Monosaccharide Quantification by Ion Chromatography

Monosaccharide quantification was carried out in a Dionex ICS3000 ion chromatography system (Thermo-Fisher; Waltham, Massachusetts, USA) equipped with a pulsed amperometric detector, a CarboPac PA1 (4 × 250 mm) analytical column, and a CarboPac PA1 (4 × 50 mm) guard column (Thermo-Fisher; Waltham, Massachusetts, USA). Neutral sugar separation was performed at 35°C with a 1 mL min^–1 flow rate using an isocratic gradient of 18 mM NaOH for 27 minutes, followed by a separation of acidic sugars using 105 mM NaOAc and 120 mM NaOH for eight minutes at a 1 mL min^–1 flow rate at 35°C and a wash with 200 mM NaOH for five minutes. The column was equilibrated in 18 mM NaOH for 10 minutes after every step; and standard curves of either neutral sugars (i.e., d-Fuc, l-Rha, l-Ara, d-Gal, d-Glc, d-Xyl, and d-Man) or acidic sugars (i.e., d-GalA and d-GlcA) were used for quantification.