A simple spectrophotometric method for the determination of cerium(iv)‎ and phenothiazines through the exploitation of their redox coupled ion -pair complexes malledevarapura devappa gowtham, mansour said abdul galil, mahadevaiah

الملخص EN

A simple, accurate and highly stable spectrophotometric method for the determination of four phenothiazines as well as for cerium (IV) is described.

The method is based on the oxidation of phenothiazines by cerium (IV) in hydrochloric acid medium producing the radical cations, [Ph] + which upon associate with CeCl4-to form ion–pairs, [Ph] + [CeCl4] -, providing an exceptional color stability to the system.

The main advantage of the method is that one can determine either phenothiazines using cerium (IV) or cerium (IV) using phenothiazines.

The novelty of the new method lies in overcoming a series of shortcomings of the earlier literature methods and in stabilization of color of the phenothiazine radical cations via ion–pair formation.

The method is found to be effective either for the determination of the phenothiazines or cerium (IV) as indicated by the analytical data obtained from the analysis of pure compounds, some phenothiazine pharmaceutical formulations and simulated cerium (IV) alloys and also cerium (IV) present in rare earth carbonates.

Therefore, the new method could be considered either as a parallel or a complementary one to the existing official methods for the determination of the phenothiazines or cerium (IV).