羧甲基纤维素钠取代度的测定方法研究

Determination of the degree of substitution of carboxymethyl cellulose sodium

目的比较灰化法和酸度计法两种检测方法的结果,确定羧甲基纤维素钠取代度的最佳检测法方法。方法分别采用灰化法、酸度计法检测同一样品的取代度,分析比较结果。结果灰化法结果其取代度相对标准偏差(RSD%)为0.7%,表明该方法具有良好的精密度;酸度计法结果随放置时间的增加,其取代度呈明显上升的趋势,未能发现明显的突跃点,无法判断其结果,此外,该方法对于不同称样量所测定出的结果不稳定。结论酸度计法虽操作简便,但是存在放置时间、溶解程度等干扰因素,结果不稳定;灰化法虽然操作费时,但结果准确,数据稳定,是测量羧甲基纤维素钠取代度的最佳方法。

Objective To determine the best test method of substitution degree of carboxymethyl cellulose sodium by comparison of the results of ashing method and acidity meter method. Methods The substitution degree of the same samples were detected by ashing method and acidity meter method respectively, and comparing results were analyzed. Results The results determined by ashing method showed the relative standard deviation (RSD%) of substitution degree was 0.7%, and the method had a good precision. The results determined by acidity meter method showed that with the increase of mixing time, the degree of substitution rose obviously, and significant abrupt point was failed to find, so that the result couldn't be judged. In addition, the method was unstable for the determination of samples with different weight. Conclusion Acidity meter method is easy to operate, but there are interference factors such as time, degree of dissolution, leading to unstable results. Ashing method was time-consuming operation, but the results are accurate, stable, so it is the best way to measure the substitution degree of carboxymethyl cellulose sodium.