JP2525657B2 - Background removal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention is mounted on a cation analyzer for analyzing cations in a liquid to be measured, and the conductivity of the eluate from the separation column or the sample solution itself is backed up. The present invention relates to a background removal device that reduces the ground.

<Prior art> Generally, in order to analyze cations in a liquid to be measured, a separation column filled with a cation exchange resin having a low ion exchange capacity is used with a dilute acid solution (for example, nitric acid or sulfuric acid). A certain amount of the liquid to be measured is carried by the mobile phase, and the cations in the liquid to be measured are chromatographically separated for analysis. For the detection of cations in the liquid to be measured, the eluate from the separation column can be directly detected by a detector (for example, a conductivity detector) to obtain a chromatogram as the above analysis result. A suppressor column packed with an OH ^- type anion exchange resin is placed between the column and the mobile phase (eluate from the column) is passed through the suppressor column to convert the acid to water and the anion in the solution to be measured. By changing the counter ion of the ion to a hydroxide ion, the conductivity of the mobile phase is lowered to improve the S / N ratio, and the anion in the solution to be measured is measured. In this case, if a suppressor column filled with an acid-type anion exchange resin can be replaced with one using an anion exchange membrane, it can be continuously converted into water through the anion exchange membrane, and thus anion analysis It is very convenient to use the device.

<Problems to be Solved by the Invention> However, as a conventional example of a suppressor using an anion exchange membrane, there is a suppressor including an anion exchange tube having a double-tube structure. This has a double tube structure in which a hollow anion exchange tube having an outer diameter smaller than the inner diameter of these tubes is put in stainless steel or Teflon tube. The eluate from the column flows through a hollow anion exchange tube, and the remover flows outside the column in countercurrent to the mobile phase flow so that the background can be continuously removed. Has become. Further, as an example of using a sheet-shaped ion exchange membrane, two ion exchange membranes and three spacers having long grooves filled with a spherical filler (for example, an ion exchange resin) are laminated to form the above double tube structure. There are some that have the same effect as the suppressor.

However, since the suppressor having the double-tube structure uses the hollow anion exchange tube, the ion exchange efficiency is not so high and it is difficult to reduce the bag ground with high efficiency. Therefore, in order to obtain a sufficient suppressive effect, a considerable length is required, and as a result, the internal volume increases, an excessive analysis time is consumed, and there is a problem that the components separated in the separation column spread. . As a measure for improving these problems, it is conceivable to use an ion exchange tube having a small inner diameter or an ion exchange tube having high ion exchange efficiency, but such a tube is very difficult to obtain. In addition, there is a problem that production and processing are not so easy. Further, a packed ion exchange membrane suppressor using an ion exchange membrane improves the drawbacks of the double-tube structure suppressor described above. However, a spherical substance (for example, an ion) is formed in the three spaces formed by the ion exchange membrane and the spacer. Since it is filled with exchange resin, there is a problem that the ion exchange membrane is deformed and damaged during the manufacturing and processing steps.

The present invention has been made in view of the drawbacks of the conventional example, and an object thereof is to easily obtain a sheet-like anion exchange membrane and spherical packing (for example, anion exchange resin, polymer beads, glass spheres). It is to provide a background removal device having a simple configuration (structure) using metal balls or the like.

