JPH04301560A - Background removing appartus for cation - Google Patents

Abstract

PURPOSE:To obtain a cation background removing apparatus which is excellent in durability and high ion exchange capability having a simple structure by using an anion exchanging film, a spherical filling material and a woven net sheet which are easily available. CONSTITUTION:First to third sheets 2, 3, 4 are laminated and the laminated assembly is interposed between a first substrate 1 having a long groove 1a on a surface in contact with the first sheet 2 and a second substrate 5 having a long groove 5a on a surface in contact with the third sheet 4. A mobile phase is made flow into a slit path 3a of the second sheet 3 interposed between the first and third sheets 2,4 and also removing solution is made flow into a slit path 1a interposed between the first sheet 2 and the first substrate 1 formed outside the first sheet 2 and into a slit path 5a interposed between the first sheet 2 and the second substrate 5 formed outside the first and third sheets 2, 4.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a cation analyzer that is installed in a cation analyzer for analyzing cations in a liquid to be measured, and is used to reduce the conductivity background of the eluate from a separation column or the sample solution itself. The present invention relates to a background removal device.

0002

[Prior Art] Generally, in order to analyze cations in a liquid to be measured, a separation column packed with a cation exchange resin with a low exchange capacity is filled with a dilute acidic solution (such as nitric acid or sulfuric acid). A fixed amount of the liquid to be measured is transported in the phase, and the cations in the liquid to be measured are chromatographically separated for analysis. Further, detection of cations in the liquid to be measured can be performed by directly detecting the eluate from the separation column with a detector (eg, a conductivity detector) and obtaining a chromatogram as an analysis result.

However, there is an OH-
A suppressor using a type anion exchange membrane is placed, and the mobile phase (eluate from the column) is passed through the suppressor to convert the mobile phase (e.g. nitric acid, sulfuric acid, etc.) to a liquid with low conductivity (e.g. water, etc.). It is also carried out by changing the counter ions of the cations in the liquid to be measured into hydroxide ions, which are then detected by a detector to obtain a chromatogram as the analysis result. That is, by doing so, cations in the liquid to be measured can be measured while lowering the conductivity of the mobile phase and improving the S/N ratio.

[0004] In this case, the suppressor is usually made of an anion exchange tube with a double tube structure. This has a double tube structure in which a hollow anion exchange tube with an outer diameter smaller than the inner diameter of these tubes is placed inside a stainless steel or Teflon tube. In addition, the eluate from the column flows through a hollow anion exchange tube, and the removal solution flows outside the tube in countercurrent to the flow of the mobile phase, allowing background to be continuously removed. It looks like this.

However, since the above suppressor uses a hollow anion exchange tube, the ion exchange efficiency is not very high and it is difficult to reduce the background with high efficiency. Therefore, in order to obtain a sufficient suppressing effect, a considerable length is required, resulting in an increase in internal volume, resulting in extra analysis time and the spread of the components separated in the separation column. Possible solutions to this problem include using ion exchange tubes with a small inner diameter or ion exchange tubes with high ion exchange efficiency, but such tubes are extremely difficult to obtain, and There is also the problem that manufacturing and processing are not very easy.

[0006] In addition, as an example of using a sheet-like ion exchange membrane that improves the drawbacks of the above-mentioned double tube structure suppressor, there is a structure in which two anion exchange membranes and a spherical filler (for example, an anion exchange resin) are used. A stack of three spacers each having a filled long groove is known. However, the spherical material (for example, anion exchange resin) filled in the groove through which the liquid to be measured flows is pushed by the liquid to be measured and is biased toward one end of the groove.
This method has the drawbacks of damaging the anion exchange membrane and reducing the ion exchange capacity.

[Problem to be solved by the invention]

The present invention was made in view of the drawbacks of the conventional examples, and its purpose is to use an easily available sheet-shaped anion exchange membrane, spherical packing, and woven net-like sheet, and to improve durability. An object of the present invention is to provide a background removing device for cations having a simple structure and excellent performance and high ion exchange capacity.

[0008]

[Means for Solving the Problems] <Means for Solving the Problems> The feature of the present invention that solves the above-mentioned problems is that it is installed in a cation analyzer that analyzes cations in a liquid to be measured. A cation background removal device for reducing the conductivity background of a liquid to be measured includes a first sheet made of an anion exchange membrane and a second sheet having long grooves filled with a woven mesh impregnated with a spherical substance. and a third sheet made of an anion exchange membrane, the first to third sheets are laminated, and the first substrate has a long groove on its top and bottom surfaces in contact with the first sheet; A second substrate having a long groove on the surface in contact with the third sheet is used to narrowly bond the first and third sheets.
The mobile phase is caused to flow through the gap flow path of the second sheet sandwiched between the sheets, and the gap flow path formed outside the first sheet sandwiched between the first sheet and the first substrate and the third sheet. The removal liquid is made to flow through a gap flow path formed on the outside of the third sheet sandwiched between the second substrate and the third sheet.

