JPH0778497B2 - Background removal equipment - Google Patents

Description

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

<Prior Art> Generally, in order to analyze anions in a liquid to be measured, a separation column filled with an anion exchange resin having a low ion exchange capacity is used to dilute a basic solution (for example, sodium carbonate or sodium hydroxide). A certain amount of the liquid to be measured is carried by the mobile phase consisting of (1) and the like, and anions in the liquid to be measured are chromatographically separated for analysis. The anion in the liquid to be measured can be obtained by directly detecting the eluate from the separation column with a detector (for example, a conductivity detector) to obtain a chromatogram as the above analysis result. A suppressor column filled with an acid-type cation exchange resin is placed between the column and the mobile phase (eluate from the column) is passed through the suppressor column to conduct the mobile phase (for example, sodium hydroxide or sodium carbonate). By changing the counter ion of the anion in the liquid to be measured to a hydrogen ion while using a liquid with a low rate (for example, water or carbonic acid), the conductivity of the mobile phase is lowered and the S / N ratio is improved. The measurement of anions in the measurement liquid is performed. In this case, if a cation exchange membrane can be used in place of the suppressor column packed with an acid type cation exchange resin, anions can be continuously converted through the cation exchange membrane. It is very convenient to use the analyzer.

<Problems to be Solved by the Invention> However, as a conventional example of a suppressor using a cation exchange membrane, there is a suppressor including a cation exchange tube having a double-tube structure. This has a double tube structure in which a hollow cation 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 the hollow cation exchange tube, and the effluent flows counter-currently to the mobile phase flow on the outside of the cation exchange tube 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 a hollow cation exchange tube, the ion exchange efficiency is not so high and it is difficult to reduce the background 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.
Since the spherical substance (for example, an ion exchange resin) is filled in the three spaces formed by the ion exchange membrane and the spacer, there is a problem that the ion exchange membrane is deformed or damaged during the manufacturing and processing steps.

The present invention has been made in view of the drawbacks of the conventional examples, and an object thereof is an easily available sheet-shaped cation exchange membrane and spherical packing (for example, cation exchange resin, polymer beads, glass spheres). , Metal balls, etc.) and a weaving net (for example, a screen mesh used for sieving and made of stainless steel, nylon, polyethylene, polypropylene, fluororesin, etc.) to provide a background removal device having a simple structure (structure). is there.

<Means for Solving Problems> A feature of the present invention for solving the above problems is that the first to fifth sheets mounted on the anion analyzer for analyzing anions in the liquid to be measured. And the upper and lower sides thereof are sandwiched between the first and second substrates, and the mobile phase is caused to flow in the gap flow path of the third sheet sandwiched between the second and fourth sheets, and
And a background removing device for reducing the conductivity background of the object to be measured by causing a removing liquid to flow in the gap flow paths of the first and fifth sheets formed outside the fourth and fourth sheets. Sheet is a woven net having a long groove in the central portion and sealed with a rubber-like material on the periphery, the second and fourth sheets are cation exchange membranes, and the third sheet is filled with a spherical material. It is composed of a sheet having long grooves.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. First
The figure is a conceptual diagram showing in detail the principle of reduction (removal) of the conductivity background as described above. In this figure, among the three chambers C1 to C3 partitioned by two cation exchange membranes M, C2 through which the component to be measured passes is filled with a spherical substance R such as a cation exchange resin, The dead volume is decreasing. The chambers C1 and C3 through which the removing liquid passes are long grooves made of a woven net S formed in the center by sealing the periphery with a rubber-like substance, and have a small capacity and ion exchange without increasing the flow path resistance too much. It is designed to improve the efficiency of ion exchange through the membrane M. An eluent or a solution to be measured (for example, NaOH containing NaCl) eluted from a separation column containing a sample to be measured (for example, Cl-ion) flows into the room C2, and the eluent and a countercurrent direction flow to the chambers C1 and C3. A removing liquid (eg, H ₂ SO ₄ ) is flowing in the inside. In this state, the eluent from the separation column in chamber C2 and the solution to be measured (for example, Na containing NaCl)
Na ⁺ ions contained in OH) are ion-exchanged with H ⁺ ions contained in the removing liquid (for example, H ₂ SO ₄ ) in the chambers C1 and C3 through the cation exchange membrane M. At this time, the eluent from the separation column and the component to be measured (for example, Cl −) in the solution to be measured have the same electric charge as the ion exchange membrane M partitioning each chamber, and thus remain in the chamber C2 without being ion-exchanged. For this reason, room C2
The liquid that elutes from is a liquid (for example, H ₂ O) from which the conductivity background containing the component to be measured (for example, HCl for NaCl) whose counter ions have become H ⁺ type (for example, H ₂ O) has been removed. The liquids eluted from C3 and C3 are, for example, a Na ⁺ -type removal solution (for example, Na ₂ SO ₄ ) and an excess removal solution (for example, H ₂ ) when ion-exchanged with cations in the eluent or the solution to be measured.
It becomes a highly conductive liquid containing SO ₄ ). The weaving net S having a long groove in the central portion, which is sealed with a rubber-like material around the periphery thereof, is manufactured as follows. That is, a masking tape of a size that can be used as a flow channel is attached to the center of a screen mesh of a woven net (generally a twill weave) used for sieving, and liquid rubber (sealing agent or adhesive Then, the liquid rubber is cured. When the masking tape is peeled off after the rubber has hardened, the rubber does not penetrate into the masking tape portion, and this portion becomes a flow channel (removing liquid flow channel).

