JP3323891B2 - Gas diffusion flow injection analysis method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas diffusion flow injection analysis method and apparatus for use in, for example, the determination of ammonia nitrogen in environmentally polluted water.

[0002]

2. Description of the Related Art Conventionally, in this type of analysis by a gas diffusion method, as shown in FIG. 4, a sample solution flowing chamber 2 and a reagent solution flowing chamber 3 are arranged adjacent to each other with a gas permeable membrane 1 interposed therebetween. Using the gas diffusion cell 4 provided, the sample flow path 5 and the reagent flow path 6 communicating with each of the chambers 2 and 3 are provided with the fixed-quantity liquid supply pumps 7 and 7 respectively, and the reagent flow path 6 is provided downstream of the gas diffusion cell. , A photoinjector 8 equipped with a photometer 8 and a resistance coil 9 are used.

Then, a sample solution containing a gas to be measured or a sample solution in which a reaction reagent that generates a desired gas by reacting with the sample is mixed with the sample is sent into the sample channel 5. At the same time, a reagent solution containing a coloring reagent, which develops a color by diffusing a predetermined gas in the sample solution into the reagent flow path 6, is sent. , A predetermined gas is diffused into the reagent solution, and the color development at that time is analyzed by measuring with a photometer 8.

[0004]

In such a conventional method, a necessary reaction and gas diffusion are performed while flowing through the flow path at a constant speed. As the number of tanks needs to be large, the entire device must be large, and the amount of waste liquid after analysis increases, resulting in high costs for disposal and further water pollution. There were problems such as causing.

The present invention has been made in view of such a conventional problem,
A gas diffusion flow injection analysis method which shortens the time required for analysis, reduces the amount of reagent used, reduces the amount of waste liquid, and reduces the size of the apparatus, making it easy to bring it to the sample collection site for analysis. The purpose is to provide the device.

[0006]

SUMMARY OF THE INVENTION In order to solve the conventional problems as described above and to achieve the intended object, a feature of the method of the present invention is that a sample solution flow chamber and a reagent solution flow are separated by a gas permeable membrane. Using a gas diffusion cell having an extra chamber next to
The sample solution flows into the sample solution flow chamber, the reagent solution flows into the reagent solution flow chamber, the gas in the sample solution diffuses into the reagent solution through the gas permeable membrane, and the change in the reagent solution is measured with a photometer. In the gas diffusion flow injection analysis method, a piston having a capacity capable of accommodating an amount of solution necessary for at least one analysis is used as a pump for pumping each solution into the sample solution flow chamber and the reagent solution flow chamber. Using a pump-type sample liquid sending pump and a reagent liquid sending pump, each solution is sent into each of the chambers by operating the piston of each liquid sending pump in the pushing direction. Stop and stop the liquid feeding, and the sample solution flow chamber and / or
Alternatively, the flow path on the downstream side of the reagent solution flow chamber is closed, and then the pressure in the sample solution flow chamber and / or the pressure in the reagent solution flow chamber are reduced, so that the pressure difference between the two chambers is reduced. The gas diffusion flow injection analysis method is characterized in that the gas diffusion is performed while standing for a certain period of time and performing gas diffusion.

It is preferable that the pressure in the reagent solution flowing chamber is reduced by retracting the piston of the reagent feeding pump.

