Abstract: Tea polysaccharide was purified by Sephadex G-100 gel filtration, and its purity and molecular weight (Mw) were determined by high performance gel permeation chromatography (HPGPC). The GPC elution behavior of tea polysaccharide on UltrahydrogelTM 500(7.8×300mm)column was studied by using mobile phase with various concentrations of NaCl. Dextran T- system was found to be unsuitable as Mw calibration standards in GPC because the Mw of tea polysaccharide was changed with the change of ionic concentration in the mobile phase. Thus, the purified tea polysaccharide obtained in this study was standardized to be used instead as the calibration standards for the determination and comparison of tea polysaccharides in tea samples collected from different geographic locations and species varieties. The GPC was run at 35℃on an UltrahydrogelTM 500 column(7.8× 300mm)with a refractive index(RI) detector. Distilled water was used as the mobile phase at a flow rate of 0.6ml/min. The calibration curve was linear over the tea polysaccharide concentration range of 0.604～6.04mg/ml, with a correlation coefficient of r = 0.9997. The tea polysaccharide mass recovery ranged from 80.4% to 93.2% with a RSD of 5.42%. The assay method developed in this paper is found to be simple, reproducible and reliable, and thus ideally suitable for the quality control of tea polysaccharide derived products and raw materials.

Key words: High Performance Gel Permeation Chromatography (HPGPC), tea polysaccharide, determination