Revisiting resolution in hydrodynamic countercurrent chromatography: tubing bore effect

Area of Science:

• Chromatography
• Separation Science
• Analytical Chemistry

Background:

• Countercurrent chromatography (CCC) relies on a support-free biphasic liquid system.
• Retaining the liquid stationary phase (Sf) within the CCC column is a key challenge.
• Available CCC systems include hydrostatic (centrifugal partition chromatographs, CPC) and hydrodynamic designs.

Purpose of the Study:

• To investigate the influence of tubing bore size on stationary phase retention and CCC efficiency.
• To determine the optimal tubing bore for various solute partition coefficients and mobile phase flow rates.
• To evaluate the impact of tubing bore on experiment duration and separation performance.

Main Methods:

• Theoretical analysis of stationary phase retention in coiled CCC tubes.
• Examination of the relationship between tubing bore, column volume, and efficiency.
• Modeling the influence of tubing bore on solute resolution and retention times.

Main Results:

• Larger bore tubing retains more stationary phase compared to smaller bore tubing.
• An optimal tubing bore size exists, dependent on solute partition coefficient and mobile phase flow rate.
• Larger tubing bores significantly reduce experiment durations for all solutes, especially hydrophobic ones in reversed-phase CCC.

Conclusions:

• Tubing bore size is a critical parameter for optimizing CCC performance.
• Larger bore tubing offers advantages in stationary phase retention and faster separations.
• This study provides theoretical insights for improving CCC efficiency and reducing analysis time.