The apparatus of the present invention is characterized in that a gas diffusion cell having a sample solution flowing chamber and a reagent solution flowing chamber adjacent to each other with a gas permeable membrane interposed therebetween, and a sample solution flowing into the sample solution flowing chamber. Sample flow path, and a reagent flow path for flowing a reagent solution into the reagent solution flow chamber, and each of the flow paths is provided with a liquid sending pump, respectively, and downstream from a gas diffusion cell of the reagent flow path. Gas diffusion flow injection, in which a photometer is provided on the side, gas in the sample solution is diffused into the reagent solution through the gas permeable membrane in the gas diffusion cell, and changes in the reagent solution are measured with the photometer. In the analyzer, each of the liquid feed pumps has a capacity capable of storing an amount of solution necessary for at least one analysis, and the required amount of liquid is not supplied by the operation of the piston in the pushing direction. Together we are, using piston pump type pump liquid in the channel is sucked by the retraction of the piston, and the sample solution flow over chamber and /
Or, provided with an on-off valve to open and close the flow path on the downstream side of the gas diffusion cell of the reagent flow path, after sending each solution to each of the chambers by operating the piston of each liquid sending pump in the pushing direction, The operation of the two liquid feeding pistons is stopped to stop the liquid feeding, and at the same time, the flow path on the downstream side of the sample solution flow chamber and / or the reagent solution flow chamber is closed. By pressurizing and / or depressurizing the reagent solution flowing chamber, gas diffusion can be performed by stopping the apparatus for a certain period of time while maintaining a differential pressure between the two chambers.

In addition, a suction pump for reducing the pressure in the reagent solution flow chamber may be provided separately from the reagent sending pump.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS.
FIG. 2 will be described.

In FIG. 1, reference numeral 10 denotes a gas diffusion cell.
In the gas diffusion cell 10, a gas permeable membrane 11 is sandwiched in the center of a two-part housing, thereby partitioning the inside of the housing into a sample solution flow chamber 12 and a reagent solution flow chamber 13.

Each of the chambers 12 and 13 constitutes a part of the sample channel A and the reagent channel B, respectively.

The sample flow path A is a sample solution flow chamber 1
An on-off valve 14 for opening and closing the flow path is provided downstream of the sample solution 2, and a reaction coil 1 is provided upstream of the sample solution flow chamber 12.
5. Mixer 16, switching valve 17, and sample pump 1
8 are provided in order. The mixer 16 is in communication with a reaction reagent mixing channel C having a switching valve 19 and a reaction reagent pump 20 in this order.

Each of the liquid sending pumps 18 and 20 uses a piston-cylinder type pump having a capacity capable of storing an amount of each liquid necessary for at least one analysis, and the piston 2 is used as a pump.
1 is operated by means of a stepping motor 22 continuously or intermittently so that a constant amount of liquid is supplied.

As the switching valve 17, a rotary switching valve is used, a sample liquid supply pump 18 is connected to a common port 17a at the center of the rotor, and the first switching port 17b is connected to the common port 17a by rotation of the rotor. , A sample suction path 23 at the second switching port 17c, a washing liquid suction path 24 at the third switching port 17d,
The drainage passage 25 is connected to the fourth switching port 17e.

As the switching valve 19, a rotary switching valve is used. A reaction reagent delivery pump 20 is connected to a common port 19a at the center of the rotor, and the first switching port is connected to the common port 19a by rotation of the rotor. A mixer 16 is provided at 19b, a reaction reagent suction path 26 is provided at the second switching port 19c, and a washing liquid suction path 27 is provided at the third switching port 17d.
The drainage passage 28 communicates with the fourth switching port 17e.

In the reagent flow path B, a switching valve 30 and a reagent delivery pump 31 are sequentially provided upstream of the reagent solution flow chamber 13 of the gas diffusion cell 10, and downstream of the reagent solution flow chamber 13. , A photometer 38, an on-off valve 32, a pressure gauge 33, and a damper coil 34 are sequentially provided.

A liquid pump 31 is a piston-cylinder type pump having a capacity capable of storing an amount of each liquid necessary for at least one analysis, similarly to the above-described pumps. In this method, a constant-rate liquid supply is performed by operating the apparatus continuously or intermittently.

As the switching valve 30, a rotary switching valve is used, a reagent feeding pump 31 is connected to a common port 30a at the center of the rotor, and the first switching port 30b is connected to the common port 30a by the rotation of the rotor. The reagent solution flow chamber 13 of the gas diffusion cell 10, the reagent suction path 35 at the second switching port 30c, the washing liquid suction path 36 at the third switching port 30d, and the drainage path 37 at the fourth switching port 30e.
Is communicated.

