Multi-Dimensional HPLC Analysis of Metabolic Related Chiral Amino Acids -Method Development and Biological/Clinical Applications-

Abstract

The existence of D-amino acids in mammals has been increasingly reported, and clarified that D and L enantiomers have different biological functions, distributions and metabolic pathways. Some D-amino acids were also reported to have a correlation with diseases, and the screening of biomarkers based on quantitative enantioselective metabolomics is highly expected. However, the amounts of most D-amino acids, especially the metabolic-related chiral amino acids, are usually at trace levels in biological samples. Therefore, highly selective and sensitive analytical methods are essential for their accurate determination. In this focusing review, multi-dimensional high-performance liquid chromatographic (HPLC) systems for the precise determination of metabolic-related chiral amino acids are introduced with their application to biological samples. For the highly-sensitive determination, target amino acids were precolumn-derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). The multi-dimensional HPLC systems were composed of a reversed-phase column in the 1 st dimension and an enantioselective column in the 2 nd dimension. By using these systems, various proteinogenic amino acids were clearly observed in the tissues and physiological fluids of rodents. The existence of metabolic-related chiral amino acids in various biological samples were also elucidated.

Retention Behavior of Various Aromatic Compounds on Poly(butylene terephthalate) Stationary Phase in Liquid Chromatography

“…In contrast to the numerous number of reports for the selectivity and the phase ordering differences between polymeric and monomeric ODS phases [28][29][30][31][32], however, the systematic understanding and the resulting fundamental theory for the intermolecular interaction between solutes and bonded phase ligands in LC has not been established well. In the LC separation for a particular separation problem, a wide variety of stationary phases has been synthesized and commercialized [9,33], however, there is still a long way to get a universal chemically-bonded stationary phase that could offer a complete separation for real sample matrices within a reasonable analysis time [33][34][35][36][37][38], as typically found in the separation of structural isomers [39]. This is because a complexity in the actual retention process on the bonded phase, where many parameters should be taken into account to systematically understand the retention of particular analyte on the stationary phase.…”

Determination of Chiral Amino Acids in Various Fermented Products Using a Two-Dimensional HPLC-MS/MS System

“…D-Amino acids, the minor stereoisomers of amino acids in the living beings, have been discovered in higher organisms along with the advances in analytical techniques [1][2][3]. In 1986, the presence of non-negligible levels of D-aspartate (Asp) in rodents and humans was reported [4].…”

“…For the determination of the amino acid enantiomers, a variety of chromatographic methods using chiral derivatizing reagents, chiral stationary phases and chiral mobile phases has been reported [2,24]. Among the previously reported analytical techniques, the combination of the reversed-phase separation (the purification of target amino acids as the D plus L mixtures) and the enantioselective separation by a chiral stationary phase (two-dimensional (2D) HPLC analysis) is one of the most sensitive and selective approaches [2,3,[25][26][27][28][29].…”

Identification and Evaluation of Biomarkers for Niemann-Pick Disease Type C Based on Chemical Analysis Techniques

“…Therefore, a combination of derivatization reactions and LC/MS/MS analyses were performed for functional group determination. Acetylation, 7-nitro-2,1,3-benzoxadiazole (NBD) derivatization [103][104][105], and methylation were used for identification of hydroxyl, amino, and carboxylic acid groups, respectively. The theoretical masses of the reacted products were set as precursor ions, and all product ions were observed at m/z 184.…”