Electrochemical Performance of pH Sensor Based on LbL Films of Polyaniline-Gum Arabic Nanocomposite and Graphene Oxide

Abstract

Miniaturized pH sensors have attracted the attention mostly due to their applications for monitoring chemical and biological processes. The modification of electrodes by Layer-by-Layer (LbL) technique results in films with nanometric structure for application in devices with different sizes. In this paper, an electrode modified with LbL films of polyaniline-gum Arabic nanocomposite (PANI-GA) and graphene oxide (GO), designed (PANI-GA/GO)3, was applied as a potentiometric pH sensor based on states of oxidation PANI. The pH measurements were performed in BR buffer solution and a linear range was observed from pH 2 to 7. The detection limit (DL) and quantification limit (QL) were of pH = 0.465 and 1.55, respectively. Analytical curves were obtained in triplicate and inter-assay precision was calculated for the system, demonstrating good results with relative standard deviation (RSD) of 3.7% for five measurements in different days. The (PANI-GA/GO)3 LbL film showed promising results for its use in the development of potentiometric pH sensor.