The operation of each of the liquid feed pump, the switching valve, and the on-off valve of the apparatus having the above-mentioned configuration is automatically controlled in accordance with the setting conditions previously input to the computer.

In the drawing, reference numeral 39 denotes a constant temperature chamber.

Next, an analysis method using the gas diffusion flow injection device configured as described above will be described.

First, each switching valve 17, 19, 30 is operated to the position of the second switching port 17c, 19c, 30c, respectively, and in this state, each pump 18, 20, 31 is operated in the suction direction to perform one analysis. Aspirate the sample solution, sample reaction reagent, and color reagent solution required for the respective steps. Next, the respective pumps are stopped, and the respective switching valves 17, 19, 30 are respectively operated to the first switching ports 17b, 19b, 30b, respectively, and the pistons of the sample liquid supply pump 18 and the reaction reagent liquid supply pump 20 are traced (a few (equivalent to about µl of liquid)
Pushing operation is performed alternately. As a result, the sample solution and the reaction reagent are alternately fed in small amounts at 16 positions of the mixer, whereby the sample solution and the reaction reagent are mixed. While this passes through the reaction coil 15, a desired reaction proceeds, a gas required for detection is generated in the sample solution, and sent to the sample solution flow chamber 12 of the gas diffusion cell 10.

On the other hand, the reagent sending pump 30 is used to supply the coloring reagent solution to the reagent solution flowing chamber 13 in accordance with the time when the sample solution mixed with the reaction reagent is filled in the sample solution flowing chamber 12 of the gas diffusion cell 10. The liquid is supplied by continuously operating the piston in the pushing direction so that the pressure is satisfied.

In this way, when the sample solution flowing chamber 12 and the reagent solution flowing chamber 13 of the gas diffusion cell 10 are filled with the respective solutions, the respective liquid feeds are stopped.
The on-off valves 14 and 32 of the sample channel A and the reagent channel B are closed. Thereafter, the piston of the reagent sending pump 30 is retracted by a small amount to reduce the pressure in the reagent flow path B, so that the internal pressure in the reagent solution flowing chamber 13 becomes lower than that in the sample solution flowing chamber 12. So that a differential pressure can be brought about.

Contrary to the above-mentioned method of generating the differential pressure, the piston of the sample feed pump 18 is advanced by a small amount after the valves 14 and 32 are closed, whereby the sample solution flow chamber 12 is closed. The pressure on the side may be increased. Further, both the pressure reduction and the pressure increase operation may be performed.

In the method of depressurizing the reagent solution flow chamber side as compared with the case where the sample solution flow chamber side is pressurized, it is impossible to reduce the depressurization to a certain level or less. By doing so, simple means using a piston pump, such as reducing the pressure in the reagent solution flow chamber, is sufficient, and the apparatus can be simplified as compared with pressurization.

In the gas diffusion cell 10, the gas permeable membrane 11
At the same time as the sample solution and the reagent solution are filled in the two chambers 12 and 13 partitioned by the above, gas in the sample solution permeates the gas permeable membrane 11 and diffusion into the reagent solution is started. Since a low pressure difference between the chambers 12 and 13 on the reagent solution side is generated, gas permeation is promoted, and desired diffusion is performed in a short time.

In this way, the two chambers 12,
After stopping each solution in 13, each on-off valve 32 is opened,
By operating the piston of the reagent sending pump 30 in the pushing direction, the reagent solution in which the gas has been diffused is sent to the photometer, and the luminous intensity such as absorbance and fluorescence is measured to complete the analysis. After the measurement is completed, the switching valve and the liquid sending pump are appropriately operated to wash the inside of the flow path with the washing liquid.

When a sample solution in which a reaction reagent is previously mixed with a sample is used, or when a gas that is to be diffused into the sample itself is contained,
The reaction reagent mixing channel C is not used.

