Intermittent counter-current extraction--effect of the key operating parameters on selectivity and throughput

Area of Science:

• Analytical Chemistry
• Separation Science
• Chromatography

Background:

• Intermittent counter-current extraction (ICcE) is a valuable technique for compound separation and concentration.
• Optimizing ICcE parameters is crucial for efficient preparative-scale applications.

Purpose of the Study:

• To evaluate the effectiveness of ICcE for separating a complex model mixture.
• To demonstrate the tunability of ICcE by adjusting phase system polarity and time cycles.
• To identify critical operational parameters for continuous ICcE on a twin-bobbin chromatograph.

Main Methods:

• Separation of a modified GUESSmix model sample using ICcE.
• Utilized a range of HEMWat phase systems from polar (11) to non-polar (23).
• Demonstrated adjustment of the time cycle to control stream splitting.

Main Results:

• Achieved a throughput exceeding 1 kg/day for the model sample at preparative scale.
• Successfully separated the model mixture into two distinct eluant streams.
• Established the necessity of adjusting dead volumes in flying leads for continuous ICcE to maintain hydrodynamic and mechanical balance.

Conclusions:

• ICcE is a high-throughput method suitable for preparative-scale separation of complex mixtures.
• Phase system polarity and time cycle are key parameters for controlling separation outcomes in ICcE.
• Proper instrument configuration, including dead volume adjustment, is essential for stable continuous operation of ICcE.