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

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.