Enantioseparation of Organic Acids and Monosaccharides by Novel Ligand Exchange-Capillary Electrophoresis

Amino alcohol‐derived chiral stationary phases

“…126 Most chiral ligands used in the CLE-CE are amino acids or their derivatives except for an amino alcohol, (S)-3-amino-1,2-propanediol. 127 First, covalently bonded ligand exchange CSPs prepared by amino alcohols were reported by Yuki et al 70,71 Two diastereomeric amino alcohols, (1R,2S)-and (1S,2S)-2-amino-1,2-diphenylethanol, were converted to (1R,2S)and (1S,2S)-2-carboxymethylamino-1,2-diphenylethanol by treating them with ethyl bromoacetate and then with 1 M NaOH solution. Then, (1R,2S)-and (1S,2S)-2-carboxymethylamino-1,2-diphenylethanol were prepared and treated with 3-glycidoxypropyl silica gel, which was obtained from a reaction between the 3-glycidoxypropyltrimethoxysilane and silica gel, to yield two covalently bonded diastereomeric CSPs 4 and 5.…”

“…81 (S)-3-amino-1,2-propanediol borate complex was used as a chiral selector for the enantioseparation of monosaccharides in ligand-exchange capillary electrophoresis. 127 The amino alcohol-based diastereomeric Pirkle-type and ligand exchange CSPs are summarized in Table 1.…”

“…Among these diastereomeric CPSs, DPEDA-based CSP was commercialized as "ULMO" and showed impressive chiral resolutions. 20,[127][128][129][130] The diastereomeric chiral compounds, such as (R,R)-DPEDA, (1R,2R)-ADPE, and (1S,2R)-ADPE, were used as the starting materials to prepare three N-DNB derivative CSPs (CSPs 45-47), and three C3 symmetric CSPs (CSPs 48-50) are shown in Figure 6.…”

“…A recent review paper also analyzed and reported chiral ligand exchange capillary electrophoresis (CLE‐CE) 126 . Most chiral ligands used in the CLE‐CE are amino acids or their derivatives except for an amino alcohol, (S)‐3‐amino‐1,2‐propanediol 127 …”

Some thoughts about enantioseparations in capillary electrophoresis

“…Both l and d sugars taste sweet although l ‐sugars commonly do not produce calories in the living body. Kodama and co‐workers used a ligand‐exchange method based on CE for separation of monosaccharide enantiomers, as well as enantiomers of small chiral organic acids .…”