Intermittent electrolytic packed bed suppressor regeneration for ion chromatography

DETAILED DESCRIPTION The present invention relates to ion chromatography using electrochemical regeneration of a packed bed suppressor.
Method and apparatus are provided using electrolytic chemical regeneration of a packed bed suppressor containing ion exchange resin.
Ion chromatography is performed in a conventional manner by chromatographic separation, chemical suppression in a packed bed and detection.
Thereafter, and before a second run, an electrical potential is passed through the packed bed suppressor while flowing an aqueous stream through it to electrolyze water in the stream and thereby create hydronium or hydroxide ions to regenerate the ion exchange resin.
The packed bed suppressor with capacity sufficient for several analyses, has electrodes embedded in the resin, which permits electrochemical regeneration.
Electrochemical regeneration is performed after one analysis, or after many analyses, depending on the capacity of the packed bed suppressor.
In one embodiment, the aqueous liquid stream is the eluent.
In another embodiment, the aqueous liquid stream is an independent water source, preferably deionized water.
In that instance, appropriate valving is provided so that after a run, the deionized water is passed through the bed and electrolyte bypasses the bed, while the electrical potential is being applied to regenerate the resin.
In a further embodiment, a second ion exchange resin bed is used with suitable valving to pass liquid streams through the system.
In one alternative of this system, a second sample in an eluent stream is chromatographically separated, typically on a chromatographic column using an eluent.
The eluent and separated second sample flow through a second packed bed suppressor including ion exchange resin to convert the electrolyte to weakly ionized form.
Then, the separated sample ionic species in the suppressor effluent are detected in the detector.
The effluent then flows through the first packed bed suppressor, forming the aqueous liquid stream required for regeneration and an electrical potential is applied and regeneration of the first packed bed suppressor is accomplished