Crownpak CR(-) 5µm 150x4.0mm HPLC Column

The CROWNPAK CR(-) HPLC column 150x4.0mm, 5µm; it is not based on amylose or cellulose, but on a chiral crown ether selector on silica. The specific modification used is (R)-18-Crown-6-ether; the phase is coated. CROWNPAK CR(-) is used for reverse-phase HPLC under acidic mobile phase conditions and achieves separation via complex formation between crown ether and the protonated amino group. Typical applications of the CROWNPAK CR(-) include amino acids, primary amines and enantiomers, where a reversed-order elution sequence is required. CROWNPAK CR(-) is the enantiomeric counterpart to CROWNPAK CR(+) and can specifically reverse the elution order.

Features and Benefits

• Chiral crown ether phases for amino acids and primary amines
• Coated CR variants for established reverse-phase methods under acidic conditions
• Immobilized CR-I variants with expanded solvent flexibility
• Complementary (+) and (-) selectors for altering the elution order
• Suitable for free amino acids, small primary amines, and polar chiral molecules

Additional Notes

CROWNPAK phases are not amylose- or cellulose-based polysaccharide phases. Enantiomeric recognition occurs through complex formation between a chiral crown ether and protonated amino groups, typically under acidic mobile phase conditions. In the coated CROWNPAK CR phases, the crown ether is immobilized on silica. This design offers proven selectivity for amino acids and primary amines but is significantly more sensitive to organic modifiers and widely varying solvent conditions. CROWNPAK CR-I uses immobilized crown ether selectors. The advantage lies in greater solvent flexibility and robustness; the disadvantage is that methods from the coated CR series should not be transferred without testing, as immobilization and the solvent environment can influence selectivity.

Legal Notices

CROWNPAK is a registered trademark of the manufacturer Daicel Corporation, Osaka, Japan.