[0009]

[Operation] The present invention operates as follows. That is, FIG. 1 is a conceptual diagram showing in detail the principle of conductivity background removal related to the present invention in order to explain the effect of the present invention.
2 and C3 are filled with a spherical filler R such as an anion exchange resin, and the waste volume is reduced. In addition, an eluent containing a component to be measured (e.g., Na+ ion) eluted from the separation column and a solution to be measured (e.g., HNO3 containing NaNO3) flow in the room C2, and a countercurrent flow with the eluent flows in the rooms C1 and C3. A removal liquid (for example, NaOH) is flowing in the direction.

In this state, the eluent from the separation column in the room C2 or the solution to be measured (for example, containing NaNO3) is
The NO3 - ions contained in the HNO3 ) are ion-exchanged with the OH - ions contained in the removal liquid (for example, NaOH) in the chambers C1 and C3 via the anion exchange membrane M. At this time, the eluate from the separation column and the component to be measured (for example, Na+ ion) in the solution to be measured have the same charge as the ion exchange membrane M that partitions each chamber, so they remain in the chamber C2 without being ion-exchanged. For this reason, room C2
The liquid eluted from is ion-exchanged and the counterion becomes O
A liquid (e.g. H
2 O), and the liquid eluted from chambers C1 and C3 is a removal liquid (e.g., NaN
The result is a highly conductive liquid containing O3) and excess removal liquid (for example, NaOH).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. FIG. 2 is an exploded perspective view of the embodiment of the present invention. In this figure, 1 is a first substrate made of, for example, an acrylic plate, 1a is a groove provided in the center, 1a1 to 1a10 are through holes provided in the first substrate, and 1b1 is a through hole 1a1.
1c is the inlet for the eluent, 1d is the first inlet for the removal liquid, 1e is the outlet for the eluent, 1f
2 is a first sheet made of a sheet-shaped anion exchange membrane; 3 is a second sheet made of rubber, for example, and has a groove 3a in the center; 4 is a sheet-shaped anion exchange membrane; A third sheet made of ion exchange membrane,

5 is a second substrate made of, for example, an acrylic plate;
a is a groove provided in the center, 5a1 to 5a10 are through holes provided in the second substrate 5, 5c is a second inlet for the removal liquid, 5d is a second outlet for the removal liquid, 6a1 is a washer,
6b1 is a nut that fits with the threaded portion of bolt 1b1. Note that the grooves 1a of the first substrate, the grooves 2a of the second sheet, and the grooves 5a of the second substrate are all filled with a spherical filler or a woven net-like sheet, such as an anion exchange resin.

By the way, a woven mesh sheet 3b filled with an anion exchange resin is produced. That is, first, polyvinyl alcohol is dissolved in warm water to a concentration of about 2 to 5%, and a small amount of an anion exchange resin of about 100 to 200 mesh is uniformly dispersed in 10 ml of this polyvinyl alcohol aqueous solution. Next, a predetermined amount of a polyvinyl alcohol aqueous solution in which an anion exchange resin is dispersed is placed on the woven net-like sheet.

[0014] Thereafter, this sheet is held in air, impregnated with an aqueous polyvinyl alcohol solution in which an anion exchange resin is dispersed, and then air-dried. In this way, a woven mesh sheet impregnated with an aqueous polyvinyl alcohol solution in which an anion exchange resin is dispersed is assembled as a background removing device as shown in FIG. After the assembly is completed, add 0.2ml to 0.0ml of water from the eluent inlet.
．． The polyvinyl alcohol is removed by flowing the solution at a flow rate of about 5 ml for 12 hours or more.

On the other hand, in the embodiment of the present invention which has an exploded configuration as shown in FIG. 1 and 5, and then bolt 1b1 (and bolts 1b2 to 1b10 (not shown)) are inserted into through hole 1a1 (and 1a2
~1a10) and through hole 5a1 (and 5a2 ~5a1
0), a washer 6a1 (and washers 6a2 to 6a10, not shown) is inserted, and finally a nut 6b1 (and nuts 6b2 to 6b1, not shown) is inserted into the threaded portion of the bolt 1b1 (and 1b2 to 1b10).
0), the assembly of the cation background removing device according to the embodiment of the present invention is completed.

