Development of a Disposable Pencil Graphite Electrode Modified with Poly 1,5-Diaminonaphthalene for Voltammetric Determination of Flufenamic Acid

Abstract

Due to their comparable electrical properties, pencil graphite electrodes (PGE) have become a more popular electrode in electrochemical applications than traditional carbon electrodes, mostly because of their affordability and availability, which allows for disposable applications. Both cyclic voltammetry (CV) and chronoamperometry (CA) techniques were used to develop a new disposable modified pencil graphite electrode based on the electropolymerization of 1,5-diaminonaphthalane (1,5-DAN). Characterization results confirmed that the modified p-1,5-DAN/PGE(CV) sensor showed much enhanced sensitivity and lower resistivity than the bare and p-1,5-DAN/PGE(CA) sensor, therefore, it was used for the sensitive and selective voltammetric determination of flufenamic acid (FFA). Under the optimum experimental conditions, the p-1,5-DAN/PGE(CV) sensor showed limits of detection (LOD) and quantitation (LOQ) of 4.97 × 10−10 (0.14 ng ml−1) and 1.66 × 10−9 M (0.47 ng ml−1), respectively, applying square wave anodic stripping voltammetry method. The p-1,5-DAN/PGE(CV) sensor also exhibits good accuracy, repeatability, storage stability and selectivity for detecting FFA in biological fluids. These results confirms that the developed p-1,5-DAN/PGE(CV) sensor is more sensitive to measuring FFA in biological fluids, pharmaceutical formulations, and pharmacokinetic studies compared with the previous electrochemical sensors.