N-substituted phenothiazines as redox indicators in bromatometry.

Diethazine hydrochloride, butaperazine dimaleate, trifluoperazine hydrochloride, promethazine hydrochloride, prochlorperazine maleate and chlorpromazine hydrochloride have been studied as indicators in bromate titration of quinol, metol and ascorbic acid. They give a very sharp reversible colour change at the equivalence point. Their formal potentials have been determined. A simple but accurate method for the estimation of quinol and metol is reported.