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Retention behavior of a homologous series and positional isomers of aliphatic amino acids in hydrophilic interaction chromatography
Author(s) -
Douša Michal,
Srbek Jan,
Stránský Zdeněk,
Gibala Petr,
Nováková Lucie
Publication year - 2014
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201301348
Subject(s) - chemistry , homologous series , amino acid , hydrophilic interaction chromatography , chromatography , derivatization , structural isomer , elution , partition coefficient , high performance liquid chromatography , stereochemistry , organic chemistry , biochemistry
The retention behavior of several series of free α‐ and ω‐amino acids and positional isomers of amino pentanoic acid in the hydrophilic interaction chromatography mode (HILIC) was studied. The study was carried out on three stationary phases followed by post‐column derivatization with fluorescence detection in order to describe the retention mechanism of the tested amino acids. The effect of chromatographic conditions including acetonitrile content in the mobile phase, mobile phase pH (ranging from 3.5 to 6.5) and concentration of buffer in the mobile phase was investigated. The effect of the number of carbon atoms ( n C ) in aliphatic chains of the individual homologue of α‐ and ω‐amino acids and the logarithm of the partition coefficient (log D ) on retention was also a part of the presented study. A good correlation ( r > 0.98) between the log k and log D values of amino acids or n C , respectively, was observed. The described linear relationships were subsequently applied to predict the retention behavior of individual members of the homologous series of amino acids and to optimize the mobile phase composition in HILIC. The obtained results confirmed that the retention mechanism of α‐amino acids, ω‐amino acids and positional isomers of amino acids was based on the log D values and the number of carbon atoms in the aliphatic chains of amino acids. The elution order of ω‐amino acids and positional isomers of amino pentanoic acid was strongly dependent on the mobile phase pH in the investigated range whereas the retention factors of all α‐amino acids remained essentially unchanged on all tested stationary phases.