<Means for Solving Problems> The feature of the present invention for solving the above problems is that the conductivity background of the measured liquid is mounted on the anion analyzer for analyzing anions in the measured liquid. In a background removal device for reducing the amount of the above, first and second sheets composed of anion exchange membranes whose front and back surfaces are sealed with a sticky rubber-like substance having a long groove in the central part are laminated and the upper and lower parts thereof are first and second. The second substrate is sandwiched, and the mobile phase is caused to flow in the interstitial channels formed inside the first and second sheets, and the removal liquid is applied to the interstitial channels formed outside the first and second sheets. There is to shed.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. Fig. 1 shows reduction (removal) of conductivity background as described above.
3 is a conceptual diagram of the present invention showing in detail the principle of FIG. In this figure, among the three chambers partitioned by the two anion exchange membranes M, C2 through which the component to be measured passes is filled with a spherical substance R such as anion exchange resin, and the dead volume is It's getting less. In addition, the chamber C1 through which the removal liquid passes and
C3 is a long groove, which has a small capacity and improves the ion exchange efficiency through the ion exchange membrane M without increasing the flow path resistance too much. The room C2 measured sample (e.g., Na ⁺ ion) eluent or the measured solution eluted from the separation column (e.g., HNO ₃ containing NaNO ₃₎ HNO ₃ contained in ^- ions, room Anion exchange membrane M with OH ^- ions contained in the removal solution (eg NaOH) in C1 and C3
Ion exchange through. At this time, the eluent from the separation column and the component to be measured (for example, Na ⁺ ) in the solution to be measured have the same charge as the ion exchange membrane M partitioning each room, so that they are not ion-exchanged and enter the room C ₂ . Remain. For this reason, room C ₂
Liquid eluting from, are ion-exchanged counterion OH ^-
The liquid with the background of the conductivity removed (eg H ₂ O) containing the measured component (eg NaOH for NaNO ₃ )
Thus, the liquids eluted from the chambers C1 and C3 are, for example, NO ₃ ⁻ type removal liquid (eg NaNO ₃ ) which is ion-exchanged with anions in the eluent or the solution to be measured and an excess removal liquid (eg N 3
It becomes a highly conductive liquid containing aOH).

On the other hand, FIG. 2 is an exploded perspective view of an embodiment of the present invention, and FIG. 3 is an explanatory view of a configuration of a use example of the embodiment of the present invention.
In FIG. 2, reference numeral 1 is a first substrate made of, for example, an acrylic plate, 1a1 to 1a12 are through holes provided in the first substrate, 1b is a bolt inserted into the through hole 1a1, and 2a is a first introduction for a removing liquid. Port, 2b is an inlet for an eluent, 2c is a second inlet for a remover, 2d is a second outlet for a remover, 2e is an outlet for an eluent, and 2f is a first outlet for a remover. The outlet port 3 is made of a sticky rubber-like substance and is a sheet-like anion exchange membrane having a long groove 4a in the center of the front side and a long groove 4b in the center of the back side. Second sheet made of a sheet-shaped anion-exchange membrane having a long groove 6a in the central portion on the front side and a long groove 4b in the central portion on the back side, which is made of a rubbery substance having a hydrophilic property, 7
Is a second substrate made of, for example, an acrylic plate, and 7a1 to 7a12 are second substrates.
Through hole provided on the board, 8a1 is a washer, 8b1 is a bolt
It is a nut that fits the screw part of 1b1. A spherical substance, for example, an anion exchange resin is embedded (filled) in the gap flow path formed by the groove 4b of the first sheet 3 and the groove 6a of the second sheet 5.

