Ion exchange chromatography selection guide
To find the media or prepacked columns that suit your needs, choose the option below that best describes your application.
Ion exchange chromatography

Screen ion exchange media which will work with my protein

Isolate, concentrate, and stabilize my unpurified protein

Remove bulk impurities from my partially purified protein

Analyse or remove trace impurities or closely-related substances from my almost pure protein

If isoelectric point (pI) of the target protein is known:

  • Select an anion exchanger (Q, DEAE, ANX) with a buffer pH above the pI.
  • Select a cation exchanger (S, SP, CM) with a buffer pH below the pI.

If pI of the target protein is unknown:

  • Test for selectivity using a strong ion exchanger, Q, S or SP. Strong ion exchangers maintain their charge over a wider pH range than weak ion exchangers and are suitable for most applications.
  • Strong and weak ion exchangers refer to the extent that the ionization state of the functional groups varies with pH.
  • Strong and weak do not refer to the strength with which the functional groups bind to proteins.

Strong ion exchangers:

  • Use when work is to be performed over a broad pH range.
  • Use when maximum resolution occurs at an extreme pH.

Weak ion exchangers:

  • Ion exchange capacity varies with pH.
  • Use when the selectivity of the strong ion exchanger is unsatisfactory.
Anion exchangers Functional group
Quaternary ammonium (Q), strong -O-CH2N+(CH3)3
Diethylaminoethyl (DEAE), weak -O-CH2CH2N+H(CH2CH3)2
Diethylaminopropyl (ANX), weak -O-CH2CHOHCH2N+H(CH2CH3)2
Cation exchangers Functional group
Sulfopropyl (SP), strong -O-CH2CHOHCH2OCH2CH2CH2SO3–
Methyl sulfonate (S), strong -O-CH2CHOHCH2OCH2CHOHCH2SO3–
Carboxymethyl (CM), weak -O-CH2COO–