Determination of mercaptopyrimidines with copper(II) in acetonitrile.

A non-aqueous oxidimetric method is described for the determination of mercaptopyrimidines with copper(II) perchlorate in acetonitrile, diphenylamine being used as indicator. A bright platinum wire is used as indicator electrode and a modified calomel or an antimony electrode as reference for potentiometric titrations. The method, based on the oxidation of the mercapto group to the disulphide, is simple, accurate and reliable.