In the above-described example, the gas diffusion cell has a structure in which the center of the inside of the housing is partitioned by a flat gas-permeable membrane. In addition, as shown in FIG.
A tube-shaped gas-permeable membrane 41 made of a gas-permeable material is inserted concentrically at the center of the outer tube 40, and one of the inside and outside of the tube is used as a sample solution flow chamber, and the other is used as a reagent flow chamber. May be used.

In the above-described example, a differential pressure is generated in both chambers by moving the piston of the sample liquid sending pump 18 forward and / or retreating the piston of the reagent liquid sending pump 30. A piston-cylinder pump may be provided for each of the streams A and B.

In the above-described example, the mixing of the reaction reagent and the sample solution is performed by feeding the reaction reagent with the switching valve 19 and the reaction reagent pump 20. The liquid pump 31 may be used. In this case, as shown in FIG. 3, the switching valve 30 has fifth and sixth switching ports 30f and 30g.
The fifth switching port 30f communicates with the mixer 16 and the sixth reagent port 30g is connected to the reaction reagent suction path 2f.
7 is communicated. Then, the reaction reagent is supplied to the reagent delivery pump 3
After that, the pump 31 is alternately operated with the sample feeding pump 18 to feed the sample solution and the reaction reagent to the mixer 16 to mix the two solutions. After that, the liquid supply by both pumps is stopped, and the on-off valve 14 is closed.

After that, the switching valve 30 and the pump 31 are operated to clean the inside, and then the coloring reagent is used for the pump 31 to fill the reagent flowing chamber 13 and the analysis is performed in the same manner as described above.

In FIG. 4, parts that are the same as the example shown in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted.

[0036]

As described above, in the gas diffusion flow injection analysis method and apparatus according to the present invention, the sample solution flow chamber and the reagent solution flow chamber separated by the gas permeable membrane of the gas diffusion cell are respectively provided. As a pump for feeding the solution, a sample pump and a reagent pump of a piston pump type having a capacity capable of storing an amount of the solution necessary for at least one analysis are used, and a piston of each of the pumps is used. After each solution is fed into each of the chambers by operating in the pushing direction, the operation of both the liquid feeding pistons is stopped to stop the liquid feeding, and the sample solution flowing chamber and / or the downstream of the reagent solution flowing chamber are stopped. Close the side channel,
Thereafter, the sample solution flow chamber is pressurized and / or the reagent solution flow chamber is depressurized, so that a gas is diffused by being kept stationary for a certain period of time with a pressure difference between the two chambers. By doing so, gas diffusion is performed while each liquid is stationary, so that the amount of solution used is small, so the solution tank is also small, the overall apparatus can be downsized, and the amount of waste liquid mixed with reagents is small. And the processing becomes easy.

In addition, the amount of gas per unit time permeating through the gas permeable membrane can be increased by stopping both the liquids and providing a lower pressure difference in the reagent solution flow chamber than in the sample solution flow chamber. Analysis time can be shortened.

Further, by providing a suction pump for reducing the pressure in the reagent solution flow passage chamber separately from the reagent solution sending pump, control of the solution sending pump can be simplified.

[Brief description of the drawings]

FIG. 1 is a flow chart showing an example of an apparatus for performing the method of the present invention.

FIG. 2 is a sectional view showing another example of the gas diffusion cell of the above.

FIG. 3 is a flow chart showing another example of an apparatus for performing the method of the present invention.

FIG. 4 is a flow chart of a conventional device.

