半叶马尾藻粗糖中单糖的离子色谱法分析

Determination of Monosaccharides in Sargassum hemiphyllum(Turner) C.Ag.Polysaccharides by Ion Chromatography

以60～80℃的水从半叶马尾藻干粉中提取粗多糖，用Sevage溶剂去蛋白纯化后，将粗多糖用4．0g／L的三氟乙酸在80℃下水解，水解液在CarboPac^TM PA10离子色谱柱（2mmi．d．×250mm）上以14．0mmol／L NaOH溶液为流动相进行分离，以电化学检测器检测半叶马尾藻粗糖水解产生的单糖成分及含量。结果表明，半叶马尾藻粗糖中木糖、半乳糖、阿拉伯糖、葡萄糖、鼠李糖和果糖的含量分别为2200，820，98，4560，358和740mg／kg，加标回收率范围为86．0％～108．0％，检出限范围为5．6—89．6μg／kg。该方法具有灵敏度高、精密度好、样品不需要衍生化处理等优点，适合藻类样品中单糖的分析。

Sargassum hemiphyllum polysaccharides （SHP） was extracted from dry Sargassum hemiphyllum （Turner） C. Ag. powder using 50 - 80 ℃ purified water and then hydrolyzed with 4.0 g/L trifluoroacetic acid at 80 ℃. Without any derivatization reaction, the determination of monosaccharides in SHP was developed by anion-exchange chromatography with pulsed amperometric detection with an Au working electrode and an Ag/AgCl reference electrode. Monosaccharides were separated on a CarboPac^TM PA10 anion-column （2 mm i. d. × 250 mm） by using isocratic elution consisting of 14 mmol/L sodium hydroxide at a flow rate of 0. 20 mL/min. Six monosaccharides, xylose, galactose, arabinose, glucose, rhamnose and fructose, contained in SHP were separated and determined. Their contents in SHP were 2 200, 820, 98, 4 550, 358 and 740 mg/kg, respectively. The recoveries of the six monosaccharides were in the range 85.0%- 108.0%. The detection limits for these monosaccharides ranged from 5.5 to 89.6 μg/kg. The experimental results showed that SHP mainly consisted of xylose and glucose with smaller quantities of galactose, arabinose, rhamnose and fructose. This method is suitable for the determination of monosaccharides without any derivatization reaction at the level of μg/kg in dry algae with high sensitivity and good precision.