羧甲基壳聚糖的含量测定

Determine the Single-Sugar Content of Carboxymethylchitosan

羧甲基壳聚糖含量的测定通常采用的方法为乙酰丙酮法，但由于市售羧甲基壳聚糖样品中氨基的的脱乙酰化程度和取代度差异，导致用乙酰丙酮法测定市售样品含量时实测值与理论值偏差较大。因此，采用测还原总糖含量的3，5-二硝基水杨酸比色法（DNS法）对羧甲基壳聚糖进行含量测定。经过方法学验证，该方法线性的平均相关系数r=0．9995，以D-盐酸氨基葡萄糖计线性范围在200-1800μg，重复性实验RSD=1．23％，平均回收率为100．06％，RSD＝2．45％，显色后吸收值在2h内稳定。用DNS法对市售羧甲基壳聚糖样品的含量测定结果与理论含量基本相符。因此，该方法更适用于羧甲基壳聚糖的含量测定。

The assaying of Carboxymethylchitosan is commonly used the acetylacetone methods. However, the market samples always have different substituted degree and deacetylated extent, so the singlesugar content of samples using acetylacetone methods is often largely deviated to the real values. In the article, the result showed that DNS colorimetric method gains the more precise data that are closed to the theoretical content than Elson-Morgan Method. The range of the DNS method is 200-1800 g （r= 0. 999 5） for D-（＋）-Glucosamine hydrochloride at 520 nm. The sensitivity, accuracy and precision of DNS method were high, and the average recollection rate was 100. 06%. Therefore, DNS method is suitable for determining reducing sugar in carboxymethylchitosan.