Constant-Current Coulometry Studies for Assay of Primary Reference Materials to Develop Standards for Titrimetric Analysis

Coulometry is a primary method for measuring the amount of substance of high-purity compounds and its solutions. Coulometric titration is used to determine the purity of primary reference materials for acid/base, precipitation, redox and complexometric titrations. This work aims at presenting the primary system of coulometry from Inmetro, which was used for the characterization of hydrochloric acid solutions from nominal values of 1.0 mol·kg−1 and 0.01 mol·kg−1, as well as the preliminary studies and the results of the key comparison CCQM-K48, which Inmetro has recently participated to determine the purity of potassium chloride (KCl).The reference materials characterized by the Inmetro’s primary system of coulometry will be used to guarantee the traceability and reliability to the measurement results from titrimetric analysis carried out by the Brazilian chemical analysis laboratories. 1