[Explanation of symbols]

 A sample flow path B reagent flow path C reaction reagent mixing flow path 10 gas diffusion cell 11 gas permeable membrane 12 sample solution flow chamber 13 reagent solution flow chamber 14 on-off valve 15 reaction coil 16 mixer 17 switching valve 17a common port 17b First switching port 17c Second switching port 17d Third switching port 17e Fourth switching port 18 Sample feeding pump 19 Switching valve 19a Common port 19b First switching port 19c Second switching port 19d Third switching port 19e Fourth switching port Reference Signs List 20 Reagent sending pump 21 Piston 22 Stepping motor 23 Sample suction path 24 Washing liquid suction path 25 Drainage path 26 Reaction reagent suction path 27 Cleaning liquid suction path 28 Drainage path 30 Switching valve 30a Common port 30b First switching port 30c Second Switching port 30d Third switching port 30e 4 switching port 30f fifth switching port 30g sixth switching port 31 reagent feeding pump 32 on-off valve 33 pressure gauge 34 damper coil 35 reagent suction path 36 washing liquid suction path 37 waste liquid path 38 photometer 39 constant temperature chamber 40 outer tube 41 gas permeation film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 21/75 G01N 21/00-21/61

Claims (4)

(57) [Claims] 1. A gas diffusion cell having a sample solution flow chamber and a reagent solution flow chamber adjacent to each other with a gas permeable membrane interposed therebetween, wherein a sample solution is placed in the sample solution flow chamber.
A gas diffusion flow injection analysis method comprising: flowing a reagent solution into a reagent solution flow chamber; diffusing gas in the sample solution into the reagent solution through a gas permeable membrane; and measuring a change in the reagent solution with a photometer. At least one pump is used to pump the respective solutions into the solution flow chamber and the reagent solution flow chamber.
Using a sample pump and a reagent pump of a piston pump type having a capacity capable of accommodating an amount of solution necessary for each analysis, the respective solutions are pumped by operating pistons of the respective pumps in the pushing direction. After being fed into each chamber, the operation of both the liquid feeding pistons is stopped to stop the liquid feeding, and the flow path on the downstream side of the sample solution flowing chamber and / or the reagent solution flowing chamber is closed, and thereafter, By pressurizing the sample solution flow chamber and / or depressurizing the reagent solution flow chamber, the gas diffusion is performed while the pressure is maintained between the two chambers for a certain period of time. Gas diffusion flow injection analysis method. 2. The gas diffusion flow injection method according to claim 1, wherein the pressure in the reagent solution flow chamber is reduced by retreating a piston of the reagent solution sending pump. 3. A gas diffusion cell having a sample solution flow chamber and a reagent solution flow chamber adjacent to each other with a gas permeable membrane interposed therebetween, a sample flow path for flowing a sample solution into the sample solution flow chamber, A reagent flow path for allowing a reagent solution to flow through the reagent solution flow chamber, and each of the flow paths includes a liquid sending pump, and a photometer downstream of the gas diffusion cell in the reagent flow path. In the gas diffusion flow injection analyzer, the gas in the sample solution is diffused into the reagent solution through the gas permeable membrane in the gas diffusion cell, and a change in the reagent solution is measured with a photometer. The liquid pump has a capacity capable of storing an amount of solution necessary for at least one analysis, and a necessary amount of liquid is sent by the operation of the piston in the pushing direction. A piston pump type pump is used in which the liquid in the flow path is sucked by retreating, and the flow path is opened and closed downstream of the gas diffusion cell in the sample solution flow chamber and / or the reagent flow path. An on-off valve is provided, and after each solution is fed into each of the chambers by operating the piston of each of the liquid feeding pumps in the pushing direction, the operation of both the liquid feeding pistons is stopped to stop the liquid feeding, and the sample solution is stopped. By closing the flow path downstream of the flow chamber and / or the reagent solution flow chamber, and then pressurizing the sample solution flow chamber and / or depressurizing the reagent solution flow chamber, the two chambers are closed. A gas diffusion flow injection analyzer characterized in that the gas diffusion can be performed by keeping the apparatus stationary for a certain period of time with a differential pressure applied therebetween. 4. The apparatus according to claim 3, further comprising a suction pump for reducing the pressure in the reagent solution flowing chamber, in addition to the reagent sending pump.
3. The gas diffusion flow injection analyzer according to item 1.