The cation background removing device thus assembled is used by being attached to a cation analyzer as shown in FIG. That is, FIG. 3 is an explanatory diagram of the configuration of an example of use of the embodiment of the present invention, in which the separation column 10, suppressor 11, and detector 12 are housed in a constant temperature bath 13 and kept at a constant temperature (for example, 45° C.). It is maintained.

Furthermore, when the pump 8a is driven, the eluent in the tank 7a flows through the pump 8a at a flow rate of, for example, 1 ml/min.
a→First and second connection ports 9a, 9b of switching valve 9→
Separation column 10 → background removal device for cations 1
Inlet port 1c of inner chamber 13b of No. 3 → Inner chamber 11b of background remover 11 for cations → Outlet port 1e of inner chamber 11b of background remover 11 for cations → Detector 12
When the pump 7b is driven, the removed liquid in the tank 7b flows at a rate of, for example, 1 ml/min. With a flow rate of
Pump 7b→first inlet 1d of outer chamber 11c of background remover 11 for cations→outer chamber 11c of background remover 11 for cations→first of outer chamber 11c of background remover 11 for cations Outlet 1f → second inlet 5c of outer chamber 11c of background remover 11 for cations → outer chamber 11c of background remover 11 for cations → outer chamber 11c of background remover 11 for cations The liquid flows to the waste liquid tank 7d via the second outlet 5d.

Therefore, the anions contained in the liquid flowing in the inner chamber 11b (groove 3a in FIG. 2) of the background removing device 11 for cations are removed by the anion exchange membrane 11a (groove 1 in FIG. 2). The anions contained in the liquid flowing in the outer chamber 11c (grooves 1a and 5a in FIG. 2) of the background removing device 11 for cations are exchanged through This makes it possible to reduce the background conductivity in cation analysis. Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways.

[0019]

Effects of the Invention According to the embodiments of the present invention as described in detail above, an easily available sheet-shaped anion exchange membrane,
By using a spherical filler, a woven net-like sheet, a water-soluble glue, etc., a cation background removal device with a simple structure with a small dead volume and excellent durability and ion exchange ability is realized. Also, in Figure 2, the second
A woven mesh sheet 3b impregnated with an anion exchange resin, which is filled in the grooves 3a of the sheet 3, is an anion exchange membrane 2.
, 4 to increase the withstand pressure of the flow system through which the eluent flows, and compared to the conventional suppressor in which the anion exchange resin is directly filled in the groove 3a of the second sheet 3, the anion exchange resin filled in the suppressor is There is also the advantage that the resin hardly moves within the grooves 3a, thereby significantly improving ion exchange ability and durability.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing in detail the principle of conductivity background removal.

FIG. 2 is an exploded perspective view of the embodiment of the present invention.

FIG. 3 is an explanatory diagram of an example of use of the embodiment of the present invention. 1 First substrates 1a, 5a Grooves 1a1 to 1a10 Through holes 1b1 Bolts 1c, 1d Inlets 1e, 1f Outlets 2 First sheet 3 made of a sheet-shaped anion exchange membrane
Second sheet 4 having a groove in the center Third sheet 5 made of a sheet-shaped anion exchange membrane Second substrate 5a1 to 5a10 Through holes 5c, 5d Inlet 6a1 Washer 6b1 Nuts 7a to 7d Tanks 8a, 8b Pump 9 Selector valve 10 Separation column 11 Suppressor 12 Detector 13 Constant temperature bath

Claims (2)

[Claims] 1. A cation background removal device that is attached to a cation analyzer for analyzing cations in a liquid to be measured and reduces the conductivity background of the liquid to be measured, wherein a first a second sheet having long grooves filled with a woven net impregnated with a spherical substance, and a third sheet made of an anion exchange membrane, and the first to third sheets are laminated. The top and bottom of the substrate are sandwiched between a first substrate having a long groove on the surface in contact with the first sheet and a second substrate having a long groove on the surface in contact with the third sheet, and the first and third sheets are bonded to each other. The mobile phase is caused to flow through the gap channel of the sandwiched second sheet, and the gap channel formed between the first sheet and the first substrate and outside the first sheet, and between the first sheet and the first substrate. A background removal device for cations, characterized in that a removal liquid is caused to flow through a gap flow path sandwiched between two substrates and formed on the outside of the first and third sheets. 2. The long grooves of the second sheet are filled with anion exchange resin, polymer beads, glass spheres, or metal spheres dispersed in a water-soluble glue such as polyvinyl alcohol or starch. 2. The background removing device for cations according to claim 1, wherein the sizing agent is removed by impregnating it into a woven net and then dissolving the sizing agent in water.