Abstract

The isocratic retention of enantiomers of β-methyl amino acids (β-methyltyrosine, β-methylphenylalanine, β-methyltryptophan and β-methyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) was studied on a teicoplanin-containing chiral stationary phase at different temperatures and at different mobile phase compositions, using the reversed-phase mode. With variation of both mobile phase composition and temperature, almost baseline separations could be achieved for all four enantiomers of sterically hindered amino acids. The retention factors and selectivity factors for the enantiomers of all investigated compounds decreased with increasing temperature. The natural logarithms of the retention factors (ln k) of the investigated compounds depended linearly on the inverse of temperature (1/T). van 't Hoff plots afforded thermodynamic parameters, such as the apparent change in enthalpy (ΔH°), the apparent change in entropy (ΔS°) and the apparent change in Gibbs free energy (ΔG°) for the transfer of analyte from the mobile to the stationary phase. The thermodynamic constants (ΔH°, ΔS°and ΔG°) were calculated in order to promote an understanding of the thermodynamic driving forces for retention in this chromatographic system. Copyright (C) 1998 Elsevier Science B.V.

Department(s)

Chemistry

Comments

National Institutes of Health, Grant B-3/96

Keywords and Phrases

Amino acids; Enantiomer separation; Methyl amino acids; Temperature effects; Thermodynamic parameters

International Standard Serial Number (ISSN)

0021-9673

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Elsevier, All rights reserved.

Publication Date

18 Dec 1998

PubMed ID

9916304

Download

Full Text Link

Included in

Chemistry Commons

Share

 
COinS