RFIC Systems with Eluent Regeneration

Cost-Effective Time and Labor Savings

Advances in IC automation have simplified operation while increasing precision and accuracy. However, eluent preparation, calibration, and equilibration still take operator and instrument time away from analysis. To save time and labor, Eluent Regeneration was developed for systems dedicated to high-throughput analyses of samples with low- to moderate-concentration matrices. Reagent-Free ^TM IC systems with Eluent Regeneration (RFIC-ER ^TM systems) are designed to use carbonate, carbonate/ bicarbonate, or MSA eluents for isocratic separations. Eluent Regeneration is available as an optional configuration or upgrade for ICS-1000, -1500, -2000, and -3000 systems.

Eluent regeneration uses the suppressor to reconstitute the starting eluent, allowing use of a single 4-L bottle of eluent for up to four weeks. Because the system is a closed loop, it can run continuously, eliminating the need for recalibration or reequilibration during the 28 days of non-stop operation. Eluent preparation and waste disposal are both reduced from approximately 48 L to 4 L per month, reducing not only labor but also costs for materials and hazardous waste disposal.

Regenerating Eluent

The same electrolytic process that suppresses eluent for detection is used to regenerate eluent for reuse. After detection, suppressed eluent is passed through an analyte trap column to remove the analyte ions. 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. A catalytic column recombines the oxygen and hydrogen to form water. The suppressor effluent is then returned to the eluent reservoir for reuse. Because the electrolysis gases are recombined stoichiometrically, no water is lost in the system and eluent concentration remains constant. A purification column is plumbed after the pump to further assure eluent purity.

Care-Free Consistency

Eluent regeneration not only reduces labor, it also increases consistency over manual eluent preparation. Because the same eluent is used for up to four weeks, variations in preparation procedures are eliminated. Stable eluent concentration yields reproducible results, with little variability in peak retention times or areas. The system does not need to be recalibrated as it would if eluent were prepared manually. A routine calibration check standard is sufficient to assure accuracy. Because the system forms a closed loop, it can be left running without the need to empty waste or prepare eluent for up to four weeks. Continuous operation eliminates the need to reequilibrate, and with no need to prepare eluent, all the operator has to do is load samples. This means higher sample throughput and more time for operators to pursue other tasks. Pump maintenance is also reduced, since the flowing eluent has no chance to crystallize on pump surfaces. Eluent can be regenerated for up to four weeks for analysis of samples with low- to moderate-concentration matrices, such as drinking water. Higher injection volumes or heavy workloads may require more frequent replacement or regeneration of trap and purification columns and eluent. Chromeleon software wellness features monitor eluent, trap, and column usage, and alert operators when replacement or regeneration is necessary.

Overlay of seven daily calibration check standards separated on an ICS-1500 RFIC-ER system using regenerated carbonate/ bicarbonate eluent. RFIC-ER systems can run for up to a month using a single eluent preparation without requiring recalibration or reequilibration.

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

Carbonate eluent regenerated using an ASRS^® 300 suppressor.