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Differences in retention behavior between small and large molecules in ion-exchange chromatography and reversed-phase chromatography

1984; Elsevier BV; Volume: 142; Issue: 1 Linguagem: Inglês

10.1016/0003-2697(84)90527-x

1096-0309

Björn Ekström, Gunilla Jacobson,

Chromatography in Natural Products

The retention (k′) for various biomolecules was studied as a function of the mobile phase composition in reversed-phase chromatography (RPC) and ion-exchange chromatography (IEC). The “elution window” (EW) for a molecule is defined as the mobile phase composition in which 1 <k′ < 10. The following relations were verified: (i) EW(RPC) < EW(IEC), and (ii) EW(large Mr) < EW(small Mr). The results support the theory that in both RPC and IEC larger molecules interact with the stationary phase by multiple-site binding. The results are used to explain why, in both RPC and IEC, larger molecules are best separated on short columns using gradient elution while smaller molecules often require longer columns and isocratic conditions.