On the other hand, FIG. 2 is an exploded perspective view of the embodiment of the present invention.
FIG. 3 is an explanatory diagram of a configuration of a usage example of the embodiment of the present invention. Second
In the figure, 1 is a first substrate made of, for example, an acrylic plate, 1a
1 to 1a10 are through holes provided in the first substrate, 1b is through hole 1a1
Bolts inserted in, 1c is an inlet for eluent, 1d is a first inlet for removal liquid, 1e is an outlet for eluent, 1f is a first outlet for removal liquid, 2 is a peripheral A first sheet made of, for example, a nylon woven net, which is sealed with a rubber-like substance and provided with a groove 2a at the center, 3 is a second sheet made of a sheet-like cation exchange membrane, and 4 has a groove 4a at the center. For example, a third sheet made of rubber, 5 is a fourth sheet made of a sheet-shaped cation exchange membrane, and 6 is a groove in the central portion, which is surrounded by a rubber-like substance.
A fifth sheet made of, for example, a nylon woven net provided with 6a, a second substrate 7 made of, for example, an acrylic plate, 7a1 to 7a1
0 is a through hole provided in the second substrate, and 7c is a second removal liquid.
Inlet, 7d is second outlet for removing liquid, 8a1 is washer, 8
b1 is a nut that fits the screw part of the bolt 1b1. The third
In the groove 4a of the sheet, a spherical substance such as a cation exchange resin is embedded (filled).

