Intermittent electrolytic packed bed suppressor regeneration for ion chromatography

• US 5,773,615 A
• Filed: 02/13/1996
• Issued: 06/30/1998
• Est. Priority Date: 03/03/1995
• Status: Expired due to Term

• Current Assignee: Dionex Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Dionex Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Rabin, Steven B., Riviello, John M., Small, Hamish
• Primary Examiner(s): LUDLOW, JAN M
• Application Number:
  US08/600,856
• Time in Patent Office: 868 Days
• Field of Search: 736/161, 736/149, 736/175, 422/82.02, 422/70, 210/635, 210/656, 210/198.2, 210/670, 73/61.52, 73/61.53, 73/61.55, 73/61.58, 204/130, 204/131, 204/187.4, 204/272
• US Class Current: 436/161
• CPC Class Codes: G01N 2030/965 suppressor columns
• CPC Class Codes: G01N 30/96 using ion-exchange G01N30/02, G01N30/90 take precedence
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials

Abstract

Method and apparatus for ion chromatography including passage of sample through a chromatographic separation column, through a suppressor column containing a resin with exchangeable ions, and then through a detector. The suppressor column is equipped with an electrical potential supplying device to electrolyze water and regenerate the suppressor column.

Claims

1. A method of anion or cation analysis by ion chromatography using periodic electrolytic chemical regeneration of a packed bed suppressor, said method comprising

(a) chromatographically separating ionic species in a first liquid sample in a water-containing first eluent solution comprising electrolyte, to form a first chromatography effluent including separated ionic species,

(b) flowing said first chromatography effluent through a first packed bed suppressor including first suppressor ion exchange resin with first exchangeable ions to convert said electrolyte to weakly ionized form during suppression, thereby depleting at least some of said first exchangeable ions on said first suppressor ion exchange resin, said first chromatography effluent exiting as a first suppressor effluent,

(c) flowing the first suppressor effluent including the separated ionic species from said first packed bed suppressor through a first detector in which the separated ionic species are detected to form a detector effluent, and

(d) applying an electrical potential through said first packed resin bed suppressor while flowing an aqueous liquid stream therethrough to electrolyze water in said aqueous liquid stream and thereby regenerate the first exchangeable ions on said first suppressor ion exchange resin, the application of said electrical potential being discontinued during steps (a), (b) and (c).

2. The method of claim 1 in which the ionic species are anions and in which in step (d) water in said aqueous liquid in said first packed bed suppressor is electrolyzed to generate hydronium ions for regeneration of said first exchangeable ions.

3. The method of claim 1 in which the ionic species are cations and in which in step (d) water in said aqueous liquid in said first packed bed suppressor is electrolyzed to generate hydroxide ions for regeneration of said first exchangeable ions.

4. The method of claim 1 further comprising:

(e) flowing a second water-containing eluent solution comprising electrolyte through a flow-through polishing unit comprising ion exchange resin having exchangeable ions to convert said electrolyte into weakly ionized form and to form a polished liquid effluent, and

(f) flowing said polished liquid effluent through said first packed bed suppressor during step (d), said polished effluent comprising said aqueous liquid stream.

5. The method of claim 1 in which said aqueous liquid stream comprises a second water-containing eluent solution.

6. The method of claim 1 in which said aqueous liquid stream is supplied from a source of water independent of said eluent solution.

7. The method of claim 6 in which said water from said source independent of said eluent solution is deionized water.

8. Apparatus for analysis of ions in a liquid sample solution comprising

(a) a reservoir for a water-containing eluent solution comprising electrolyte,

(b) chromatographic separating means in communication with said eluent reservoir for receiving eluent therefrom, said chromatographic separating means comprising a chromatographic separating medium adapted to separate ionic species of a sample eluted therethrough using said eluent solution,

(c) means for injecting a liquid sample into said chromatographic separation means,

(d) a suppressor comprising an ion exchange resin bed in communication with said chromatographic separating means,

(e) means for applying an electrical potential through said first suppressor ion exchange resin bed to electrolyze water and regenerate said suppressor ion exchange resin, and

(f) a detector in communication with said suppressor.

9. Apparatus for analysis of ions in a liquid sample solution comprising

(a) a first reservoir for a water-containing eluent solution comprising electrolyte,

(b) chromatographic separating means in communication with said eluent reservoir for receiving eluent therefrom, said chromatographic separating means comprising a chromatographic separating medium adapted to separate ionic species of a sample eluted therethrough using said eluent solution,

(c) means for injecting a liquid sample into said chromatographic separation means,

(d) a suppressor comprising an ion exchange resin bed in communication with said chromatographic separating means,

(e) a detector in communication with said suppressor,

(f) a second reservoir of water in communication with said suppressor,

(g) means for applying an electrical potential through said suppressor ion exchange resin bed to electrolyze water in a flowing aqueous stream and regenerate said suppressor ion exchange, and

(h) valve means including a first and second valve position, said first valve position permitting liquid flow from said first reservoir, through said chromatographic separation means, suppressor, and said detector, and said second position permitting liquid flow from said second reservoir, through said suppressor, whereby in said first valve position, the ions in a sample solution are separated in said chromatographic separating means and carried in said eluent through said suppressor in which said electrolyte is converted to weakly dissociated form during suppression, and through said detector in which the ions are detected, and in said second valve position, water from said second reservoir flows at least through suppressor, said applying means being capable of applying said electrical potential across said suppressor ion exchange resin bed to regenerate said suppressor ion exchange resin bed with said valve means in said second valve position.

10. A method of anion or cation analysis by ion chromatography using periodic electrolytic chemical regeneration of a packed bed suppressor, said method comprising

(a) chromatographically separating ionic species in a first liquid sample a water-containing first eluent solution comprising electrolyte, to form a first chromatography effluent including separated ionic species,

(b) flowing said first chromatography effluent through a first packed bed suppressor including first suppressor ion exchange resin with first exchangeable ions to convert said electrolyte to weakly ionized form during suppression, thereby depleting at least some of said first exchangeable ions on said first suppressor ion exchange resin, said first chromatography effluent exiting as a first suppressor effluent,

(c) flowing the first suppressor effluent including the separated ionic species from said first packed bed suppressor through a first detector in which the separated ionic species are detected to form a detector effluent,

(d) applying an electrical potential through said first packed resin bed suppressor while flowing an aqueous liquid stream therethrough to electrolyze water in said aqueous liquid stream and thereby regenerate the first exchangeable ions on said first suppressor ion exchange resin, the application of said electrical potential being discontinued during steps (a), (b) and (c),

(e) flowing a second water-containing eluent solution comprising electrolyte through a flow-through polishing unit comprising ion exchange resin having exchangeable ions to convert said electrolyte into weakly ionized form and to form a polished liquid effluent, and

(f) flowing said polished liquid effluent through said first packed bed suppressor during step (d), said polished effluent comprising said aqueous liquid stream.

11. The method of claim 10 further comprising the steps of

(g) regenerating the ion exchange resin in said polishing column by flowing the effluent from said first detector in step (c) through said polishing unit and applying an electrical potential through said polishing column ion exchange resin to regenerate the exchangeable ions thereon.