氧化淀粉羧基含量的分析方法研究

Research of analysis method for the determination of the carboxyl content of oxidized starch

采用热糊滴定、配位滴定、醋酸钙法3种方法分别测定了淀粉氧化完成时的羧基含量,相对偏差平均值分别为0.18%、1.60%和0.91%,测定时间分别为90、70和85 min。结果表明,热糊滴定法测定的数据精密度和准确度最好,适宜于产品检验;配位滴定法测定时间短,精密度随着高锰酸钾用量的增大而提高。在高锰酸钾质量分数为5%时,精密度和准确度都高于醋酸钙法,适用于产品进厂时的快速检验和定性研究。

Oxidized starch is a versatile chemical raw material that analysis method would be chosen in product quality controlling and testing process.The precision and accuracy of different methods vary significantly.In this paper,the carboxyl content was determined by thermal paste titration,compleximetry and calcium acetate titration.The averages of relative deviation were 0.18%,1.60% and 0.91% measured by the three methods respectively,and the measured time was 90,70 and 85 minutes respectively.The results showed that： the precision and accuracy of thermal paste titration data was the best,being suitable for product testing;the measured time of compleximetry was short,and the precision improved with the increasing amount of potassium permanganate.The precision and accuracy of compleximetry were higher than the calcium acetate method,when the amount of potassium permanganate was 5%.It was suitable for the fast inspection of factory and qualitative research.