Abstract
The electrochemical behavior of a biologically important phenazine derivative, 1-methoxyphenazine (MPZ) was scrutinized over a pH range 1.2-12.8 by cyclic, square wave and differential pulse voltammetry. The results of cathodic peak potential shift as a function of pH demonstrated that 1-methoxy phenazine is reduced by a 1e(-), 1H(+) diffusion controlled process. E-pc - E-pc/2 values, scan rate dependent deviation of peak potential, heterogeneous electron transfer rate constant and inequality of the components of total current proved the quasi-reversible nature of the redox process. MPZ was found to oxidize in the pH range 5-12.8 by the loss of a single electron without proton involvement. The pK(a) of MPZ with a value of 11.2 was determined from the intersection of the two segments of E-p vs. pH plot. The pK(a) values of MPZ obtained from all the three electrochemical techniques were found in very good agreement. The limits of detection and quantification of 1-methoxyphenazine were determined as 2.6 mu M and 8.6 mu M respectively. On the basis of the results obtained redox mechanism was proposed with the objective of emphasizing imperative aspects of structure-activity relationships and understanding the unexplored pathways by which this class of compounds exert its biochemical actions. (C) 2013 The Electrochemical Society. All rights reserved.