Solvent systems for countercurrent chromatography: an aqueous two phase liquid system based on a room temperature...

Area of Science:

• Separation Science
• Green Chemistry
• Biotechnology

Background:

• Aqueous two-phase systems (ATPS) are widely used for bioseparation.
• Traditional ATPS often employ polyethylene glycol (PEG), which can have limitations in phase retention and solute discrimination.
• Ionic liquids (ILs) offer tunable properties for novel ATPS development.

Purpose of the Study:

• To investigate a new aqueous two-phase system based on the ionic liquid 1-butyl-3-methyl imidazolium chloride (BMIM Cl), potassium dibasic phosphate (K(2)HPO(4)), and water.
• To compare the performance of this IL-based ATPS with classical PEG-based ATPS in terms of phase diagram, liquid phase retention in countercurrent chromatography (CCC), and solute partitioning.
• To evaluate the polarity, hydrophobicity, and discrimination factor of the IL-based ATPS.

Main Methods:

• Preparation and determination of the full phase diagram of the BMIM Cl/K(2)HPO(4)/water ATPS.
• Comparison with PEG 1000 and PEG 10000 based ATPS.
• Evaluation of liquid phase retention in hydrostatic Sanki and J-type hydrodynamic CCC columns.
• Partitioning studies of protein (ovalbumin) and alcohol solutes to assess polarity and hydrophobicity.

Main Results:

• The BMIM Cl ATPS exhibited significantly easier liquid phase retention in both CCC columns compared to PEG 1000 ATPS.
• The BMIM Cl ATPS demonstrated a distinctly different polarity compared to PEG 1000 ATPS, evidenced by differential solute partitioning (e.g., ovalbumin K(D)=180 vs. K(D)=1.4).
• The IL-based system showed a three-fold higher discrimination factor and ten-fold lower intrinsic hydrophobicity than the PEG 1000 ATPS.

Conclusions:

• The novel BMIM Cl-based ATPS offers superior performance in CCC liquid phase retention.
• This IL-ATPS possesses unique physicochemical properties, including different polarity and hydrophobicity, making it advantageous for specific separation tasks.
• The BMIM Cl ATPS represents a promising alternative to conventional PEG-based systems for efficient bioseparations.