A simple approach to predict device-specific peak widths in countercurrent chromatography

Area of Science:

• Analytical Chemistry
• Separation Science
• Chromatography

Background:

• Countercurrent chromatography (CCC) is a preparative-scale liquid-liquid separation technique.
• Peak width prediction in CCC is crucial for optimizing separation efficiency.
• The probabilistic model for immiscible phase separations and extractions (ProMISE) offers a theoretical framework for peak width calculation.

Purpose of the Study:

• To develop a straightforward method for predicting device-specific peak widths in CCC.
• To experimentally determine the efficiency factor (f’) within the ProMISE model for specific CCC devices.
• To validate the predictive capability of the ProMISE model with experimentally derived device-specific factors.

Main Methods:

• Utilized the ProMISE model to calculate peak widths as a function of the efficiency factor (f’).
• Experimentally determined the factor f’ by analyzing CCC runs of alkylresorcinols on a QuikPrep MK8 device.
• Systematically adjusted the f’ value in ProMISE2 software to match simulated and experimental peak widths.
• Extended the method to previously published data from a CCC-1000 device using alkyl hydroxybenzoates.

Main Results:

• An efficiency factor (f’) of 0.026 was determined for the QuikPrep MK8 device, specific to the experimental conditions.
• The validated factor f’ = 0.026 accurately predicted peak widths for various substance classes and solvent systems on the QuikPrep MK8.
• An efficiency factor (f’) of 0.12 was identified for the CCC-1000 device when separating alkyl hydroxybenzoates.
• The method requires a stable solvent system with no stationary phase loss during the CCC run.

Conclusions:

• The ProMISE model, combined with experimentally determined device-specific efficiency factors (f’), enables accurate prediction of CCC peak widths.
• The determined factor f’ is device-specific, allowing for tailored predictions for different CCC instruments.
• The study provides a practical approach for optimizing CCC separations and enhancing analytical predictability.
• A recommended solvent system (n-hexane/ethyl acetate/methanol/water, 9:1:9:1 v/v/v/v) and analytes are suggested for determining f’ on other CCC instruments if standard applications are unstable.