Online comprehensive two-dimensional ion chromatography × capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Accurate quantification of inorganic anions and organic acids in water is crucial for environmental monitoring and public health.
• Existing analytical methods may face challenges in resolving complex mixtures of these analytes.

Purpose of the Study:

• To develop and validate a comprehensively coupled online two-dimensional ion chromatography-capillary electrophoresis (IC × CE) system.
• To enable high-resolution quantitative analysis of inorganic anions and organic acids in water samples.

Main Methods:

• An in-house built sequential injection-capillary electrophoresis instrument was coupled with a nonfocusing modulation interface.
• High field strength (+2 kV/cm) was utilized for rapid second-dimension separations.
• The system was optimized for comprehensive sampling of the IC effluent.

Main Results:

• The IC × CE system successfully resolved haloacetic acids, dalapon, and common inorganic anions.
• Achieved a two-dimensional peak capacity of 498 with a peak production rate of 9 peaks/min.
• Demonstrated linear calibration curves for analytes from 5 to 225 ng/mL and good recoveries (69-119%) in spiked tap water.

Conclusions:

• The developed online IC × CE system offers a powerful tool for the quantitative analysis of diverse water contaminants.
• This method provides high peak capacity and efficient separation for complex aqueous matrices.
• The approach is suitable for analyzing trace levels of organic acids and inorganic anions in real-world water samples.