The embodiment of the present invention having the above-described disassembled configuration is
After the fifth sheets 2 to 6 are laminated, the sheets 2 to 6 are sandwiched between the first and second substrates 1 and 7, and then the bolt 1b is inserted.
1 (and bolts 1b2 to 1b10 not shown) are passed through the through hole 1a1 (and 1a2 to 1a10) and the through hole 7a1 (and 7a2 to 7a10), and then the washer 8a1 (and washer 8a2 to 8a not shown).
10) is inserted, and finally bolts 1b1 (and 1b2-1b10)
Nut 8b1 (and nuts 8b2 to 8b1
By screwing 0), the assembly of the background removing device according to the embodiment of the present invention is completed. The background removing device thus assembled is used by being attached to the anion analyzer shown in FIG. That is, FIG. 3 is an explanatory view of the configuration of a usage example of the embodiment of the present invention.
In the figure, the separation column 12, the suppressor 13, and the detector 14 are housed 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 switching valve 11
First and second connection ports 11a, 11b → separation column 12 → introduction port 1c of the inner chamber 13b of the background removal device 13 → inner chamber 13b of the background removal device 13 → background removal device 1
The discharge port 1e of the inner chamber 13b of 3 flows into the waste liquid tank 9c through the detector 14, and when the pump 10b is driven, the removal liquid in the tank 9b becomes 1
Pump 10b → background removal device 1 at a flow rate of ml / min
First introduction port 1d of the outer chamber 13c of 3 → Background removal device 13
Outer chamber 13c of the first → outer chamber 13c of the background removal device 13
Outlet 1f → second of the outer chamber 13c of the background removal device 13
It flows into the waste liquid tank 9d through the inlet 7c → the outer chamber 13c of the background removing device 13 → the second outlet 7d of the outer chamber 13c of the background removing device 13. Therefore, the cations contained in the fluid flowing in the inner chamber 13b (groove 4a in FIG. 2) of the background removing device 13 are cation exchange membranes 13a (second in FIG. 2).
The conductivity is obtained by exchanging with cations contained in the fluid flowing in the outer chamber 13c (groove 2a and groove 6a in FIG. 2) of the background removing device 13 via the sheet 3 and the fourth sheet 5). Will be able to lower the background.

<Effects of the Invention> According to the embodiments of the present invention described in detail above, a sheet-shaped cation exchange membrane and a spherical substance (for example, cation exchange resin, polymer beads, glass spheres, metal spheres) that are easily available are used. Etc.) and the surroundings are sealed with a rubber-like substance and have a long groove in the center (for example, a screen mesh used for sieving, the material is stainless steel, nylon, polyethylene, polypropylene, fluororesin, etc.), and the peak shape in the chromatogram. A background removal device with a small dead volume and a simple structure (structure) that does not impair the performance is realized. Further, the space (specifically, the long grooves 2a and 6a) formed by the cation exchange membrane and the spacers (first to fifth sheets 2 to 6) is, for example, a nylon woven mesh, and therefore the woven mesh is used. Since it backs up the cation exchange membrane to increase the pressure resistance of the flow system through which the eluent flows, it is possible to fill the space (specifically, long groove 4a) in which the liquid to be measured flows with a spherical substance at high pressure and high density. There is also an advantage that the exchange membrane is not deformed or damaged. Further, since the woven net is used, the efficiency of contact between the ion exchange membrane and the removing liquid can be increased despite the small space through which the removing liquid flows. As a manufacturing problem, it is not necessary to fill all three spaces (specifically long grooves 2a, 4a, 6a) formed by the cation exchange membrane and the spacer, and one space (specifically long groove 4a). ), It is easy to manufacture. Further, the filling material filled in the space (specifically, the long groove 4a) in which the liquid to be measured flows is
Even polymer beads, glass spheres, or metal spheres are effective because similar effects appear.

[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, 2-6 ... Sheet, 2a, 4a, 6a ... Groove, 9a, 9d ... Bath, 10a, 10b ... Pump, 11 ... Switching valve, 12 ... Separation column, 13 …… Suppressor, 14 …… Detector, 15 …… Constant bath

Claims (2)

[Claims] 1. An anion analyzer for analyzing anions in a liquid to be measured, the first to fifth sheets being laminated, and the upper and lower sides of which are sandwiched by a first and a second substrate. The mobile phase is caused to flow in the gap flow passages of the third sheet sandwiched between the second and fourth sheets, and the removing liquid is passed through the gap flow passages of the first and fifth sheets formed outside the second and fourth sheets. In the background removing device that reduces the conductivity background of the liquid to be measured by flowing, the first and fifth sheets are woven nets having a long groove in the center sealed with a rubber-like substance on the periphery, The second and fourth sheets are cation exchange membranes, and the third sheet is a sheet having long grooves filled with a spherical substance, wherein the background removing device is characterized. 2. The background removing device according to claim 1, wherein the third sheet is filled with cation exchange resin, polymer beads, glass spheres, and metal spheres.