In the embodiment of the present invention shown in the exploded configuration diagram as described above, the first and second sheets 3 and 5 are laminated and then the sheets 3 and 5 are sandwiched between the first and second substrates 1 and 7. Then bolt
1b1 (and bolts 1b2-1b12 not shown) are through holes 1a1
(And 1a2-1a12) and through hole 7a1 (and 7a2-7a12), and then washer 8a1 (and washer 8a2 not shown).
~ 8a12) and finally bolts 1b1 (and 1b2-1b1)
2) Thread the nut 8b1 (and nuts 8b2-8
By assembling b12), the assembly of the background removing device according to the embodiment of the present invention is completed. The background removing device assembled in this way is used by being attached to a cation analyzer as shown in FIG.
That is, FIG. 3 is a diagram for explaining the configuration of a usage example of the embodiment of the present invention, in which a separation column 12, a suppressor 13, and a detector 14 are shown.
Is stored in a constant temperature bath 15 and kept at a constant temperature (for example, 45 ° C.). When the pump 10a is driven, the eluent in the tank 9a flows at a flow rate of 1 ml / min, for example, the pump 10a → the first and second connection ports 11a and 11b of the switching valve 11 → the separation column 12 →
Inlet port 1c of the inner chamber 13b of the background removal device 13 → inner chamber 13b of the background removal device 13 → outlet port 1e of the inner chamber 13b of the background removal device 13 → waste liquid tank 9c through the detector 14
When the pump 10b is driven, the removal liquid in the tank 9b
For example, at a flow rate of 1 ml / min, the pump 10b → the first inlet 1d of the outer chamber 13c of the background removing device 13 → the outer chamber 13c of the background removing device 13 → the outer chamber 1 of the background removing device 13
First outlet 1f of 3c → Outer chamber 13 of background removal device 13
Second introduction port 7c of c → outer chamber 13c of background removal device 13
→ The second outlet 7d of the outer chamber 13c of the background removal device 13
And then to the waste liquid tank 9d. Therefore, the anions contained in the liquid flowing in the inner chamber 13b (the gap flow path formed by the grooves 4b and 6b in FIG. 2) of the background removal device 13 are anion exchange membrane 13a (see FIG. 2). The outer chamber 13c of the background removing device 13 through the first sheet 3 and the second sheet 5) of
It becomes possible to exchange with anions contained in the liquid flowing in the (gap passage formed by the groove 4a and the groove 6a in FIG. 2) and ultimately reduce the background of the conductivity.

<Effects of the Invention> According to the embodiments of the present invention as described in detail above,
Sheet-shaped anion exchange membrane and spherical material that are easily available (for example, anion exchange resin, polymer beads, glass spheres,
By using metal spheres or the like), a background removal device having a very small dead volume and a simple structure (structure) that does not impair the peak shape in the chromatogram is realized.

That is, the structure is formed (constituted) of only an anion exchange membrane and an adhesive rubber-like substance for forming a flow path on the ion exchange membrane, so that the dead volume is reduced due to an increase in the number of parts. Also, since it is composed of only four parts, the two bases 1 and 7 and the two sheets 3 and 5, the flow path configuration is simple and the leakage of the solution is small. In other words, since the number of sheets is small, it is possible to avoid the leakage of the eluent and the leakage of the removed liquid due to the poor adhesion between the parts, compared to the case where a large number of sheets are stacked. Further, since the number of sheets is small, there is an advantage that the tightening pressure for stacking is small and uniform.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing in detail the principle of conductivity background removal, FIG. 2 is an exploded perspective view of an embodiment of the present invention, and FIG.
The figure is an explanatory view of a configuration of a usage example of the embodiment of the present invention. 1,7 …… Substrate, 2,5 …… Sheet, 4a, 4b, 6a, 6b …… Groove, 10
a, 10b …… Pump, 11 …… Switching valve, 12 …… Separation column, 13 …… Suppressor, 14 …… Detector, 15 …… Constant temperature bath

Claims (4)

(57) [Claims] 1. A background removing device for reducing the conductivity background of a liquid to be measured, which is attached to a cation analyzer for analyzing cations in a liquid to be measured, and is an adhesive rubber-like material having a long groove in the center thereof. The first and second sheets made of an anion exchange membrane, the front and back of which are sealed with a substance, are laminated, and the upper and lower sides of the first and second substrates are sandwiched and formed inside the first and second sheets. The background removing device is characterized in that the mobile phase is caused to flow through the interstitial flow channel and the removal liquid is caused to flow through the interstitial flow channel formed on the outer periphery of the first and second sheets. 2. The background according to claim 1, wherein the first and second sheets used are anion exchange membranes whose front and back are sealed with an adhesive rubber-like substance having a long groove in the central portion. Removal device. 3. A viscous rubber-like substance formed on the ion exchange membrane and having a long groove in the central portion, cures liquid rubber such as an adhesive directly on the ion exchange membrane and forms the long groove in the central portion. The background removing device according to claim 1, wherein 4. The bag according to claim 1, wherein the gap flow path surrounded by the first and second sheets is filled with anion exchange resin, polymer beads, glass spheres, and metal spheres. Ground removal device.