Spectral and cyclic voltammetric investigation of oxidized products of 10-[4 '-(N-diethylamino)butyl]-2-chlorophenoxazine and its applications in redox titrimetry

10-[4'-(N-diethylamino)butyl]-2-chlorophenoxazine (DBCP) undergoes a revers ible one-electron oxidation with cerium (IV) to form a pink coloured radica l cation [DBCP+.] in the presence of stoichiometric amounts [DBCP: Ce(IV)= 1:1] of the reactants. The radical cation underwent a second one-electron o xidation to form a brownish yellow coloured dication [DBCP2+] in the presen ce of more than one equivalent of cerium(IV), which was characterized by UV -vis, IR and mass spectrometry. The cyclic voltammogram of DBCP exhibited t wo anodic waves at 721 mV and 1158 mV and two cathodic waves at 653 mV and 1076 mV at a scan rate of 24 mV/s. The peak at 721 mV corresponds to the ox idation of DBCP to the radical cation [DBCP+.] and the second anodic peak a t 1158 mV stands for the oxidation of the radical cation to the dication [D BCP2+]. Bromine oxidizes DBCP to three products as evidenced by HPLC and th e tentatively predicted structures based on the mass-spectral data support the formation of brominated oxidized products. In order to explore the anal ytical applications, the optimum conditions for the successful use of DBCP as a redox indicator in the macro and micro estimation of ascorbic acid, me thionine, isoniazid, phenylhydrazine hydrochloride and biotin using chloram ine-B as oxidant, have been developed. The indicator gives sharp and stoich iometric end-points.