Square Wave Voltammetric Determination of Ibuprofen at Poly(L-Aspartic Acid) Modified Glassy Carbon Electrode

Abstract

A simple and fast modification of bare glassy carbon electrode (GCE) by electropolymerization of L-aspartic acid (L-Asp) using cyclic voltammetry was reported for the detection of ibuprofen (IBP). The poly(L-Asp)/GCE was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and electroactive surface area measurements. The cyclic voltammetric and square wave voltammetric study of IBP in 0.25-M acetate buffer solution at pH 4 showed an obvious electrocatalytic effect toward IBP oxidation, which resulted in a higher current response and a negative shift in the peak potential, at the polymer film modified electrode compared with the bare GCE. Under the optimized conditions, a calibration curve was obtained by the square wave voltammetry at the poly(L-Asp)/GCE. The square wave voltammetric peak current linearly varied with IBP concentrations in the range of $1.0 \times 10^{-6}$ M to $1.5 \times 10^{-4}$ M with the limit of detection (3S b /m) and the limit of quantification (10S b /m) of $2.2 \times 10^{-7}$ and $7.4 \times 10^{-7}$ M, respectively. The method was successfully applied for the determination of IBP in pharmaceutical formulations and biological samples with satisfactory recovery values, 90%–108%. The proposed sensor also demonstrated good selectivity, repeatability, and reproducibility with appreciable long term stability.