Synthesis and performance of ferrocene-bonded chiral stationary phase for RP-HPLC

The preparation, characterization and potential liquid chromatographic applications of a ferrocene-bonded chiral stationary phase are presented. The phase was prepared by covalent bonding of ferrocene-derivatized alanine to aminopropylated spherical silica gel. Use of the new stationary phase enabled good separations of phenylalanine, tryptophane, clenbuterol hydrochloride and thioctic acid under reversed-phase conditions within acceptable analysis times (i.e., below 20 min). The separation factors ranged between 1.07 and 1.41 and the resolutions were in no case less than 0.9. The mechanism of retention on the new stationary phase involves strong π-π interaction with each one of the cyclopentadienyl (Cp) groups of the ferrocene and simultaneously hydrogen bonding interactions between the chiral stationary phase and the analytes. The phase enables effective separation of optical isomers with a benzene ring.