CHIRALPAK® QN-AX and CHIRALPAK® QD-AX are enantioselective weak anion-exchange (AX) HPLC columns. The chiral selectors for CHIRALPAK® QD-AX and CHIRALPAK® QN-AX anion exchange phases are based on complementary quinine (QN) and quinidine (QD) derivative selectors bonded to high efficiency 5 µm diameter spherical silica. The structure of these selectors is such that a tertiary amine is located in a three-dimensional cleft surrounded by additional hydrogen binding sites and a large aromatic group. This combination provides excellent separations of chiral acids.

These columns can be used in reversed phase (RP) mode or in polar organic mode (non aqueous, polar organic solvents containing organic acids and bases as buffer constituents). In addition, the separation of chiral basic and neutral compounds may also be possible, but usually under normal phase (NP) conditions.