CROWNPAK® CR(+) / CR(−) columns       

(R)-18-crown-6-ether coated on a silica support

These columns contain a chiral crown ether as a chiral selector which is a coated onto a 5μm silica support. Acidic mobile phases such as Perchloric acid pH 1 to 2, are used to operate these columns under standard conditions. Note that to shorten the retention time of hydrophobic samples, the addition of Methanol ( 15% maximum v/v) has been shown to be effective. These columns are the reference columns for achieving amino acid separations, with the advantage that the elution order of the enantiomers can be reversed when necessary ( CR(-) column gives the reversed elution order compared to CR(+) column).