Multi-modal CSPs

The macrocyclic glycopeptides CSPs arc capable of operating in three different mobile phase systems reversed phase, normal phase, and the new polar organic mode. The new polar organic mode refers to the approach when methanol is used as the mobile phase with small amounts of acid and/or base as the modifier to control 

The enantioselectivity of the macrocyclic CSPs are different in each of the operating modes, probably because of different separation mechanisms functioning in the different solvent modes. The possible chiral recognition mechanisms for three mobile phase compositions on glycopeptide phases are listed in Table 2-3 in descending order of strength. 

Statistically, of the compounds enantioresolved by macrocyclic glycopeptide CSPs, new polar organic mode accounts for more than 40 %, balanced by reversed-phase mode, while typical normal-phase operation resulted in approximately 5 % of separations. Some categories of racemic compounds that are resolved on the glycopeptide CSPs at different operating modes are listed in Table 2-4. 

Hydrogen bonding 7C-7C interaetion Dipole staeking Sterie interaetion 

New polar (Cyelie) Amines Amino aleohols (a-Hydroxyl/halogen) aeids 

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