Metrosep A Supp 5 (Column manual)

Importance of the Topic

Reliable separation of inorganic and small organic anions is critical in water quality control, environmental monitoring, industrial process analysis and pharmaceutical quality assurance. The Metrosep A Supp 5 column family offers high plate count, excellent peak symmetry and broad chemical compatibility, making it a versatile choice for routine ion chromatographic workflows. Its robust design minimizes maintenance and extends column lifetime, while allowing straightforward adaptation to diverse sample matrices and analytical challenges.

Objectives and Study Overview

This document presents a comprehensive guide for the Metrosep A Supp 5 anion exchange columns. Key aims include:

• Describing column specifications, ordering options and storage conditions
• Detailing eluent preparation and system start-up procedures
• Illustrating application examples across standard anion analysis, regulated methods (e.g. EPA 218.7) and challenging matrices
• Providing troubleshooting advice and regeneration protocols

Methodology and Instrumentation

The Metrosep A Supp 5 series employs a polyvinyl alcohol–based resin functionalized with quaternary ammonium groups. Particle size is 5 µm, and column dimensions range from 150 × 2.0 mm to 250 × 4.0 mm. Standard eluents consist of 3.2 mmol/L sodium carbonate and 1.0 mmol/L sodium bicarbonate. Chemical suppression (MSM-LC) or sequential suppression (MSM + MCS) is used, paired with conductivity detection. Operating temperature is typically 25–30 °C and flow rates are 0.18 mL/min (2 mm) or 0.7 mL/min (4 mm). Degassing, CO₂ adsorption and guard columns ensure baseline stability and protect the separation phase.

Main Results and Discussion

Key performance observations include:

• Stable baseline conductivity (< 0.2 nS/cm noise) with standard eluent and suppression
• Retention time shifts as a function of eluent composition, temperature and organic modifiers, enabling method flexibility
• Resolution of seven common anions (F⁻, Cl⁻, NO₂⁻, Br⁻, NO₃⁻, PO₄³⁻, SO₄²⁻) within 10–20 minutes
• Successful adaptation to low-level analyte detection: bromate in potable water, hexavalent chromium (EPA 218.7), trace ions in power-plant coolant, aerosol-derived ions via PILS, denatured bioethanol and UHT milk

Benefits and Practical Applications

The Metrosep A Supp 5 column offers:

• High capacity and selectivity for both monovalent and polyvalent anions
• Wide pH tolerance (3–12) and compatibility with up to 100% organic solvents
• Low pressure drop (≤ 15 MPa for 4 mm, ≤ 20 MPa for 2 mm) and fast equilibration times
• Integrated chip memory enabling method transfer and performance tracking

Applications range from routine drinking water testing to specialized process control in power generation and fuel production.

Future Trends and Possibilities

Emerging developments include:

• Miniaturized columns and ultra-high throughput configurations
• Advanced gradient and multi-dimensional separations for complex matrices
• Integration with high-resolution mass spectrometry for structure elucidation
• Enhanced inline sample preparation (dialysis, preconcentration) for trace-level analysis

Conclusion

The Metrosep A Supp 5 column series delivers reliable, flexible and robust performance for anion chromatography across a wide scope of applications. Following recommended start-up, maintenance and troubleshooting procedures ensures optimal longevity and data quality.

Reference

• Metrohm Application Note S-229: Oxalate, Thiosulfate and Thiocyanate in Amines
• Application Note S-239: Oxyhalides and Standard Anions according to EPA 300.1
• Application Note S-265: Semi-continuous Anion Determination in Aerosol via PILS-IC
• Application Note S-269: Metrohm Intelligent Partial Loop Injection Technique (MiPT)
• Application Note S-275: Formate, Acetate, Oxalate and Molybdate Analysis
• Application Note U-47: Anions in Cooling Lubricant after Inline Dialysis
• Application Note S-103: Five Anions in Infusion Solution Water
• Application Note S-323: Fast IC Drinking Water Analysis Including Fluoride
• Application Note AN S-154: Eleven Anions with High-Pressure Gradient Elution
• Journal Article: Determination of Haloacetic Acids in Chlorinated Drinking Water (J. Water Health, 2014)
• Poster 8.000.6087: Hexavalent Chromium in Drinking Water (Metrohm)
• Journal Article: Optimal Sample Preservation and Analysis of Cr(VI) by HR-IC (Anal. Sci. Methods Instrum., 2012)
• LC-GC Europe May 2010: Sulfur and Halide Combustion IC
• Metrosep A Supp 5 Flyer, 8.107.5003
• Mono­graph: Water Analysis with Metrohm, 8.038.5003
• Metrohm Column Catalog, 8.000.5117