JP2811794B2 - Background removal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> 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. The present invention relates to a background removing device for reducing ground.

<Conventional technology> Generally, in order to analyze cations in a liquid to be measured, a separation column packed with a cation exchange resin having a low exchange capacity is used.
A predetermined amount of the liquid to be measured is transported by a mobile phase composed of a dilute acidic solution (for example, nitric acid or sulfuric acid), and cations in the liquid to be measured are separated by chromatography to perform analysis.

The cations in the liquid to be measured can be detected by directly detecting the eluate from the separation column with a detector (for example, a conductivity detector) and obtaining a chromatogram as an analysis result. However, between the separation column and the detector OH
^- Place the suppressor column filled with anion exchange resin type, low liquid conductivity of the mobile phase (eg nitric or sulfuric acid) by passing the (eluate from the column) the suppressor column to the mobile phase (e.g. Water) and changing the counter ion of the cation in the liquid to be measured to hydroxide ion, and then detecting it with a detector to obtain a chromatogram as an analysis result. That is, by doing so, the cation in the liquid to be measured is measured while lowering the conductivity of the mobile phase and improving the S / N ratio. In this case, if a column using an anion exchange membrane can be used instead of the suppressor column packed with an OH ^- type anion exchange resin, water can be continuously converted through the anion exchange membrane, so that the cation This is extremely convenient for using the analyzer. However, as a conventional example of a suppressor using an anion exchange membrane, a suppressor including an anion exchange tube having a double tube structure is known. 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 placed in a stainless steel or Teflon tube. The eluate from the column flows through a hollow anion exchange tube,
The removing liquid flows countercurrent to the flow of the mobile phase on the outside thereof, so that the background can be continuously removed.

<Problems to be Solved by the Invention> However, since the suppressor uses a hollow anion 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 suppression effect, a considerable length is required, and as a result, there is a problem that the internal volume increases, extra analysis time is consumed, and the components separated in the separation column are spread. . To remedy these problems, it is conceivable to use an ion exchange tube with a small inner diameter or to use an ion exchange tube with a high ion exchange efficiency. However, such a tube is very difficult to obtain. However, there is also a problem that manufacturing and processing are not so easy. Further, as an example of using a sheet-like ion exchange membrane in which the above-mentioned drawback of the double tube structure suppressor is improved, two ion exchange membranes and a long groove filled with a spherical packing (for example, ion exchange resin) are used. There are three types of spacers, such as a laminate of three spacers, and a laminate of ion exchange membranes sealed with an adhesive rubber-like substance having a long groove in the center, but many sheets are laminated,
The liquid leaks easily to process the ion exchange membrane,
There are problems that the production is not easy and the ion exchange membrane is easily damaged.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to provide a sheet-like anion exchange membrane which is easily available, a spherical packing made of cation exchange resin polymer beads, and nylon. It is an object of the present invention to provide a simple background removing device using a woven net-like sheet.

<Means for Solving the Problems> In order to achieve such an object, the present invention relates to a counter ion of a cation separated from a liquid to be measured in which a cation is separated by a separation column packed with a cation exchanger. A background sheet removing device for exchanging the solution with hydroxyl ions with a removing solution to lower the background of the solution to be measured, comprising: a second sheet having a long groove through which the solution to be measured separated from the cation flows; A substrate comprising a granular anion exchange resin filled in a long groove of a sheet, a first sheet and a third sheet sandwiching the second sheet from both sides, and a long groove through which the removing liquid flows; A first substrate provided with the liquid to be measured flowing through the long groove of the second sheet via the first sheet and the removing liquid, and a substrate having a long groove through which the removing liquid flows. And a second substrate provided so that the liquid to be measured flowing in the long groove of the second sheet via the third sheet and the removing liquid are in contact with each other.

Further, the long groove of at least one of the first substrate and the second substrate is filled with an anion exchange resin, polymer beads, glass spheres, metal spheres, or a woven mesh sheet.

<Operation> The present invention operates as follows. That is, FIG. 1 is a conceptual diagram showing in detail the principle of the removal of the conductivity background according to the present invention in order to explain the operation of the present invention, and three chambers C1, partitioned by two anion exchange membranes M, C2 and C3 are filled with a spherical filler R such as an anion exchange resin, so that the waste volume is reduced. In the room C2, an eluent eluted from a separation column containing a sample to be measured (for example, Na ⁺ ion) or a solution to be measured (for example, H containing NaNO _3).
NO ₃ ) flows, and a removing solution (for example, NaOH) flows in the chambers C1 and C3 in a countercurrent direction to the eluent. In this state, room C2
The eluent from the separation column inside the column or the solution to be measured (for example, NaNO
₃ is included in the HNO ₃₎ containing and NO ₃ ^- ions, room C1, C
The ion exchange is performed through the anion exchange membrane M with OH ^- ions contained in the removing solution (for example, NaOH) in 3. At this time, the eluent 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 room, and thus remain in the room C2 without ion exchange.
Therefore, the liquid eluting from the room C2 is ion exchanged with the counterion OH ^- measured component became type (e.g. NaOH)
The liquid having conductivity removed from the background (eg, H ₂ O), and the liquid eluted from the chambers C1 and C3 are ion-exchanged with an eluent and anions in the solution to be measured, for example, NO 2
It becomes a highly conductive liquid containing a ₃ ^- type removal solution (eg, NaNO ₃ ) and an excess removal solution (eg, NaOH).

