Continuous Ion Chromatography Module

Significance of the Topic

Automating the production of hydroxide eluents addresses common challenges in ion chromatography, including labor-intensive manual preparation, high chemical consumption, safety risks, and variability in results. The Continuous IC Module offers a sustainable, reproducible, and cost-effective approach, vital for high-throughput environmental, industrial, and research laboratories.

Goals and Overview of the Study

This application note evaluates the 948 Continuous IC Module for on-demand generation of high-purity hydroxide eluents. Key objectives include assessing baseline noise, detection limits, compliance with international standards, and applicability to isocratic and gradient methods, as well as complex, hyphenated analyses.

Methodology

The system generates hydroxide eluents by electrolyzing ultrapure water fed with a refillable concentrate (LiOH, NaOH, or KOH at ≥4 M). An integrated anion trap removes impurities and carbonate, followed by a high-pressure degasser to eliminate H₂. Eluents are optionally processed through a suppressor module for CO₂ removal and sequential suppression before conductivity detection. Performance tests used Metrosep A Supp columns under isocratic and gradient conditions with generated KOH gradients, monitoring baseline stability, linearity, and signal-to-noise ratios.

Instrumentation

• 948 Continuous IC Module, CEP
• Eluent Producer Cartridge A
• Continuous Anion Trap (CT-A)
• High-Pressure Degasser (H-DEG)
• MSM-HC Rotor A for hydroxide eluents
• Metrosep A Supp 19-150/4.0 and A Supp 21-250/4.0 columns
• 4 M potassium hydroxide concentrate

Main Results and Discussion

Automated eluent generation achieved an ultra-low baseline and minimal noise, enabling detection limits consistent with EPA 300.1 Parts A and B, ISO 10304-1/4, and EPA 557. Isocratic separations of major anions at 1 mg/L and gradient analyses for oxyhalides showed sharp, reproducible peaks. Integration with mass spectrometry for haloacetic acid determination demonstrated enhanced accuracy and ease of use.

Benefits and Practical Applications

• Elimination of manual eluent preparation, reducing labor and error
• Lower chemical usage and waste for greener operation
• Continuous, reagent-free operation supports 24/7 analysis
• Enhanced reproducibility and analytical accuracy
• Full compliance with major regulatory standards
• Scalable solution for both routine and method development workflows

Future Trends and Applications

Future developments may include deeper integration with mass spectrometers and other detectors for emerging contaminants, advances in membrane and cartridge design to further reduce detection limits, and more compact, user-centric modules for field and decentralized testing. Growing emphasis on green analytical chemistry will drive continued innovation in in-line eluent generation.

Conclusion

The 948 Continuous IC Module delivers reliable, high-purity hydroxide eluents with exceptional baseline stability and low detection limits. Its automation and sustainability benefits make it an ideal choice for modern ion chromatography workflows across environmental, industrial, and research applications.