Introduction to bonded chiral phases

• Bonded phases - Introduction
• Bonded phases - Mechanical and chemical stability
• Bonded phases - Loadability
• Coated phases - Introduction
• Coated phases - Mechanical stability
• Coated phases - Performance stability
• Coated phases - Loadability

Kromasil bonded chiral phases: a network of chiral polymers covalently bonded to the Kromasil silica matrix

The silica

Kromasil chiral stationary phases for HPLC, SFC and SMB are based on the well-known Kromasil premium spherical silica. The surface properties of the silica have a great impact on the selectivity of the chiral phases.

The chiral polymer

Two phases have been developed to complement each other in selectivity:

• Kromasil Chiral DMB

  : The chiral monomer is O,O'-bis (3,5-dimethylbenzoyl)-N,N'-diallyl-L-tartar diamide.

• Kromasil Chiral TBB

  : The chiral monomer is O,O'-bis (4-tert-butylbenzoyl)-N,N'-diallyl-L-tartar diamide.

The chiral monomers are reacted with a multifunctional hydrosilane yielding a network polymer incorporating the bifunctional C2-symmetric chiral selector (figure 1).

The chiral stationary phases

The chiral polymer is covalently bonded to functionalized Kromasil silica, as seen in figure 2.

Fig. 1 - Chiral polymer synthesis.

Fig. 2 - The binding of the chiral polymer to the Kromasil silica.

Performance

“Chiral network polymers covalently bonded to Kroamsil silica to be used with all solvents in HPLC, SFC and SMB/MCC.”

Kromasil Chiral separate a broad range of racemates (see separate application brochure). The phases are based on 5 μm, 10 μm or 16 μm particles for best efficiency. The small particles are necessary for difficult separations and give sharp peaks in analytical separations.

For preparative scale, 10 μm or 16 μm particles are ideal, giving high efficiency and relatively low pressure drop in large diameter columns. The best selectivity is obtained under normal phase conditions. The phases are however stable also under reversed phase conditions.

Kromasil chiral stationary phases are patented by Eka Chemicals AB and manufactured according to ISO 9001.