壳寡糖是壳聚糖经降解后的低聚物，其相对分子质量较小，水溶性好，易于吸收，生物活性高。本实验采用过氧化氢氧化降解脱乙酰度高于95%的壳聚糖，利用离子色谱-脉冲安培法对低聚合度的壳寡糖进行定性和定量分析，以制备聚合度在6以下的壳寡糖。以降解产物的离子色谱中聚合度6以下的峰面积和与产物得率之积作为响应指标，并结合凝胶渗透色谱来考察过氧化氢浓度、反应时间、反应温度对壳聚糖降解的影响及降解特性，并利用响应面分析法对氧化条件进行优化。研究结果表明，采用离子色谱测定聚合度6以下的壳寡糖在方法学上是可行的，具有良好的精密度、稳定性和重现性。得到的最佳降解工艺条件为：过氧化氢浓度4.50%、反应时间6 h、反应温度56 ℃。由最优条件下的降解产物离子色谱图可知，聚合度越低的壳寡糖越容易得到；可利用离子色谱法对壳聚糖的降解过程进行调控。

Chitooligosaccharides can be obtained by chitosan (COS) degradation. Chitooligosaccharides have a low molecular weight, good water solubility, and high biological activity, and can be easily absorbed. In this work, Chitosan with a deacetylation degree of over 95% underwent oxidative degradation by hydrogen peroxide to prepare chitooligosaccharides with a degree of polymerization below six, which was qualitatively and quantitatively analyzed by ion chromatography and pulsed amperometric detection. The effect and degradation characteristics of hydrogen peroxide concentration, reaction time, and reaction temperature on chitosan degradation were investigated using gel permeation chromatography and using the product of the total peak area of chitooligosaccharides in the ion chromatogram of the degradation products and the yield of products as the response index. In addition, the oxidation conditions were optimized by a response surface analysis method. The results showed that in terms of methodology, it was feasible to use ion chromatography to determine chitooligosaccharides, and the method had good precision, stability, and reproducibility. The optimum degradation conditions were as follows: hydrogen peroxide concentration 4.50%, reaction time 6 h, and reaction temperature 56 ℃. From the chromatographic analysis of the degradation products under optimal conditions, the chitooligosaccharides with a lower degree of polymerization were easier to obtain, and the degradation process of chitosan could be controlled by ion chromatography.

广东省科技计划项目（2013B090800033、2013B090600129、2014A010107007）