Capillary Ion Chromatography with On-Line High-Pressure Electrodialytic NaOH Eluent Production and Gradient...

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Capillary chromatography offers high efficiency but often requires complex setups.
• Developing cost-effective and high-performance systems remains a challenge in analytical chemistry.

Purpose of the Study:

• To describe a small, inexpensive system for high-performance suppressed anion chromatography on a capillary scale.
• To demonstrate superior chromatographic performance using in-house packed capillary columns.

Main Methods:

• A computer-controlled syringe pump system capable of delivering precise flow rates up to 1000 psi.
• In-house packing of fused-silica capillary columns (180 μm i.d.) with commercial stationary phases.
• Utilizing a novel electrodialytic sodium hydroxide (NaOH) eluent generator on the high-pressure side of the pump.

Main Results:

• The capillary system achieved significantly higher efficiencies compared to commercial 2 mm bore columns.
• The system operated effectively at low pressure drops (<800 psi) and flow rates (2 μL/min).
• The eluent generator produced NaOH solutions with excellent purity, supporting both isocratic and gradient elution up to 100 mM.

Conclusions:

• The developed system provides a cost-effective solution for high-performance capillary anion chromatography.
• In-house packed capillary columns offer superior separation efficiency.
• The novel eluent generator simplifies operation and enhances eluent quality for suppressed anion chromatography.