Preparation and application of a new modified liquid chromatographic chiral stationary phase based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid

As an effort to improve the chiral recognition efficiency of a previously reported chiral stationary phase (CSP) based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic acid, a new CSP was prepared by simply replacing the amide N–H hydrogens of the tethering groups of the old CSP with methyl groups. The new CSP was superior to the old one in the resolution of racemic primary amines. However, in the resolution of α-amino acids and amino alcohols, the new and the old CSPs were complementary with each other. The elution orders on the new CSP were sometimes opposite to those on the old one. Consequently, the chiral recognition mechanism on the new CSP was presumed to be different from that on the old one. The chiral recognition behavior of the new CSP were investigated with four selected analytes and found to be dependent to some extent on the content of organic and acidic modifiers in aqueous mobile phase and the column temperature.