牛膝多糖衍生物的几种取代度测定方法的探讨

在研究多糖的结构与功能关系时 ,多糖经化学修饰后 ,其取代基的多少和取代位置均对活性有重要的影响 ,因此对于离子型牛膝多糖衍生物和非离子型牛膝多糖衍生物 ,如何准确测定其取代度非常重要。通过运用酸碱滴定法 (ABT)、原子吸收光谱法 (AAS)、傅立叶变换红外光谱法 (FTIR)和高效液相色谱法(HPLC)相对照分别对羧甲基牛膝多糖 (CM Abps)和羟乙基牛膝多糖 (HE Abps)的取代度进行测定 ,实验结果发现在DS <1.0范围内 ,测得CM Abps的几组数值均比较接近 ,且线性关系较好 ;在DS <2 .0范围内 ,测得HE Abps的几组数值均比较接近 ,线性关系也较好。研究表明 ,运用ABT、AAS、FTIR和FTIR相对照测定CM Abps和HE Abps的取代度是切实可行的 ,而且方法快速简捷 ,精确度和重现性较好。

MEASUREMENT ON THE DEGREE OF SUBSTITUTION OF POLYSACCHARIDE DERIVATIVES FROM ACHYRANTHES BIDENTATA

It is important to determine the degree of substitution (DS) of both ionic Achyranthes bidentata polysaccharide derivatives and nonionic Achyranthes bidentata polysaccharide deriva- tives.The degree of substitution of carboxymethylated Achyranthes bidentata polysaccharides (CM-Abps) and hydroxyethylated Achyranthes bidentata polysaccharides (HE-Abps) were studied using acid-base titration (ABT),atomic absorption spectroscopy (AAS),Fourier transform infrared spectroscopy (FTIR) and HPLC analysis.For CM-Abps,linear relationships in the range of DS<1.0 were obtained by ABT,AAS and IR.And for HE-Abps,linear relationships in the range of DS<2.0 were also obtained by IR and HPLC.The methods are feasible,rapid and concise.Their precision and repeatability are excellent.