Maleopimaric acid anhydride-bonded silica monolith as chiral stationary phase for separations of phenylthiocarbamyl amino acids by CEC.

A new type of chiral silica monolith was successfully developed for the enantioseparation of phenylthiocarbamyl amino acids (PTC-(D/L)-AAs) by CEC. The bare monolithic silica column was prepared by a sol-gel process and has been modified chemically with aminopropyltrimethoxysilane, followed by immobilization of a chiral selector maleopimaric acid anhydride. Eight pairs of tested amino acids enantiomers including PTC-(D/L)-arginine, PTC-(D/L)-valine, PTC-(D/L)-leucine, PTC-(D/L)-4-methylphenylalanine, PTC-(D/L)-phenylalanine, PTC-(D/L)-beta-phenylalanine, PTC-(D/L)-tryptophan and PTC-(D/L)-kynurenine were well resolved with high column efficiencies. The influences of organic modifier in mobile phase on apparent retention factor, enantioselectivity factor and resolution were also investigated.