Analytical Sciences

Simultaneous Enantioseparation of Monosaccharides Derivatized with L-Tryptophan by Reversed Phase HPLC

Mami AKABANE,*1 Atsushi YAMAMOTO,*2 Sen-ichi AIZAWA,*3 Atsushi TAGA,*4 and Shuji KODAMA*1

*1 School of Science, Tokai University, 4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
*2 Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan
*3 Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan
*4 Faculty of Pharmacy, Kinki University, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan

Three reducing monosaccharides (glucose; Glc, galactose; Gal, and mannose; Man) were derivatized with L-tryptophan (L-Trp) under alkaline conditions. The DL-Gal and DL-Man derivatives were chirally resolved by HPLC with an acidic mobile phase, but the DL-Glc derivative was not. All of the three DL-monosaccharide derivatives were simultaneously enantioseparated using HPLC with a SunShell RP-AQUA column (C28) and a basic mobile phase. The optimum mobile phase conditions consisted of 5 mM phosphate and 25 mM tetraborate buffer (pH 9.6) at 20°C. With this system, resolution of D- and L-isomers of the Glc, Gal and Man derivatives were approximately 1.7, 2.2 and 2.4, respectively. When the three monosaccarides were derivatized with L-phenylalanine instead of L-Trp, DL-Gal and DL-Man were enantioseparated under both acidic and basic conditions, but DL-Glc was not. It was observed that enantiomer elution orders of the three monosaccharides derivatized with L-Trp were reasonably reversed when derivatized with D-Trp. It was also revealed that borate anions were required for simultaneous enantioseparation with HPLC.

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