Separation of saccharides using fullerene-bonded silica monolithic columns via π interactions in liquid chromatography

Abstract

We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH-π and/or OH-π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC-mass spectrometry with nonlabeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide-fullerene was formed through CH-π and/or OH-π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipoleinduced dipole interaction was dominant, and that maltose-with the higher dipole moment-was more strongly retained compared to other disaccharides having lower dipole moment.

Rim Binding of Cyclodextrins in Size-Sensitive Guest Recognition

“…Figure e shows γ-CD on a large NT of an 8.5 Å apex, much larger than the cavity size of 5 Å, and we assign an RB mode. Hydroxy/π interactions have been reported for the fullerene/saccharide interaction . In Figure g, we illustrate an example of the oB mode, binding on the side wall where we see α-CD as a trapezoid.…”

“…Hydroxy/π interactions have been reported for the fullerene/ saccharide interaction. 33 In Figure 2g, we illustrate an example of the oB mode, binding on the side wall where we see α-CD as a trapezoid.…”

Studies on π Interactions in Liquid-Phase Separations

“…Thus, the development of separation techniques for glycans, which have more branched structures than nucleic acids and proteins, as well as diverse conformations and linkage styles, is still a difficult issue. We reported the separation of saccharides using C60/C70-coated columns with effective CH/OH-π interactions [61]. Computer simulations also supported strong interactions between the fullerenes and the saccharides (Fig.…”

CH−π Interactions in Glycan Recognition

“…The dipole moment of the disaccharide had a dramatic influence on retention times, highlighting the electronic nature of the CH−π interactions. 102 Monosaccharides unable to place a continuous patch of three electropositive protons in contact with an aromatic ring, such as α-mannose or α-glucose, are very poor CH−π donors. 40,93,97 Likewise, many furanosides appear to be weak CH−π donors due to their flexibility and poor geometric complementarity with aromatic groups.…”

“…This importance of geometry is highlighted by Kobayashi et al in their purification of glucose-based disaccharides on fullerene-based columns. The dipole moment of the disaccharide had a dramatic influence on retention times, highlighting the electronic nature of the CH−π interactions …”