JPH01169353A - Background remover - Google Patents

Abstract

PURPOSE:To remove a conductivity back ground without impairing a peak shape from an eluate from a separation column for cation analysis, by making a mobile phase flow through a passage sandwiched by anion exchange films while doing a removing liquid flow through an external passage. CONSTITUTION:An acrylic first substrate 1, a first rubber sheet 2 provided with a groove 2a at the center thereof, a second sheet 3 comprising a sheet-like ion exchange film, a third rubber sheet 4 provided with a groove 4a at the center thereof, a fourth sheet 5 comprising a sheet-like ion exchange film, a fifth rubber sheet 6 provided with a groove 6a at the center thereof and a second acrylic substrate 7 are laminated. A filler, for example, comprising anion exchange resin is packed into the groove 2a of the first sheet 2, the groove 4a of the third sheet 4 and the groove 6a of the fifth sheet 6. An eluate from a separation column for anion analysis flows to the groove 4a of the third sheet 4 and a removing liquid of NaNO3, NaOH or the like does to the groove 2a of the first sheet 2 and the groove 6a of the fifth sheet 6.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention removes the conductivity background of a liquid eluted from a separation column that is attached to a cation analyzer that analyzes cations in a liquid to be measured. The present invention relates to a background removal device.

<Conventional technology>.

-Jl'J, to analyze cations in the liquid to be measured,
A fixed amount of the liquid to be measured is transferred to a separation column packed with a cation exchanger with a low ion exchange capacity using a mobile phase consisting of a dilute acid, and the cations in the liquid to be measured are chromatographically separated. I was trying to analyze it. In addition, the liquid eluted from the separation column can be detected directly with a detector (for example, a conductivity detector). ″
By placing a suppressor column made of a type anion exchange resin and passing the mobile phase through the suppressor column, the acid is converted to water, and the counter ions of the cations in the liquid to be measured are changed to hydroxide ions. Cations in a liquid to be measured are measured while improving the S/N ratio by lowering the conductivity of the mobile phase. In this case, if an anion exchange membrane can be used instead of a suppressor column packed with an OH-type anion exchange resin, then
Continuous anion exchange P! via the anion exchange membrane! Since the acid serving as the mobile phase can be continuously converted to water by A, it is extremely convenient for using a cation analyzer.

<Problems to be Solved by the Invention> However, as a conventional example of a suppressor using an anion exchange membrane, Japanese Patent Application No. 55-151555 (title of the invention ``Method for analyzing cations contained in a sample liquid and suppressor (hereinafter referred to as "the first suppressor") listed in the
The suppressor described in Japanese Patent Application No. 55-145353 (title of invention ``Method and apparatus for analyzing cations contained in sample liquid'')
(hereinafter referred to as "second conventional example") is publicly known.

That is, the first conventional example is a suppressor made of an anion exchange membrane tube with a double tube structure. In addition, the second conventional example uses an anion exchange membrane tube as a suppressor and applies a DC voltage to an electrode provided inside the inner tube and an electrode provided outside the outer tube, and a sheet-like anion exchange membrane tube is used as a suppressor. Two ion exchange membranes and a spacer were stacked to provide a flow path for the mobile phase on the inside and a removal liquid flow path on the outside.An electrode was provided outside the flow path and a DC voltage was applied. It is.

However, the first conventional example has disadvantages in that anion exchange membrane tubes are difficult to obtain and manufacturing and processing are more complicated than in the case of a suppressor column filled with an anion exchange resin. In addition, the second conventional example had the disadvantage that anion exchange membrane tubes were difficult to obtain, difficult to manufacture and process, and cations were attracted to the cathode, resulting in poor peak shapes in the chromatogram. .

The present invention has been made in view of the drawbacks of the conventional examples, and its purpose is to provide a background removal device with a simple configuration using an easily available sheet-like anion exchange membrane and anion exchange i-finger. It is about providing.

Means for Solving the Problems> The feature of the present invention that solves the problems described above is that in a background removal device, a first sheet having a long groove filled with a first filler and an anion exchanger are used. a second sheet made of a membrane, a third sheet having a long groove filled with a second filler, a fourth sheet made of an anion exchange membrane, and a fifth sheet filled with the third filler and having a long groove. are stacked and sandwiched between the first and second substrates from both sides, and the mobile phase is caused to flow through the gap flow path formed by the second to fourth sheets, and the second sheet is formed outside the second sheet. The purpose of the present invention is to allow the removal liquid to flow through the gap flow path formed on the outer side of the fourth sheet.

