▎ 摘　　要

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. (c) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.