Related Experiment Video
Updated: Jun 28, 2026

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices
Published on: March 27, 2019
Determination of sulfate ion by potentiometric back-titration using sodium tetrakis (4-fluorophenyl) borate as a
1Department of Chemical Science and Engineering, Ariake National College of Technology, Omuta, Fukuoka 836-8585, Japan.
Abstract:
A potentiometric back-titration method for the determination of sulfate ions using a plasticized poly(vinyl chloride) membrane electrode sensitive to a titrant is described. The method is based on ion association between the excess of 2-aminoperimidinium added to the sulfate ion in the sample and sodium tetrakis (4-fluorophenyl) borate (FPB) in the titrant. The titration end-point was detected as a sharp potential change due to an increase in the concentration of the free FPB at the equivalence point. The end-point was detected even in the presence of a 20-fold excess of common cations and anions relative to the concentration of the sulfate ion within approximately 2% of titration error. A linear relationship between the concentration of the sulfate ion and the end-point volume of the titrant exists in the sulfate ion concentration range from 2x10(-4) to 3x10(-3) mol l(-1) using 10(-2) mol l(-1) FPB solutions as the titrant. The present method could be applied to determine sulfate ions in sea water.
Related Concept Videos
Potentiometric Titration: Overview
Titration of Polyprotic Base with a Strong Acid
Precipitation Titration: Endpoint Detection Methods
In the Volhard method, a standard excess of AgNO3 is first added to the...
Titration of Polyprotic Acids with a Strong Base
EDTA: Indirect and Alkalimetric Titration
Titration of a Polyprotic Acid

