General Purification

Astrea Bioseparations Ltd (Astrea) have a range of high performance Ion Exchange and Hydrophobic Interaction Adsorbents which can be used in in combination with our Affinity adsorbents to produce highly pure proteins.

What is Ion Exchange Chromatography?

Ion Exchange (IEX) chromatography is used to separate proteins based on their net charge at a particular pH. A protein is positively charged when the pH is below the pI (isoelectric point) of the protein and is negatively charged when the pH is above the pI of the protein. IEX chromatography separates proteins by a reversible interaction between the charged protein and an oppositely charged adsorbent.

Astrea Bioseparations IEX range includes DEAE, CM, Q and SP adsorbents.

What is Hydrophobic Interaction Chromatography?

Hydrophobic Interaction Chromatography (HIC) is used to separate proteins based on relative hydrophobicity.  Interactions between hydrophobic groups in water are promoted by the presence of water structuring salts, and at high ionic strengths, hydrophobic residues on the surface of a protein associate strongly with other hydrophobic species (the ‘’salting-out’’ effect).  At very high ionic strengths protein precipitation occurs.  However, at intermediate ionic strengths, proteins can be adsorbed from solution onto hydrophobic surfaces.  This adsorption is reversible, and elution is achieved by simply lowering the ionic strength.  Consequently, HIC is particularly useful for the purification from high ionic strength biological extracts since binding is performed in the presence of salt and elution in the absence of salt.  The technique may be applied to the purification of most soluble proteins.

Astrea Bioseparations HIC range includes both Phenyl and Octyl adsorbent.


All the aforementioned products are available in a convenient pre-packed format (1 & 5mL columns), GMP Ready Columns (up to 7L) and loose media up to 10L pack sizes. These adsorbents all use Astrea’s agarose base matrix, PuraBead™ P6HF, a nearly mono-dispersed 6% highly cross-linked agarose.

Key features of PuraBead™ P6HF:

  • Excellent flow properties
  • High dynamic binding capacity
  • Robust and long life adsorbent
  • Sanitizable using Sodium Hydroxide
  • Easy to pack
  • Manufactured to ISO9001 accredited standard
  • Single batches produced of up to 1000 litres
  • Supported with a comprehensive Regulatory Support File (includes leachables and extractables)