected to the sample inlet of the carbon analyzer, (d) a gas inlet / outlet channel, and (e)
Selectively a syringe type metering pump having a suction and discharge port located above, (f) a suction and discharge port of the syringe type metering pump (e), and any one of the flow paths (a) to (d). Provided is a sample introduction device for a carbon analyzer, which comprises a switching means to be connected and (g) a gas introduction means capable of aerating a liquid introduced into a syringe type metering pump (e).

The sample transfer flow path (c) and the gas introduction / extrusion path (d) may be configured to be switchable in the same pipe line. In this case, for example, when setting the sample transfer flow path (c), the tip of the pipe line is It may be configured so that it is connected to the sample introduction part and the tip of the conduit is switched to the open position when the gas introduction / exhaust path (d) is set.

Further, the gas introduction / exhaust path (d) is normally connected to the exhaust port, but it may be connected to the detection part of the carbon analyzer through a switching means, thereby independently measuring the total amount of IC and POC. It becomes possible to do it. At this time, a concentration column may be provided in the system, and POC can be measured by inserting a column of carbon dioxide absorbent (soda lime, lithium hydroxide, etc.). It is possible. Further, the gas introduction / exhaust path (d) may be connected to the carrier gas flow path of the carbon analyzer through a column of a packing material (activated carbon etc.) capable of trapping a POC component such as hydrocarbon, whereby the IC and IC It is also possible to measure each POC independently. In any case, according to the sample introduction device of the present invention, by changing the tip of the gas introduction / exhaust path (d) variously, it becomes possible to easily perform IC and POC measurements other than TOC measurement.

(E) Action By switching the switching means and sucking with the syringe type metering pump, the required amount of sample from the sample suction channel and the required amount of acid solution from the acid suction channel are introduced into the pump, and further gas Gas is introduced from the introduction and discharge passage.

By introducing the aeration gas from the gas introduction means in this state, the aeration of the mixed liquid is efficiently performed. Then, the mixed liquid after aeration is introduced into the carbon analyzer through the sample transfer flow path by the discharge of the pump and is used for the measurement of TOC.

(F) Example FIG. 1 shows the TOC of the sample introduction apparatus of one example of the present invention.
It is a structure explanatory view shown with the connection structure with a meter. In the figure, a sample introduction device 1 includes a sample suction passage 3 connected to a sample introduction portion 31 having a sample container, an acid suction passage 4 connected to an acid container 41, and a sample introduction device of a combustion type carbon analyzer 2. A sample transfer flow path 5 directly connected to the portion 13, a gas introduction / exhaust path 6 whose end is open to the atmosphere, a syringe type metering pump 7 having a suction / discharge port 71 located above, and a switch for assembling these. It is basically composed of means 8. Here, the switching means 8 includes a connection flow path 74 from the suction / discharge port 71 of the pump 7, and any one of the sample suction flow path 3, the acid suction flow path 4, the sample transfer flow path 5 and the gas introduction / discharge path 6. It consists of a 5-port switching valve for selecting and connecting.

On the other hand, the syringe type metering pump 7 is composed of a syringe barrel 72 having an internal volume of about 1.5 ml, a plunger 73 sliding on the syringe barrel 72, and a plunger driving means 75 for moving the plunger up and down to perform suction and discharge operation. Done and plunger 73
A gas introduction passage 9 connected to the aeration gas supply pipe 11 via a valve 10 is provided in the center of the inside of the cylinder, so that the aeration gas can be introduced from the tip of the plunger 73 into the syringe barrel 72. is there.

However, the gas introduction passage 9 does not necessarily have to be provided in the plunger, and may be connected, for example, below the syringe barrel.

In addition, as shown in the figure, the combustion type carbon analyzer 2 holds the combustion catalyst 12 below the sample introducing part 13 and also uses a heater.
A combustion pipe 16 provided with 17 is arranged, and a gas-liquid separator 18 and a non-dispersion type infrared detector 29 are further provided at the subsequent stage of the combustion pipe 16. However, the connection end of the sample transfer flow path 5 is switched by the slider 14 between a connection position to the sample introduction part 13 (a position shown in the figure; hereinafter a sample introduction position) and a connection position to the discharge pipe 20 (hereinafter a discharge position). Is configured. In the figure, reference numeral 15 is a drive motor for the slider 14, and 21 is a carrier gas supply path.

