"Determination of zinc ion content in zinc-containing curing activator by potentiometric titration"

Abstract

Using Na2EDTA solution as titrant, copper ion-selective electrode as indicator electrode, Ag/AgCl electrode as reference electrode, zinc ion content in zinc-containing curing activator was determined by potentiometric titration. The results showed that the addition of copper sulfate solution could increase the titration-jump of zinc ion titration curve and copper ion-selective electrode was sensitive in buffer system with pH value 10. The contents and recovery rates of zinc ions in two kinds of zinc-containing curing activators were determined by potentiometric titration and compared with atomic emission spectrometry. The results showed that the recovery rates of zinc ions in the two kinds of curing activators were 100.13% and 99.32% respectively, and there was no significant difference in accuracy and precision between the two methods. Content of zinc ion in standard solution was determined by potentiometric titration method and verified statistically. The results showed that there was no significant difference between the test value and standard value, indicating that using potentiometric titration method to determine the zinc content in the zinc-containing curing activator was feasible and effective. At the same time, the contents of zinc ion in mixed rubbers were determined, which were similar to the theoretical calculation value. Therefore, the method was also suitable for the determination of zinc ion content in mixed rubber.

Keywords

• zinc-containing curing activator， zinc ion content， potentiometric titration， copper ion- selective electrode，