Reagent-Free Ion Chromatography Eluent Regeneration

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• What is eluent regeneration?
• What is the difference between eluent generation and eluent regeneration?
• What applications are suitable for RFIC-ER?
• How does RFIC-ER work?
• What benefits does eluent generation provide?
• How reproducible is RFIC-ER?
• Which systems support RFIC-ER technology?
• What regeneration consumables are available? 

In an ion chromatography (IC) system with eluent regeneration, effluent that would otherwise flow to waste is directed to an electrolytic device and regenerated, to be used again as fresh eluent.

RFIC-ER makes use of the electrolytic suppressor to regenerate the returning eluent. In this closed-loop system, one batch of original eluent provides non-stop operation for up to four weeks. This closed-loop system eliminates errors due to eluent preparation, provides a stable environment that does not need recalibration, and is “always ready’ for the next analysis.

• Systems with RFIC-ER employ the electrolytic suppressor to regenerate eluent. RFIC-ER systems are typically dedicated to isocratic separation of anions or cations using carbonate or methanesulfonic acid (MSA) eluent for low to moderate-concentration sample matrices.
• Systems with Reagent-Free Eluent Generation, (RFIC-EG) generate eluent electrolytically using deionized water and eluent generation cartridges (EGCs). RFIC-EG systems are recommended for applications that require hydroxide eluents or gradient separations.
• RFIC-ER is a low-cost alternative to RFIC-EG.

RFIC-ER was developed for:

• Use in isocratic separations using carbonate, carbonate/bicarbonate, or MSA eluent
• Systems dedicated to high-throughput analyses of samples with low- to moderate-concentration matrices, such as those dedicated to the analysis of drinking, ground, and surface waters

Higher injection volumes or heavy workloads may require more frequent replacement or regeneration of trap and purification columns and eluent. For applications that require hydroxide eluents or eluent gradients, RFIC-EG systems are recommended.

1. 4L of eluent is prepared in the normal manner.
2. After detection, suppressed eluent is passed through an analyte trap column to remove the analyte ions.
3. The suppressed eluent is then returned to the suppressor to provide the water for electrolytic suppression. The effluent from the suppressor contains the eluent ions and H₂ and O₂ gases.
4. A catalytic column recombines the oxygen and hydrogen to form water. Because the electrolysis gases are recombined stoichiometrically, no water is lost in the system and eluent concentration remains constant.
5. The suppressor effluent is then returned to the eluent reservoir for reuse.
6. A purification column is plumbed after the pump to further ensure eluent purity.

• Saves in labor and time, material, and hazardous waste-disposal costs
• The system is ‘Always Ready’
  • Because the system runs continuously in a closed-loop, the system remains fully equilibrated and calibrated; a routine calibration check standard is sufficient to assure accuracy
  • Increases reproducibility with little variability in peak retention times or areas compared to frequent manual eluent preparation
  • Reduces pump maintenance; flowing eluent has no chance to crystallize on pump surfaces
• High performing
  • Eliminates variations in eluent preparation
  • Higher sample throughput
• Automated
  • The Dionex Chromeleon Chromatography Data System (CDS) software wellness features monitor eluent, trap, and column usage, and alert operators when replacement or regeneration is necessary

Day to day reproducibility is high. This data show an overlay of seven daily calibration check standards separated on a Dionex ICS-1500 RFIC-ER system using regenerated carbonate/ bicarbonate eluent.

RFIC-ER is an optional configuration or upgrade for Dionex Integrion and ICS-5000+ HPIC systems.

Go to: IC Eluent Regeneration (ER) Consumables