CROWNPAK® CR(+) and CR(-) contain a chiral crown ether as a chiral selector, which is coated onto a 5 µm silica support. CROWNPAK® selectors are mainly used to separate chiral amino acids and other small molecules with primary amine groups. The elution order of the enantiomers can be reversed when necessary.

Acidic mobile phases such as perchloric acid (pH 1 to 2), are used to operate these columns under standard conditions. To shorten the retention time of hydrophobic samples, the addition of methanol (15% maximum v/v) has been shown to be effective for CROWNPAK® CR(+) and CR(-).