If you use trap columns in your eluent generator, you are familiar with their requirements: periodic removal, regeneration, and reequilibration off-line. Yet Dionex’s Continuously Regenerated Trap Columns never have to be taken off-line. Virtually maintenance free, the CR-TC allows the analyst to focus on what is most important—obtaining results.
The CR-TC offers:
Contaminant-free deionized source water and eluent
Time savings by not having to perform the regeneration off-line
Improved integration and increased sensitivity by providing very low baseline drift, even for gradients
Increased productivity by allowing quality data to be generated soon after start-up
Sample Pre-Treatment with the CR-CTC II
CR-TC Continuously Regenerated Trap Columns
With the introduction of the CR-TC electrolytically regenerated trap columns, Reagent-FreeTM IC systems with Eluent Generation (RFIC-EGTM systems) are truly reagent free. The CR-TC Trap Columns are designed for use with Eluent Generator modules including the ICS-2000, ICS-3000 EG, and RFC-30. These columns are an important component in anion-exchange applications using EGC II KOH cartridges or cation-exchange applications using EGC II MSA cartridges.
This device, when plumbed after the EGC Cartridge (see figure below), removes all anionic or cationic contaminants in the eluent continuously and provides a very low baseline drift during gradient operations.
What Are the Benefits?
Electrolytic generation of eluents and regeneration of trap columns offers many time-saving and technical benefits for the ion chromatography user because the only requirement is a source of deionized water.
For anion analysis, carbonate is a common contaminant in deionized source water and hydroxide solutions. For cation analysis, ammonium may be a contaminant. By trapping those contaminants continuously, CR-TCs produce eluents free of even trace contamination. The resulting baseline is not only lower and less noisy but drifts less, even during gradient runs. The benefits are improved integration and increased sensitivity (signal-to-noise). The CR-ATC trap columns replace the chemically regenerated ATC-HC and ATC-3 trap columns used in EGC II KOH applications. Likewise, the CR-CTC II trap column replaces the chemically regenerated CTC trap column used in EGC II MSA cation applications. The figure below illustrates the new CR-ATC trap column installed in an anion IC system. The Dionex eluent generator is installed between the IC pump and the injector valve. The concentration of eluent is directly proportional to the current supplied to the cartridge and inversely proportional to the flow rate.
Improved Performance
The figure below illustrates the improved baseline drift performance of the CR-ATC compared to the ATC-HC and a control (no trap column) for an IonPac® AS15 gradient. The advantage is decreased drift as a result of trapping anionic contaminants such as carbonate. The benefit is long-term operation, even for trace-level determinations, without regenerating the trap column, while improving sensitivity and thus analyte method detection limits (MDLs).
The figure below illustrates the ability of an RFIC-EG system to achieve immediate stable retention times after only one run when a CR-TC is installed. The benefit is increased productivity by allowing quality data to be generated soon after start-up.
How the CR-TC Functions
The figure below illustrates how the CR-ATC trap column functions. The CR-ATC consists of an anion-exchange resin bed with a cathode at the eluent outlet section. An anion-exchange membrane interface separates the anode from the eluent pathway. Anionic impurities (typically carbonate is a major contaminant in deionized source water and hydroxide solutions) are retarded by the anion-exchange bed and are driven toward the anode. The hydroxide generated at the cathode regenerates the bed whereas the hydronium generated at the anode combines with the removed anion contaminants to form acids. The hydroxide solution coming out of the CR-ATC device is thus free from anionic impurities.
The CR-CTC II works in a similar fashion, with a cation-exchange bed and membrane, and an anode at the outlet section for hydronium ion production. The figure below illustrates the performance of the CR-CTC II compared with the CTC and a control (no trap) for an IonPac CS12A gradient run using an EGC II MSA cartridge. The advantage is decreased drift as a result of trapping DI source water contaminants such as ammonium. The benefit is long-term operation, even for trace-level determinations, without regenerating the trap column. This low background improves analyte method detection limits (MDLs).
The ICS-2000 Ion Chromatography System
The CR-TC trap columns are an integral part of the ICS-2000 system. The ICS-2000 has a power supply that provides a constant voltage to the CR-TC Continuously Regenerated Trap Columns. The power to the CR-TC is turned on and shut off in concert with the power control to the EGC cartridge. No user intervention is required.
The ICS-3000 EG Eluent Generator
The CR-TC trap columns are an integral part of the new ICS-3000 EG Eluent Generator module. The ICS-3000 EG has two power supplies that provide constant voltage to up to two CR-TC Continuously Regenerated Trap Columns. The power to the CR-TC is turned on and shut off in concert with the power control to the EGC cartridge. No user intervention is required.
Customers with EG40 Eluent Generators: The EG40 CR-TC Add-on Kit
Dionex has extended the RFIC-EG capability to customers with EG40 Eluent Generators. Customers can upgrade their EG40 to operate the CR-TC, by installing an EG40 CR-TC Add-On Kit. This kit consists of a power supply, mounting bracket, and cabling. Installation can be easily accomplished by completing a few simple steps.
Customers with Early Model Detectors: The RFC-30 Reagent-Free Controller
Dionex has extended the RFIC-EG capability to customers with older IC systems. Customers without EG40 capability or full-range suppressor current control capability can now upgrade their system to Reagent-Free capability by purchasing the RFC-30 Reagent-Free Controller.
The RFC-30 Reagent-Free Controller provides current control to the SRS® and Atlas® suppressors, to the EGC cartridges and to the new CR-TC Continuously Regenerated Trap Columns.