The operation of the sample introduction device 1 will be described.

First, with the slider 14 of the combustion type carbon analyzer 2 in the discharge position, the sample is sucked by the syringe type measuring pump 7 with the switching means 8 at the position shown in the figure, and then the switching means 8 is switched to switch the inside of the pump 7. The sample is discharged from the suction / discharge port 71 through the sample transfer flow path 5 to the discharge pipe 20 by pressing the plunger 73. This is repeated a predetermined number of times to co-wash the system with the sample (initial setting operation).

Then, a predetermined amount of sample (for example, 200 μ) is sucked into the syringe-type metering pump 7 with the switching means 8 at the position shown in the figure, and then the switching means 8 is switched to the acid suction flow path 4 so that a certain amount of acid solution Aspirate 1N hydrochloric acid 10μ). The acid solution is filled up to the port of the switching means 8, which makes it possible to suck an accurate amount of the acid solution.

After that, the switching means 8 is switched to the connection position to the gas introduction / exhaust passage 6, and a predetermined amount of air is sucked so that a void is formed above the acidified sample. The amount of air introduced is set to an amount such that the sample in the pump 7 does not scatter from the suction / discharge port 7 to the outside during aeration described later, and is 100 μ in this embodiment. In this state, the valve 10 is opened and the aeration gas is introduced into the pump 7 through the gas introduction passage 9. This state is shown in FIG. In the figure, A indicates an acidified sample. Here, nitrogen was used as the aeration gas, the aeration rate was 20 ml / min, and the aeration time was 3 to 5 minutes. As a result, carbon dioxide in the sample is diffused into the atmosphere from the gas introduction / exhaust path 6 and the IC
The component removal process is completed.

In this state, the switching means 8 is switched to the sample transfer channel 5, and the aeration gas is introduced for a predetermined time. As a result, the untreated sample remaining in the flow path 5 is discharged through the discharge pipe 20.

After that, set the slider 14 to the sample introduction position and set the plunger.
Combustion tube that pushes up 73 and treats processed sample through channel 5
Installed within 16. At this time, the processed sample that may remain in the flow path 5 can be introduced into the combustion pipe 16 by introducing the aeration gas as a pressure-feeding gas after the sample in the pump 7 is discharged. It becomes possible to use the treated sample of (1) for analysis. However, since the dead volume such as the flow path 5 is relatively small because the pipe system is not complicated, the treated sample remaining therein does not have to be used for analysis. In that case, the actual sample injection amount is an amount obtained by subtracting the sample amount remaining in the flow path 5 from the sample amount measured by the pump 7.

The sample introduced into the combustion tube 16 in this manner is vaporized,
The TOC component is converted to carbon dioxide when burned. This carbon dioxide is transferred to the gas-liquid separator 18 by the carrier gas (purified air or oxygen) together with the water generated by combustion, the water is removed there, and then transferred to the detector 19 based on its infrared absorption intensity. The CO2 concentration and eventually the TOC value are calculated.

Note that the sample introduction device 1 can also measure IC and POC.

That is, after the initial setting, the sample in the flow path 5 is discharged to the discharge pipe 20 by introducing the aeration gas before the sample is introduced, and the sample 7 is sucked into the pump 7 and the acid is sucked in the same manner as described above. . After this, the carrier gas supplied from the carrier gas supply path 21 through the sample transfer flow path 5 is introduced into the pump 7. Here, the carrier gas is used instead of the above-mentioned air in order to avoid mixing of carbon dioxide in the atmosphere. Therefore, if a purifier for the carbon dioxide absorbent is provided in the gas introduction / exhaust passage 6, it is possible to introduce air using the introduction / exhaust passage as described above.

Next, the aeration gas is introduced in the same manner as described above, but at this time, the switching means 8 is connected to the sample transfer channel 5 side. As a result, the IC component and POC component in the sample are introduced into the combustion tube 16 together with the aeration gas, and all become carbon dioxide. Therefore, by comparing the peak area and peak height under standard conditions, the IC in the sample (the total amount of IC and POC if POC is present) can be quantified.

