A Zirconia-Nanoparticles-Modified Carbon Paste Electrode for Voltammetric Determination of Ibuprofen

Zirconia-modified carbon paste electrode (ZrO2/CPE) was prepared, characterized, and applied for efficient ibuprofen quantification by differential pulse adsorptive stripping voltammetry. The increased surface area of the modified electrode (up to 74 %), combined with the excellent zirconia adsorption performance allowed a 36 % signal increase to be achieved compared to bare CPE. Under optimized experimental conditions (69 : 1 w % graphite to ZrO2 ratio, 5 min accumulation time, pH 4.5) the ZrO2/CPE exhibited a linear response to ibuprofen in the range from 20 mu mol L-1 to 250 mu mol L-1. The LOD of 4 mu mol L-1 (S/N=3) attained was found to be sufficient to perform ibuprofen analysis in pharmaceutical formulations. The results were validated by ibuprofen determination in commercial tablets with satisfactory recovery values (98.8-102 %). The presence of common pharmaceutical excipients did not affect the ibuprofen voltammetric response. The proposed sensor also demonstrated good reproducibility (RSD=2.84 %) and long term stability.