Thermo Scientific Dionex eluent suppressors for ion chromatography

Importance of the Topic

Ion chromatography relies on eluent suppression to reduce background conductivity and improve detection sensitivity.
Advancements in suppressor technology are critical for high-resolution separations and seamless integration with modern detectors.

Study Objectives and Overview

This document reviews three Thermo Scientific™ Dionex™ suppressors: NGES Next Generation Electrolytic Suppressor, CRS 500 Chemically Regenerated Suppressor and ACRS-ICE 500 Ion-Exclusion Suppressor.
It outlines their design innovations, performance characteristics and application scopes.

Methodology and Instrumentation

The suppressors differ in regeneration principles and formats:

• NGES: Electrolytic self-regeneration, available in 2 mm and 4 mm, compatible with both anion and cation analysis and optimized for 4 µm columns.
• CRS 500: Chemical regeneration for high capacity, solvent tolerance and very low noise, offered in standard bore (4 mm) and microbore (2 mm).
• ACRS-ICE 500: Chemically regenerated suppressor for ion-exclusion applications in 4 mm and 9 mm formats.

Key design elements include a uniformly packed ion-exchange resin chamber, dual-membrane technology for enhanced backpressure resilience and reagent-free electrolytic regeneration for reagent-sensitive analyses.

Main Results and Discussion

Performance highlights include:

• Up to 30–40 % gain in peak efficiency when NGES is paired with 4 µm columns.
• High suppression capacities (e.g., 200 µeq/min for anion, 4 mm NGES; 100 µeq/min for cation, 4 mm NGES).
• Backpressure tolerance up to 500 psi for NGES and up to 60 psi for CRS 500.
• Low void volumes (<15 µL to <50 µL) supporting narrow, well‐defined peaks.

Electrolytic suppression reduces non-volatile ion load in mass spectrometry, enhancing long-term stability and lowering maintenance.

Benefits and Practical Applications

The Dionex suppressors deliver:

• Streamlined operation without external regenerant chemicals (NGES).
• Improved quantitation precision through sharper peak shapes.
• Compatibility with diverse eluent compositions, including organic modifiers.
• Enhanced system uptime and stable performance in hyphenated techniques (IC-MS).

Future Trends and Opportunities

Emerging directions in suppressor technology include:

• Further miniaturization for microfluidic and portable IC systems.
• Integration with sub-4 µm particle columns and ultrahigh-pressure IC configurations.
• Advanced self-regeneration modules with automated monitoring and control.
• Tighter coupling to hyphenated platforms such as IC-MS and IC-NMR for comprehensive analyte profiling.

Conclusion

Thermo Scientific™ Dionex™ suppressors offer versatile regeneration modes and formats to meet the demands of modern ion chromatography.
The NGES Next Generation Electrolytic Suppressor stands out for its reagent-free operation, high efficiency and compatibility with advanced column technologies.
Choosing the appropriate suppressor depends on eluent chemistry, sensitivity requirements and integration with downstream detectors.