Reagent-Free Ion Chromatography (RFIC) Eluent Regeneration

Non-stop operation for up to four weeks

Eluent preparation, calibration, and equilibration take operator and instrument time away from analysis. Dionex Reagent-Free IC with Eluent Regeneration (RFIC-ER) gives you non-stop operation from one batch of eluent for up to four weeks by automatically regenerating eluent, saving time and labor. One 4L batch of eluent lasts up to four weeks.

What is eluent regeneration?

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.

What is the difference between eluent generation and eluent regeneration?

  • 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.

What applications are suitable for RFIC-ER?

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.

How does RFIC-ER work?

  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.

Eluent regeneration using a Thermo Scientific suppressor

Eluent regeneration using a Thermo Scientific™ suppressor

What benefits does eluent generation provide?

  • 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

How reproducible is RFIC?

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.

Day-to-Day Reproducibility of Standards

Day-to-day Reproducibility of Standards

Overlay of seven daily calibration check standards separated on a Dionex ICS-1500 RFIC-ER system using regenerated carbonate/ bicarbonate eluent.

Change in % Peak Area Over 28 Days

Change in % Peak Area Over 28 Days

Percent peak area changes over 28 days for a seven-anion calibration check standard separated using a 4mm Dionex IonPac AS22 column on a Dionex ICS-1500 RFIC-ER system with regenerated carbonate/ bicarbonate eluent. The system passed the daily calibration check for an entire month, requiring only one 4L bottle of eluent.

Which systems support RFIC-ER technology?

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

What eluent regeneration consumables are available?

Chromeleon CDS Software Resources

Here’s a collection of resources to learn about the feature sets that make this software both powerful and easy to use.