华南理工大学学报(自然科学版) ›› 2011, Vol. 39 ›› Issue (1): 58-62.doi: 10.3969/j.issn.1000-565X.2011.01.011

• 化学化工 • 上一篇    下一篇

高取代度CMC取代度的紫外光谱法快速测定

叶君1,2 张燕兴1,3 熊犍2   

  1. 1.华南理工大学制浆造纸工程国家重点实验室,广东广州510640;2.华南理工大学轻工与食品学院,广东广州510640;3.广东省造纸研究所,广东广州51030
  • 收稿日期:2010-05-12 修回日期:2010-06-21 出版日期:2011-01-25 发布日期:2010-12-01
  • 通信作者: 熊犍(1965一),男,博士,教授,主要从事纤维素及其它天然高分子物质结构与性能的研究 E-mail:lcjxiong@scut.edu.cn
  • 作者简介:叶君(1963一),女,博士,教授,主要从事植物资源化学研究
  • 基金资助:

    国家“973”计划项目(2010CB732201);国家自然科学基金资助项目(51043011)

UV-Based Rapid Determination of Degree of Substitution of CMC with High Substitution

Ye Jun1,2 Zhang Yan-xing1,3 Xiong Jian2   

  1. 1. The south China university of technology of the pulp and paper engineering state key laboratory, guangdong guangzhou 510640; 2. South China university of technology, light industry and food institute, guangdong guangzhou 510640; 3. Guangdong paper institute, guangdong guangzhou 51030
  • Received:2010-05-12 Revised:2010-06-21 Online:2011-01-25 Published:2010-12-01
  • Contact: 熊犍(1965一),男,博士,教授,主要从事纤维素及其它天然高分子物质结构与性能的研究 E-mail:lcjxiong@scut.edu.cn
  • About author:叶君(1963一),女,博士,教授,主要从事植物资源化学研究
  • Supported by:

    国家“973”计划项目(2010CB732201);国家自然科学基金资助项目(51043011)

摘要: 研究了高取代度的羧甲基纤维素(CMC)取代度的紫外光谱测定方法.首先利用CMC与Cu(Ⅱ)反应,得到CMC-Cu(Ⅱ)溶液的紫外吸光值随稀硫酸铜溶液体积的变化曲线,发现该曲线可划分为3个区,其中Ⅰ区是CMC链上的羧基与Cu(Ⅱ)离子按照化学计量反应生成配合物的区域,且符合Lambert-Beer定律.将Ⅰ区曲线拟合得到一条直线,当相关系数达0.990时,可通过该曲线与拟合直线的吸光值最大处交点所对应的硫酸铜溶液体积计算得到CMC的取代度.该方法对于取代度大于0.80的CMC具有高的取代度测量准确性,测定结果与国标方法误差在1.7%~3.5%之间,且具有样品用量少、简单、快速的特点.

关键词: 羧甲基纤维素, 取代度, Cu(Ⅱ)离子, 紫外光谱法

Abstract:

Proposed in this paper is a UV-based method to rapidly determine the degree of substitution(DS) of carboxymethyl cellulose(CMC) with high substitution.In this method,a curve of the UV absorbance of CMC-Cu(Ⅱ) solution versus the volume of dilute copper sulfate solution is obtained via the reaction CMC and Cu(Ⅱ),which is divided into three regions,of which regionⅠ defined by Lambert-Beer's law corresponds to the stoichiometrical reaction of the carboxyl groups on CMC chain with Cu(Ⅱ) ions.Then,by fitting the curve in region Ⅰ,a straight line is obtained.When the square of correlation coefficient is more than 0.990,the DS of CMC can be calculated according to the volume of dilute copper sulfate solution at the intersection with maximum absorbance.The proposed method,which is of the advantages of rapidity,simplicity and is of small quantity of sample involved,is accurate in determining the DS of CMC with a DS higher than 0.80.As compared with the national standard method,the error of the proposed method ranges from 1.7% to 3.5% only.

Key words: carboxymethyl cellulose, degree of substitution, Cu(Ⅱ) ions, UV spectrophotometry