After that, the sample is introduced into the combustion tube 16 and the TOC is measured as described above.

FIG. 3 is a view corresponding to FIG. 1 showing a sample introduction device of another embodiment of the present invention. In the figure, the configuration is the same as that of the above embodiment except that the gas introduction / exhaust passage 6 is connected between the combustion pipe 16 and the gas-liquid separator 18 via the gas trap column 61 and the three-way valve 62. ing. By using such a sample introduction device, TOC can be measured in the same manner as described above,
Accurate quantification of the IC alone is possible even if the POC component is present in the sample. That is, the gas due to aeration is trapped in the gas trap column 61, but the gas component, i.e., IC, trapped by heating the column 61 after that.
Carbon dioxide and POC components generated from the components are released, and the three-way valve 62 is set to the solid line position, so that the gas-liquid separator
These are transferred to the detector 19 through 18, but the detector 19
Detects only carbon dioxide. Therefore, the aerated gas can be used independently for the measurement of IC components. At this time, the gas trap column 61 is not always necessary,
It is preferable to insert it in order to obtain a sharper detection peak.

In order to measure the IC component and the POC component independently of each other, a packed column that passes carbon dioxide and traps the POC component is inserted in the gas introduction / exhaust pipe 6 so that it can be switched and connected to the sample introduction port. Can be configured as. As a result, the IC component in the first aerated gas can be measured independently, and then the POC component can be measured independently by heating the packed column and introducing it into the combustion tube. On the contrary, by inserting a carbon dioxide absorbent such as soda lime or lithium hydroxide into the gas introduction / exhaust pipe 6, it is possible to independently measure only the POC component.

In any case, according to the sample introduction device of the present invention, since the gas after aeration can be effectively used, it can be used not only for TOC but also for measurement of IC, POC and the like. Especially when the sample contains a POC component, the TOC measured value shows a correspondingly small value,
By independently measuring the POC component from the aeration gas and adding it to the TOC value, it is possible to make a correction corresponding to the POC component reduced by the aeration process.

(G) Effect of the Invention According to the sample introduction device for a carbon analyzer of the present invention, pretreatment and measurement by aeration are performed by one syringe type pump. Therefore, since substantially only the necessary sample is subjected to the pretreatment, the consumption of acid and aeration gas is reduced and the treatment time is further shortened. Furthermore, the conventional pump for acid introduction and pretreatment for aeration are not required, and the flow channel structure can be remarkably simplified. Therefore, contamination is unlikely to occur.
Further, since the aeration gas discharged from the gas introduction / exhaust passage and the sample transfer passage can be effectively used, not only TOC but also IC and POC can be easily quantified.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing a sample introduction device of an embodiment of the present invention together with a connection structure with a TOC meter, FIG. 1 and 4 showing a sample introduction device of another embodiment of the invention,
It is a structure explanatory view which illustrates the conventional TOC measurement system. 1 ... Sample introduction device, 2 ... Combustion type carbon analyzer, 3 ... Sample suction passage, 4 ... Acid suction passage, 5 ... Sample transfer passage, 6 ... Gas introduction / exhaust passage, 7 ... … Syringe type metering pump, 8 …… Switching means, 9 …… Gas introduction path, 10 …… Valve, 11 …… Aeration gas introduction pipe, 31 …… Sample introduction part, 41 …… Acid container, 61 …… Ga Strap column, 62 ... 3-way valve, 71 ... Suction / discharge port, 72 ... Syringe barrel, 73 ... Plunger, 74 ... Connection channel, 75 ... Plunger drive means.

Claims (1)

[Claims] 1. A sample suction flow path that can be connected to a sample introduction section, a b) acid suction flow path that can be connected to an acid container, and a direct connection to a sample introduction section of a carbon analyzer. A sample transfer flow path, (d) a gas introduction / exhaust path, (e) a syringe type metering pump having a suction / discharge port positioned above, (f) a suction / discharge port of the syringe type metering pump (e) and the above Switching means for selectively connecting any one of the flow paths (a) to (d), and (g) gas introducing means capable of aerating the liquid introduced into the syringe type metering pump (e). A sample introduction device for a carbon analyzer provided.