Separation of enantiomers on chiral stationary phase based on chicken α1-acid glycoprotein: Effect of silica particle diameters on column performance

• Chicken α1-acid glycoprotein-based silica particle column for enantioseparations.
• Effect of silica particle diameters on the column performance.
• Highest resolution and lowest column efficiency with 2.1-μm silica particles.

The effects of silica particle diameters on performances of chicken α1-acid glycoprotein (c-AGP)-immobilized silica particle columns were investigated. c-AGP was immobilized onto aminopropyl silica particles, whose nominal particle diameters were 5, 3 and 2.1 μm, activated with N,N′-disuccinimidyl carbonate. The retention factor (k), enantioseparation factor (α), resolution (Rs) and height equivalent to a theoretical plate (H) of solutes on three c-AGP columns were evaluated using a mixture of phosphate buffer and organic modifier as a mobile phase in LC. There were not so much differences in their k and α values among three c-AGP columns, while their Rs values were in the order of 2.1 μm > 3 μm > 5 μm silica particles and their H values were in the reversed order. Since three c-AGP columns gave almost the same enantioseparation factors for solutes, their highest Rs and lowest H values on a c-AGP-immobilized column prepared with 2.1-μm silica particles came from its highest column efficiency among there c-AGP columns. These results suggest that 2.1-μm silica particles could be useful for the preparation of c-AGP- or protein-based CSPs.