MECC Determination of Monosaccharide Composition of Polysaccharides in Camellia and Liupu Teas

The polysaccharides in teas were obtained by ultrasonic assisted extraction. After purified, the polysaccharides were hydrolyzed to become monosaccharides with 2 mol·L^-1 sulfuric acid. Their derivatives were obtained after monosaccharides reacted with 1-phenyl-3-methyl-5-pyrazolone, and determined by micellar electrokinetic capillary chromatography (MECC). The optimized electrophoresis conditions were as follows: the buffer solution was 40 mmol·L^-1 Na₂B₄O₇-20 mmol·L^-1 SDS with pH 10, separation voltage was 10 kV, injection height was 10 cm, and injection time was 10 s. Linearity ranges for 8 monosaccharides were kept in the same range of 10.0-180 mg·L^-1, with values of detection limits (3S/N) in the range of 4.87-8.32 mg·L^-1. Values of RSDs (n=5) ranged from 3.0% to 7.5%. Test for recovery was made by standard addition method, giving results in the range of 98.0%-105%. Monosaccharide composition of polysaccharides in both camellia and liupu tea were arabinose, glucose, rhamnose, galactose, mannose and galacturonic acid. The ratio of the amount of substance was 0.29：0.02：0.10：0.06：0.42：0.35 for Camellia, and 0.13：0.19：0.09：0.05：0.16：0.03 for Liupu tea.