<Example> Hereinafter, the present invention will be described in detail using the drawings. 1st
The figure is an exploded perspective view of the embodiment of the present invention, and FIG. 2 is an explanatory diagram of the structure of an example of use of the embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a first substrate made of, for example, an acrylic plate, la1 to la
,. 1b is a through hole provided in the first substrate 1, and 1b is a through hole 1 provided in the first substrate 1.
The bolt inserted into a1, IC is the eluent inlet, 1
d is the first inlet for the removal Shibukawa, 1e is the outlet for the solution M,
1f is the first outlet of the removal Shibukawa, 2 is in the center? F! 2a
3 is a second sheet made of a sheet-shaped anion exchange membrane, 4 is a groove 4 in the center.
5 is a fourth sheet made of a sheet-shaped anion exchange membrane, 6 is a fifth sheet made of rubber, for example, and has an eraser 6a in the center; 7 is, for example, A second substrate made of an acrylic plate, 7a+ to '7a+O are through holes provided in the second substrate 7, 7C is a second inlet for the removed liquid phase, 7d is a second outlet for the removed liquid phase, and Ra is a washer. , 8b is a nut that engages with the threaded portion of bolt lb. Note that the long groove 2a of the first sheet eraser 2.

The long groove 4a of the third sheet 4 and the long groove 6a of the fifth sheet 6
In each case, a filler (for example, an anion exchange resin) is embedded.

The embodiment of the present invention having the above-mentioned exploded configuration is the first
~ After the fifth sheets 2 to 6 are laminated, the sheets 2 to 6
is sandwiched between the first and second substrates 1 and 7, and then the bolts 1b, (and bolts 1b2 to 1b+o (not shown)
) is the through hole 1a1 (and the through holes 1a2 to 1 alo
) and through hole 7a1 (and through J hole 7a=~7a+o)
After the washer 8a1 (and the washers Ra2 to 8a, not shown) is inserted, the bolt 1b1 (and the bolts 1b2 to 1b+o, not shown) are inserted.
A nut 8b (and a nut 8b2 (not shown)
~8b7. ) are screwed together to complete the assembly of the background removing device according to the embodiment of the present invention. The back ground removing device thus assembled is used by being attached to a cation removing device as shown in FIG. That is, FIG. 2 is an explanatory diagram of the configuration of an example of use of the embodiment of the present invention, and in the figure, the column 12. Suppressor 13. The detector 14 is housed in a constant temperature 'W115 and maintained at a constant temperature (for example, 45°C). Moreover, when the pump 10a is driven, the melt M8 in JflJ Q a! For example, 1
7W/,/min.

At the flow rate of pump 10a → first and second connection ports 11a and llb of switching valve 11 → separation column 12 → inlet 1C of internal chamber 13b of background removal device 13 → back ground removal device 13 Inner chamber 13b→ Outlet 1e of inner chamber 13b of bag gland removal device 13→Flows through detector 14 to waste tank 9C, and when pump 10b is driven, tank 9
The removal liquid in b has a flow rate of, for example, 1 mlF/min,
Pump 10b → back ground removal device? i! 13, the first introduction hole 1d of the outer chamber 13c → back ground removal device [13
Outer chamber 13c → t$1 outlet 1f of outer chamber 13C → Outer chamber 1
3C, the liquid flows through the second introduction lower c of the back ground removing device 13, the outer chamber 13c of the back ground removing device 13, and the second outlet lower d of the outer chamber 13c, and then flows to the waste liquid tank 9d. For this reason, the background removal device 1
The cations contained in the liquid flowing in the inner chamber 13b (groove 4a in FIG. 1) of 3 are removed from the background through the anion exchange membrane 13a (second sheet 3 and fourth sheet 5 in FIG. 1). The ion exchange 1, 7 with the cations contained in the liquid flowing in the outer chamber 13C of the removal device 13 (the side 2a and the side 6a in FIG. 1) ultimately reduces the background of conductivity.

FIG. 3 is a conceptual diagram showing in detail the principle of conductivity background reduction (removal) as described above. That is, three chambers CI, C2+ c separated by anion exchange membrane M
, is filled with a filler such as anion exchange resin R, and the wasted volume is reduced. In addition, room C/2 contains eluents and test liquids (for example, HNO) that are not eluted from the separation column.

and Na, N 03 ) flow, and a removal liquid (for example, Na OH) flows in the chambers CI and C3 in the countercurrent direction to the eluent.
is flowing. In this state, the No, -'' ions contained in the eluent and measurement solution (e.g., HN O3 and NaN0.) in the room C2 are removed from the removal solution (e.g., NaN O) in the rooms C, C3. The liquid eluted from chamber C2 is ion-exchanged with the OH- ions contained in the OH- ions (H2O and The liquid eluted from chambers C1 and C3 is a liquid with high conductivity (e.g. NaOH and NaN03).
It becomes a solution containing.