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is an exploded perspective view of the embodiment of the present invention. In this drawing, 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, 1b1 is a bolt inserted into the through hole 1a1, 1c Is an inlet for the eluent, 1d is a first inlet for the removing solution, 1e is an outlet for the eluent, 1f is a first outlet for the removing solution, and 2 is a sheet-like anion exchange membrane. The first sheet 3 has a groove 3a at the center.
Is provided, for example, a second sheet made of rubber, 4 is a third sheet made of a sheet-like anion exchange membrane, 5 is a second substrate made of, for example, an acrylic plate, 5a is a groove provided in the center, 5a1-5
a10 is a through hole provided in the second substrate, 5c is a second inlet for the removing liquid, 5d is a second outlet for the removing liquid, 6a1 is a washer, and 6b1 is a nut that fits with the threaded portion of the bolt 1b1. . still,
Groove 1a of the first substrate, groove 3a of the second sheet, and groove of the second substrate
5a is filled with a spherical packing or a woven net-like sheet such as an anion exchange resin.

In the embodiment of the present invention having the above-described disassembled configuration, the first to third sheets 2 to 4 are stacked and then stacked.
4 is sandwiched between the first and second substrates 1 and 5, and then the bolt 1b1 (and the bolts 1b2 to 1b10, not shown) is inserted into the through hole 1a1.
(And 1a2 to 1a10) and the through hole 5a1 (and 5a2 to 5a10), and then the washer 6a1 (and the washer 6a2 (not shown)).
~ 6a10) is inserted, and finally bolt 1b1 (and 1b2 ~ 1b1)
The nut 6b1 (and nuts 6b2 to 6 (not shown))
By screwing b10), the assembly of the background removing device according to the embodiment of the present invention is completed.

The background removing device assembled in this manner is used by being attached to a cation analyzer as 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 drawing, the separation column 12, the suppressor 13, and the detector 14 are housed in a thermostat 15 and have a constant temperature (for example,
45 ° C). When the pump 10a is driven, the eluent in the tank 9a is pumped at a flow rate of, for example, 1 ml / min.
→ The first and second connection ports 11a and 11b of the switching valve 11 → the separation column 12 → the inlet port 1c of the inner chamber 13b of the background removing device 13 → the inner chamber 13b of the background removing device 13 → the background removing device 13 Flows through the outlet 1e of the inner chamber 13b to the waste liquid tank 9c via the detector 14, and when the pump 10b is driven, the removing liquid in the tank 9b is pumped at a flow rate of, for example, 1 ml / min. The first inlet 1d of the outer chamber 13c → the outer chamber 13c of the background remover 13 → the first outlet 1f of the outer chamber 13c of the background remover 13 → the second inlet of the outer chamber 13c of the background remover 13 The outlet 7c → the outer chamber 13c of the background remover 13 → the second outlet 7d of the outer chamber 13c of the background remover 13 flows to the waste liquid tank 9d. For this reason, the anions contained in the liquid flowing in the inner chamber 13b (the groove 4a in FIG. 1) of the background removing device 13 are removed by the anion exchange membrane.
13a (the second sheet 3 and the fourth sheet 5 in FIG. 1) and the outer chamber 13c of the background removing device 13 (the groove 2a in FIG. 1).
And exchange with the anions contained in the liquid flowing in the groove 6a), thereby ultimately lowering the background of conductivity.

<Effect of the Invention> As described above in detail, according to the embodiment of the present invention,
Easy to obtain sheet anion exchange membrane and spherical packing (for example, anion exchange resin, polymer beads, glass spheres, metal spheres, etc.) and woven mesh sheet (for example, screen mesh used for sieve etc.) Is stainless steel,
(Nylon, polyethylene, polypropylene, fluororesin, etc.), and a background removing device having a simple configuration with a small dead volume without impairing the peak shape in the chromatogram is realized. A space (specifically, the long grooves 1a, 3a, 5a) formed by the anion exchange membrane and the first to third sheets 2 to 4 (so-called spacers) is filled with a filler such as an anion exchange resin. Since the anion exchange resin is filled, there is also an advantage that the anion exchange resin backs up the anion exchange membrane and increases the pressure resistance of the flow system through which the eluent flows. Further, the same applies to the case where the filler filled in the space formed by the anion exchange membrane and the spacer (specifically, the long grooves 1a, 3a, 5a) is a polymer bead, a glass ball, a metal ball, or a woven mesh sheet. The effect is effective.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing in detail the principle of removing a conductivity background, FIG. 2 is an exploded perspective view of an embodiment of the present invention, and FIG.
FIG. 7 is an explanatory diagram of a configuration of a usage example of the embodiment of the present invention. 1,5 ... board, 2-4 ... sheet, 1a, 3a, 5a ... groove, 9a
~ 9d ... tank, 10a, 10b ... pump, 11 ... switching valve, 12 ... separation column, 13 ... suppressor, 14 ... detector
15 …… Temperature bath

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 30/02

Claims (2)

(57) [Claims] 1. A counter-ion of a cation is exchanged with a removal liquid for a counter ion of a cation from a liquid to be measured, from which a cation is separated by a separation column packed with a cation exchanger, to reduce the background of the liquid to be measured. A second sheet having a long groove through which the liquid to be measured separated from the cation flows, a granular anion exchange resin filled in the long groove of the second sheet, and an anion exchange membrane. A first sheet and a third sheet sandwiching the second sheet from both sides; and a substrate having a long groove through which the removing liquid flows, wherein the substrate flows through the long groove of the second sheet via the first sheet. A substrate having a long groove through which the liquid to be measured comes in contact with the removing liquid, and a substrate having a long groove through which the removing liquid flows, wherein the substrate to be measured flows through the long groove of the second sheet via the third sheet. Background removal apparatus characterized by comprising a second substrate provided so that the removing liquid is in contact with. 2. The method according to claim 1, wherein at least one of the first substrate and the second substrate has a long groove filled with an anion exchange resin, polymer beads, glass spheres, metal spheres, or a woven mesh sheet. Item (1).