巴戟天寡糖中果糖的测定方法

Analysis of fructose in Morinda officinalis oligosaccharide

目的研究巴戟天寡糖中果糖的分析方法。方法采用4种不同条件对巴戟天寡糖进行酸水解,然后分别采用薄层色谱法(TLC)、凝胶过滤色谱法(GPC)和毛细管电泳法(CE)分析酸水解产物。结果 TLC和GPC方法分析表明,2 mol/L三氟乙酸(TFA)-120℃-2 h条件水解巴戟天寡糖后无法获得原型果糖,0.01 mol/L TFA-40℃-10 h条件无法使寡糖水解完全,0.5 mol/L TFA-40℃-2 h和0.05 mol/L TFA-40℃-10 h两种水解条件可使寡糖水解完全,得到果糖和葡萄糖。CE法进一步分析表明,0.05 mol/L TFA-40℃-10 h为最佳酸水解条件,经测定,巴戟天寡糖在该条件下酸水解后果糖与葡萄糖的单糖摩尔比为10∶1。结论本研究提示,强酸水解和还原反应不适于巴戟天寡糖和多糖中的果糖分析,应采用温和酸水解条件,而CE可用于单糖组成分析。

Objective To determin fructose in Morinda officinalis oligosaccharides(MOOP). Methods Four conditions were used for acid hydrolysis of MOOP and the products of acid hydrolysis were analyzed using thin-layer chromatography(TLC),gel permeation chromatography(GPC)and capillary electrophoresis(CE). Results Results from TLC and GPC showed that no fructose was produced by acid hydrolysis of MOOP under the condition of 2 mol/L TFA-120℃-2 h,and an uncompleted hydrolysis of MOOP was found under the condition of 0.01 mol/L TFA-40℃-10 h. Fructose was obtained under the two acid hydrolysis conditions of 0.5 mol/L TFA-40℃-2 h and 0.05 mol/L TFA-40℃-10 h). Among them,0.05 mol/L TFA-40℃-10 h was the better acid hydrolysis condition for MOOP according the CE analytical results,which showed the molar ratio of fructose and glucose was 10∶1. Conclusion The study suggested that strong acid and reduction reaction were not suitable for fructose analysis in MOOP or polysaccharides,while the mild acidic condition coupled with the capillary electrophoresis was suitable for the analysis of monosaccharide composition.