Monosaccharide-NAIM derivatives for D-, L-configurational analysis

Abstract

The D-, L-enantiomeric pairs of common monosaccharides (xylose, ribose, rhamnose, arabinose, fucose, glucose, mannose, galactose, N-acetylgalactosamine, glucuronic acid and galacturonic acid) were derivatized with 2,3-naphthalenediamine to form the corresponding D-, L-aldo-NAIM derivatives. A simple and facile capillary electrophoretic method was established for sugar composition analysis by simultaneously determining the migration times of these aldo-NAIMs using borate buffer at high pH (100 mM, pH 9.0). The methodology is also applicable to sialic acid (ketose monosaccharides). The quantitation level of the proposed method was in the 10~500 ppm range and the LOD was 1 ppm. The enantioseparation of D, L pairs of aldo-NAIMs were also achieved by using modified sulfated-α-cyclodextrin as the chiral selector in phosphate buffer (300 mM, pH 3.0). In addition, the combination by reductive amination of amino-aldo-NAIM agent and D-, L-enantiomeric pairs of monosaccharides formed a diastereomeric pair for saccharide configuration analysis. Aldo-NAIM derivatives are thus shown to be rapid and efficient agents for analyzing saccharide compositions and configurations with good linearity and short analysis times via capillary electrophoresis.

Figure 1

The Fisher projection of D-, L-glucose.

Figure 2

Electrophorogram of 2,3-naphthalene diamine derived monosaccharides. Peaks: 1= Rha-NAIM; 2= GalNAc-NAIM; 3= SA-NAQ (sialic acid-naphthyl benzo[g]-quinoxaline); 4= Xyl-NAIM; 5= Rib-NAIM; 6= Glc-NAIM; 7= Man-NAIM; 8= Ara-NAIM; 9= Fuc-NAIM; 10= Gal-NAIM; 11= GlcA-NAIM; 12= GalA-NAIM. Conditions: buffer, 100 mM borate (pH 9.0); applied voltage, 12 kV; uncoated fused-silica capillary, 30 cm × 50 μm I.D.; sample injection, 3s by pressure 0.5 psi; wavelength, 254 nm.

Scheme 1

The preparation of D-, L-polyol-NAIMs by a domino reaction of aldose-aromatic ortho-diamine (2,3-naphthalene diamine) condensation.

Figure 3

Chiral resolution of seven enantiomeric pairs of naphthalenediamine derivated monosaccharides.

Figure 4

Simultaneously analysis sugar composition and its D-, L-configuration in one inject. Enantioseparation condition was set as phosphate−sulfated−α−CD system with a 30/40.2 cm × 50 µm uncoated fused-silica capillary. (NaH₂PO₄, 300 mM, pH 3.0, sulfated−α−CD, 10 mg/mL at 15 kV).

Scheme 2

Synthesis of D-, L-arabino-(pentahydroxy)-hexyl-D-N-glucosamino-NAIM diastereomers.

Figure 5

Effects of pH value of borate buffer on derivated monosaccharides separation. (A) pH 8.0 (B) pH 9.0 (C) pH 10.0. Peaks: 1= Rha-NAIM; 2= GalNAc-NAIM; 3= SA-NAQ; 4= Xyl-NAIM; 5= Rib-NAIM; 6= Glc-NAIM; 7= Man-NAIM; 8= Ara-NAIM; 9= Fuc-NAIM; 10= Gal-NAIM; 11= GlcA-NAIM; 12= GalA-NAIM. An uncoated fused-silica capillary (30/40.2 cm × 50 μm) with borate buffer (100 mM), applied voltage (12 kV), separation temperature (25 °C) and 40 ppm samples were used.

Figure 6

Effects of concentration of borate buffer on derivated monosaccharides separation. (A) 50 mM (B) 100 mM (C) 200 mM. Peaks: 1= Rha-NAIM; 2= GalNAc-NAIM; 3= SA-NAQ; 4= Xyl-NAIM; 5= Rib-NAIM; 6= Glc-NAIM; 7= Man-NAIM; 8= Ara-NAIM; 9= Fuc-NAIM; 10= Gal-NAIM; 11= GlcA-NAIM; 12= GalA-NAIM. An uncoated fused-silica capillary (30/40.2 cm × 50 μm) with borate buffer (pH 9.0), applied voltage (12 kV), separation temperature (25 °C) and 40 ppm samples were used.