Metrosep C Supp 2 (Column manual)

Significance of the topic

Ion chromatography of cations, transition metals and amines with sequential chemical suppression provides high sensitivity (µg/L detection limits) and low baseline noise. It is vital for environmental monitoring, industrial quality control, pharmaceutical analysis and academic research.

Objectives and overview of the manual

This manual presents a complete workflow for the Metrosep C Supp 2 separation column: ordering details, technical specifications, column handling, eluent preparation, instrument start-up, method parameters, application examples and troubleshooting.

Methodology and instrumentation

• Stationary phase: 5 µm polystyrene/divinylbenzene copolymer with carboxyl groups, dimensions 100–250×4.0 mm.
• Guard column: Metrosep C Supp 2 Guard/4.0 recommended to protect the analytical column.
• Eluent: 5.0 mmol/L HNO₃ with 50 µg/L Rb as internal standard, degassed and filtered.
• Suppression: Sequential chemical suppression modules (MSM-HC C and MCS).
• Detector: Conductivity.
• Typical conditions: 1.0 mL/min flow rate, 40 °C column temperature, 20 µL injection loop.
• Chemicals: p.a. grade nitric acid (2 mol/L stock), RbNO₃, ultrapure water (≥18.2 MΩ·cm).

Main results and discussion

• Standard separation of Li, Na, NH₄, K, Mg and Ca with baseline noise <0.1 nS/cm.
• Temperature effect: higher temperatures accelerate retention times, with non-uniform shifts for K and Rb.
• Flow rate effect: linear decrease in retention times with higher flow.
• Eluent strength: increasing HNO₃ disproportionally accelerates polyvalent cations, potential co-elution at high concentration.
• Organic modifiers (up to 20% acetone or acetonitrile) reduce retention times but may broaden peaks.
• Applications include µg/L trace analysis, non-suppressed detection, separation of cations in the presence of transition metals, dose-in gradient methods, rapid four-cation screening in <5 min and amine determination.

Benefits and practical applications

The Metrosep C Supp 2 column delivers high reproducibility, low detection limits, broad pH (0–12) and temperature stability (10–60 °C), compatibility with organic solvents and flexible method adaptation. Guard columns and inline filtration extend column life and protect against particulate or biological contamination.

Future trends and potential uses

Emerging directions include automated inline sample preparation, coupling with mass spectrometry, high-throughput gradient techniques, field-deployable miniaturized IC units, and development of universal suppressors and more robust stationary phases to broaden the scope of environmental and clinical analyses.

Conclusion

With proper column care, eluent management and adherence to recommended operating procedures, the Metrosep C Supp 2 system offers a robust, sensitive and versatile platform for routine and advanced cation analysis across diverse matrices.

References

• Brochure: Cation suppression in ion chromatography – Cation determination in the trace range (Metrohm AG).
• Application Notes CS-016 to CS-020, Metrohm AG.