Abstract: A method for the determination of total acid number in jet fuel by potentiometric titration is presented. The adding mode of titrant and the determination of endpoint were studied by T50 potentiometric titrator. The effect of nonaqueous electrode and carbon dioxide on the experimental results was analyzed, and the optimal testing conditions were determined. The results of potentiometric titration were compared with those of indicator method, and its deviation was less than the reproducibility limit of indicator method. Repeatability of potentiometric titration was satisfied with Grubbs. Results showed that potentiometric titration was suitable to measure the total acid number of jet fuel, potentiometric titration was more accurate than indicator method especially for measuring colored and low acidic samples.

Key words: potentiometric titration, adding mode, total acid number, analytical method