Determination of the enantiomers of α-H-α-amino acids, α-alkyl-α-amino acids and the corresponding acid amides by high-performance liquid chromatography

✍ Scribed by A. Duchateau; M. Crombach; J. Kamphuis; W.H.J. Boesten; H.E. Schoemaker; E.M. Meijer

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 526 KB
• Volume: 471
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(00)94174-8

✦ Synopsis

o-Phthalaldehyde in combination with N-acetyl-L-cysteine is a useful derivatization reagent for the optical resolution of enantiomeric a-H-a-amino acids, a-alkyl-a-amino acids and the corresponding acid amides. By using reversed-phase high-performance liquid chromatography with a mobile phase containing copper(I1) acetate and L-proline, the diastereomeric derivatives of the a-amino compounds can be separated under isocratic conditions. The rate of reaction of a-alkyl-a-amino compounds with o-phthalaldehyde-N-acetyl-L-cysteine can be increased by selectively increasing the amount of o-phthalaldehyde in the reaction mixture. When the derivatization parameters were controlled automatically, the derivatization process showed good reproducibility and the method was found to be suitable for quantitative measurements. The method was applied to monitor the enantiomeric purity of a-H-a-amino acids and a-alkyl-a-amino acids obtained by enantioselective hydrolysis of the corresponding acid amides using an aminopeptidase.