FIG. 4 is a chromatogram as an experimental result showing the reduction (removal) of the conductivity background as described above. That is, 1
First, water (H2O) as a removing liquid is flowed into the outer chamber 13C of the background removing device 13 in FIG. 2 (the grooves 2a and 6a in FIG. 1). 577F in 13b (Spring 4a in Figure 1),
The conductivity detected by the detector 14 while flowing the eluent consisting of tNOi solution (with a concentration of M) was 1°76 m, S/cm, as shown in Fig. 4. In the figure, at this time, using a syringe or the like (not shown), the liquid to be measured containing 2 a op pm of Na, ions is fixed at the 48th connection port of the first switching valve 11!
(For example, if 100 μm is injected, the measuring tube 11g will be filled with the liquid to be measured. In this state, the switching valve 11 is turned on and the internal flow path changes from the solid line connection state in Fig. 2 to the broken connection state. When the metering tube 11g is switched to
The liquid to be measured inside is transported by an eluent to the separation column 12, and the cations in the liquid to be measured are separated by chromatography. Thereafter, the conductivity background is reduced as described above through the suppressor 13, and then the detector 1
Detected at 4. The signal detected by the detector 14 in this manner is guided to a display device (for example, a recorder) not shown, and a romatogram as shown in A of FIG. 4 is drawn. In this chromatogram, first, the peak of anions (specifically CI- ions, which are counter ions) appears in the direction of increasing conductivity, and then the peak of Na+ ions appears in the direction of decreasing conductivity. When the liquid was switched from water to an NaOH solution with a concentration of 100 m, M, the conductivity immediately decreased to 0.92 m, 3 after about 20 minutes.
7cm, roar.

In this state, using a syringe (not shown) or the like, a liquid to be measured containing 200 pp of Na+ ions is added to the fourth valve of the first switching valve 11.
After a certain amount of Jl (for example, 100μ!) is injected into the connection port lie, the switching valve 11 is turned on and the fourth
A chromatogram as shown in figure B is obtained. In this chromatogram, the peak of anions (specifically, Cl- ions serving as counter ions) does not appear, and the peaks of Na and + ions also appear in the direction of increasing conductivity. As is clear from comparing the EIc of the chromatogram shown in Figure 4A and the chromatogram shown in Figure 4B, the baseline conductivity changes from 1.76m, 37cm to o, 92m, s/cm. 1. /1900. On the contrary,
The peak sizes of Na+ ions are almost the same, and S
It can be seen that the /N ratio has been significantly improved.

<Effects of the Invention> According to the embodiments of the present invention as described in detail above, a dead volume that does not impair the peak shape in a chromatogram is achieved by using an easily available flat anion exchange membrane and anion exchange resin. A background removal device with a small and simple configuration is realized. In addition, a filler such as an anion exchange resin is placed in the space (specifically, the long grooves 2a, 4b, 6b) formed by the anion exchange membrane and the spacer (first to fifth sheets 2 to 6). Since the anion exchange resin is filled, there is also the advantage that the anion exchange resin backs up the anion exchange membrane and increases the withstand pressure of the flow system through which the eluent flows. Furthermore, the space formed by the anion exchange membrane and the spacer (first to fifth sheets 2 to 6) (specifically, the long groove 2
Even if the filler filled in a, 4b, 6b) is a polymer bead, a glass sphere, or a metal sphere, the same effect appears and is effective.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view of an embodiment of the present invention, Fig. 2 is an explanatory diagram of a configuration of an example of use of the embodiment of the invention, Fig. 3 is a conceptual diagram showing the principle of conductivity background removal in detail, and Fig. 4 is This is a chromatogram.

Claims (4)

[Claims] (1) In a background removal device that is attached to a cation analyzer that analyzes cations in a liquid to be measured and that removes the conductivity background of a liquid eluted from a separation column, a long groove filled with a first packing material is used. a first sheet having
a second sheet made of an anion exchange membrane, a third sheet having a long groove filled with a second filler, a fourth sheet made of an anion exchange membrane, and a third sheet having a long groove filled with a third filler. 5 sheets are laminated and sandwiched between the first and second substrates from both sides, and the mobile phase is flowed into the gap flow path formed by the second to fourth sheets, and is formed on the outside of the second sheet. A background removal device characterized in that a removal liquid is caused to flow through a gap flow path formed on the outside of the fourth sheet and a gap flow path formed on the outside of the fourth sheet. (2) The background removing device according to claim (1), wherein the first to third fillers are all made of anion exchange resin. (3) The first and third fillers are polymer beads, glass spheres, or metal spheres according to claim (1).
Background removal device as described in section. (4) The second filling may include polymer beads, glass spheres,
or a metal ball.