Ion suppressor and ion chromatograph

Patent metadata

Field	Value
Publication number	US-11534700-B2
Application number	US-201716629385-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Jul 24, 2017
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

An ion suppressor includes ion exchange membranes between a pair of electrodes. Regeneration liquid channels are provided in the spaces between the electrodes and the ion exchange membranes, and an eluent channel is provided between the ion exchange membranes. Ion re-exchange in the eluent on the downstream side of the eluent channel is suppressed, thereby making it possible to improve the detection sensitivity for the ion to be measured. For example, the eluent channel has a folded structure, thereby increasing the amount of current on the downstream side of the eluent channel, and thus, the accumulation of ions is suppressed, and accordingly, ion re-exchange in the eluent can be suppressed.

First claim

The invention claimed is:

1. An ion suppressor that exchanges ions in an eluent from a separation column of an ion chromatograph, the ion suppressor comprising:
a first ion exchange membrane and a second ion exchange membrane are disposed between a pair of electrodes of a first electrode and a second electrode,
an eluent channel for allowing passage of the eluent from the separation column of the ion chromatograph is provided in a space between the first ion exchange membrane and the second ion exchange membrane,
a first regeneration liquid channel for allowing passage of a regeneration liquid that regenerates the first ion exchange membrane is provided in a space between the first electrode and the first ion exchange membrane,
a second regeneration liquid channel for allowing passage of a regeneration liquid that regenerates the second ion exchange membrane is provided in a space between the second electrode and the second ion exchange membrane, and
the eluent channel has a folded structure, where an introduction part for introducing the eluent from the separation column into the eluent channel and a discharge part for discharging the eluent from the eluent channel are disposed close to each other;
wherein the folded structure comprises a third ion exchange membrane provided between the first ion exchange membrane and the second ion exchange membrane, and
the eluent channel comprises a first eluent channel between the first ion exchange membrane and the third ion exchange membrane, and a second eluent channel between the second ion exchange membrane and the third ion exchange membrane.

2. The ion suppressor according to claim 1 , wherein
the first eluent channel and the second eluent channel are connected via an opening provided in the third ion exchange membrane to form the folded structure.

3. The ion suppressor according to claim 2 , wherein a first eluent channel support with an opening is disposed between the first ion exchange membrane and the third ion exchange membrane, and the opening provided in the first eluent channel support constitutes the first eluent channel,
a second eluent channel support with an opening is disposed between the second ion exchange membrane and the third ion exchange membrane, and the opening provided in the second eluent channel support constitutes the second eluent channel,
the first eluent channel is provided with the introduction part at one end in an eluent movement direction, and with an eluent transfer part for moving the eluent to the second eluent channel at the other end, and
the second eluent channel is provided with the discharge part at one end in the eluent movement direction, and with an eluent receiving part at a position corresponding to the eluent transfer part of the first eluent channel at the other end.

4. The ion suppressor according to claim 3 , wherein a mesh material capable of allowing passage of a liquid is provided in each of the opening of the first eluent channel support and the opening of the second eluent channel support.

5. The ion suppressor according to claim 4 , wherein the introduction part and eluent transfer part of the first eluent channel are narrower in channel width than a central part in the eluent movement direction, and
the eluent receiving part and discharge part of the second eluent channel are narrower in channel width than the central part in the eluent movement direction.

6. The ion suppressor according to claim 4 , wherein a shielding membrane for preventing contact between the second ion exchange membrane and a mesh material provided on and near the discharge part is provided between the second eluent channel support and the second ion exchange membrane.

7. The ion suppressor according to claim 1 , wherein the first ion exchange membrane and the second ion exchange membrane are cation exchange membranes.

8. The ion suppressor according to claim 7 , wherein the first electrode is a cathode and the second electrode is an anode.

9. A chromatograph comprising:
a separation column that separates an ion to be measured;
an electric conductivity meter that measures an electric conductivity of an eluent from the separation column; and
the ion suppressor according to claim 1 in a channel between the separation column and the electric conductivity meter,
wherein the chromatograph is configured to introduce the eluent from the separation column into the introduction part of the eluent channel of the ion suppressor, and guide the eluent discharged from the discharge part to the electric conductivity meter.

10. An ion suppressor that exchanges ions in an eluent from a separation column of an ion chromatograph,
wherein a first ion exchange membrane and a second ion exchange membrane are disposed between a pair of electrodes of a first electrode and a second electrode,
a first regeneration liquid channel for allowing passage of a regeneration liquid that regenerates the first ion exchange membrane is provided in a space between the first electrode and the first ion exchange membrane,
a second regeneration liquid channel for allowing passage of a regeneration liquid that regenerates the second ion exchange membrane is provided in a space between the second electrode and the second ion exchange membrane,
an eluent channel support with an opening is disposed between the first ion exchange membrane and the second ion exchange membrane,
a mesh material that allows passage of a liquid is provided in the opening provided in the eluent channel support, and the opening constitutes an eluent channel for allowing passage of the eluent from the separation column of the ion chromatograph,
the eluent channel is provided with a discharge part for discharging the eluent from the eluent channel, at one end in an eluent movement direction, and
a shielding membrane for preventing contact between a mesh material provided on and near the discharge part and the first ion exchange membrane and the second ion exchange membrane is provided each between the eluent channel support and the first ion exchange membrane and between the eluent channel support and the second ion exchange membrane.

11. The ion suppressor according to claim 10 , wherein the eluent channel is provided with an introduction part for introducing the eluent from the separation column into the eluent channel at an end opposite to the discharge part in the eluent movement direction, and
the shielding membrane is disposed to prevent contact between a mesh material provided on and near the introduction part and the first ion exchange membrane and the second ion exchange membrane.

12. The ion suppressor according to claim 10 , wherein a thickness of the shielding membrane is 1/10 or less of a thickness of the ion exchange membrane disposed adjacently.

13. A chromatograph comprising:
a separation column that separates an ion to be measured; an electric conductivity meter that measures an electric conductivity of an eluent from the separation column;
the ion suppressor according to claim 10 in a channel between the separation column and the electric conductivity meter,
wherein the chromatograph is configured to introduce the eluent from the separation column into the eluent channel of the ion suppressor, and guide the eluent discharged from the eluent channel to the electric conductivity meter.

Assignees

• Shimadzu Corp

Inventors

• Sakamoto Katsumasa

Classifications

• B01D15/08

  Selective adsorption, e.g. chromatography · CPC title

• G01N2030/965

  suppressor columns · CPC title

• G01N30/96

  using ion-exchange (G01N30/02, G01N30/90 take precedence) · CPC title

• G01N2030/027

  Liquid chromatography · CPC title

• B01D15/367 Primary

  Ion-suppression · CPC title