Voltammetric determination of verapamil and propranolol using a glassy carbon electrode modified with functionalized multiwalled carbon nanotubes within a poly (allylamine hydrochloride) film

In this report, we describe the individual determination of verapamil (VPM) and propranolol (PROP) in pharmaceutical formulations using square-wave adsorptive anodic stripping voltammetry (SWAdASV), differential-pulse adsorptive anodic stripping voltammetry (DPAdASV), and a glassy carbon electrode modified with functionalized multiwalled carbon nanotubes within a poly (allylamine hydrochloride) film. The anodic peak potential for VPM and PROP at this modified electrode was 1.09 V and 0.930 V (versus Ag/AgCI (3.0 mol L-1 KCI)), respectively, in a 0.25 mol L-1 H2SO4 solution. Under optimized SWAdASV and DPAdASV conditions, the obtained analytical curves were linear for VPM concentrations ranging from 5.0 x 10(-9) to 1.1 x 10(-7) mol L-1, and PROP concentrations ranging from 7.4 x 10(-8) to 1.0 x 10(-6) mol L-1, with detection limits of 3.6 x 10(-9) mol L-1 and 2.6 x 10(-8) mol L-1, respectively. Both of the proposed methods were successfully applied for the individual determination of VPM and PROP in several pharmaceutical formulations. The results were in a close agreement with a 95% confidence level for those obtained using official spectrophotometric methods. (C) 2013 Elsevier B.V. All rights reserved.