脱乙酰甲壳质脱乙酰度测定方法

THE METHOD FOR DETERMINATION OF DEGREE OF DEACETYLATION OF CHITOSAN

脱乙酰甲壳质的脱乙酰度测定有多种方法,本文较详细地介绍了在我们工作中采用过的氢溴酸盐法、电位滴定法、指示剂酸碱滴定法和红外光谱法。根据对红外光谱法的研究结果,指出了由于酰胺Ⅱ1500cm^(-1+峰受样品含水量的影响不大,因而 A_(1550)/A_(2867),A_(1550)/A_(1420)和 A_(1550)/A_(1387)对脱乙酰度的关系均可得到线性关系,特别是 A_(1550)/A_(1420)对脱乙酰度的线性关系更适合于作为脱乙酰度的测定。此外,文中还简要介绍了胶体滴定法,苦味酸法,水杨醛法,紫外光谱及紫外光谱—阶导数法,气相色谱法,凝胶渗透色谱法,园二色性测定法,热解分析法等测定脱乙酰度的方法,并对上述各种方法进行了简单的讨论。

There are many methods for determination of degree of deacetylation(or N-acetylation) of chitosan.This paper describes in detail HBr salt method,titration method and IR spectroscopy method which were used in our research work.According to our experimental results obtained by using IR spectroscopy,amide Ⅱ 1550cm^(-1) band is less affected by the presence of small amounts of adsorbed water of samples and the linear relation of A_(1550)/A_(2867),A_(1550)/A_(1420) and A_(1550)/A_(1378) Vs.degree of deacetylatio can all be obtained so we consider that amide Ⅱ 1550cm^(-)1 band is more adptable to the determination of degree of deacetylation especially of the linear relation of A_(1550)/A_(1420) V_S.degree of deacetylation.In addition,other methods for determination of degree of deacetylation such as colloid titration method,picric acid method, chitosan react with salicylaldehyde method,UV spectrophotometry method, first-derivative UV spectrophotometry method,pyrolysis-gas chomatography,gel permeation chromatography,c.d.measurements method and thermal analysis are also described and discussed briefly in this paper.