<p>Sulfanilamide and nitrite have been standardized to each other by diazotization titration; however, no literature was found on determination methods for either material on an absolute basis. In the present study, coulometric titration with electrogenerated bromine was first used to determine sulfanilamide. Coulometric titration provides absolute assays of the amount of substances, based on Faraday’s laws of electrolysis, and also has a high degree of accuracy compared to other instrumental methods. Nitrite was assayed by diazotization titration based on the coulometrically determined sulfanilamide. This idea provides a new methodology for the absolute determination of the purity of basic chemicals whose purity could previously only be assessed in relative terms.</p> Graphical Abstract <p></p>