用FTIR测定邻苯二甲酰化壳聚糖的取代度

摘要

The FTIR spectrometry was used to determining the total degree of substitution(DS1) ofphthaloyl chitosans(PHCS) and degree of ubstitution of phthaloyl imide groups (DS2). The probebands, reference bands and baselines in IR spectra were investigated for the determination. The DSswere also determined by 1H NMR andelemental analysis for comparison. Based on the average rela-tive deviations of (Aprobe band/Aref band) to DS in FTIR spectra the most suitable APB/ARB) was found to beA1 12BL1/A1391BL3 for DS1 calculation, and A1 775BL1/A1 654BL1 for DS2, where BL1, BL2 and BL3 are thebaselines in IR spectra(Fig. 1).%从壳聚糖合成了不同取代度的邻苯二甲酰化壳聚糖作为标样，标样的取代度由1H NMR和元素分析确定.研究以FTIR作为工具测定此系列衍生物的总取代度(DS1)和环状酰亚胺取代的取代度(DS2)的方法.吸光度用基线法得到.对不同探针谱带，参比谱带和基线的多种组合进行了比较，并通过(A探针／A参比)／DS的平均相对偏差找出最佳组合.结果表明对该系列衍生物，测定DS1最合适的A探针／A参比是A1712BL1／A1391BL3，测定DS2最合适的A探针/A参比是17751/A1654BL1.这两种组合的工作曲线斜率分别为2.45和1.20，这2个工作曲线只适用于脱乙酰度为84％的壳聚糖.但对DS2，A1775Bl1／A146BL1可适用于全范围脱乙酰度的壳聚糖，其工作曲线的斜率为2.63.