Enantioselective ion-exclusion chromatography on teicoplanin aglycone and (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid stationary phases.
Ion-exclusion chromatography is a well established technique for the analysis of achiral ionic species, but it has rarely been applied to chiral analytes. In this paper enantioselective ion-exclusion separations were developed on two commercially available HPLC phases: Chirobiotic TAG, based on teicoplanin aglycone, and Opticrown RCA (+), based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. Chirobiotic TAG columns have a carboxylic acid group on the chiral ligand, which can be partially ionized to exclude anionic analytes by ionic repulsion. Under acidic conditions Opticrown columns have a cationic sublayer generated from the aminopropyl base silica that excludes cationic analytes. Both columns demonstrate a large dependence of efficiency on flow-rate, with the highest efficiencies at 0.1 ml/min on a 4.6 mm inner diameter column.
Steffeck
Robert J
RJ
Pharmacia Corporation, 4901 Searle Parkway, Skokie, IL 60077, USA. robert.j.steffeck@pharmacia.com
Zelechonok
Yury
Y
D002853:Chromatography, Liquid / Q000379:methods*; D043844:Crown Ethers; D004988:Ethers, Cyclic / Q000737:chemistry*; D013237:Stereoisomerism; D017334:Teicoplanin / Q000031:analogs & derivatives* / Q000737:chemistry*
D043844:Crown Ethers; D004988:Ethers, Cyclic; C090732:18-crown-6 2,3,11,12-tetracarboxylic acid; D017334:Teicoplanin; C063101:teicoplanin aglycone