Analysis of diflunisal by electrochemical methods

A new differential pulse polarographic (DPP) and differential pulse adsorptive stripping voltammetric (DPAdSV) methods for the electrochemical behavior and quantitative determination of diflunisal were described. In these voltammetric methods, the peak potential of diflunisal was round as -0.31 V (vs. Ag/AgCl) with selected Britton-Robinson buffer (BR, pH 7.8) as a supporting electrolyte. The variation of the peak current with the concentration of diflunisal were linear in the 9.0-40.0 and 4.0-30.0 mug ml(-1) concentration ranges for DPP and DPAdSV methods, respectively. The limits of detection (LOD) were found as 5.0 and 0.1 mug ml(-1) for DPP and DPAdSV methods, respectively. The developed methods were validated by evaluation of the validation parameters. The characteristics of the peak current of diflunisal were examined in detail and the results proved that the peak current has an adsorption characteristic. The developed methods were proposed for rapid determination of diflunisal in commercial tablets. The recovery studies showed that developed assays had a good accuracy and precision with mean recoveries 99.92 and 100.02% and mean variation coefficients 0.29 and 0.24% in DPP and DPAdSV methods, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.