An electrochemical sensor based on a carbon paste electrode modified with lanthanum nanocomposites for gallic acid determination in fruit juice samples

• Published in: Materials chemistry and physics 2025-02, Vol.332, Article 130313
• Main Authors: Achache, Mohamed, El-Haddar, Sanae, El Haddaoui, Hajar, Idrissi, Ghizlane Elouilali, Draoui, Khalid, Bouchta, Dounia, Choukairi, Mohamed
• Format: Article
• Language: English
• Subjects: Carbon paste electrode; Electrochemical detection; Food analysis; Gallic acid; Lanthanum nanocomposite
• ISSN: 0254-0584
• DOI: 10.1016/j.matchemphys.2024.130313

The detection of gallic acid (GA) is essential due to its antioxidant properties, particularly in the food industry. Despite various methods for GA analysis, developing a simple, fast, and practical sensor remains challenging. In this study, a sensitive and selective sensor was designed by modifying a carbon paste electrode with a lanthanum nanocomposite (LaOOH/CPE) for GA detection. The nanocomposite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), and zeta potential (ζ-potential) analysis. The electrochemical properties were assessed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The LaOOH/CPE exhibited excellent electrocatalytic performance for GA oxidation in BRB solution (pH 2.0), with well-defined signals. Kinetic parameters, including a charge transfer coefficient of 0.407 and a standard electron transfer rate constant of 1.06 s−1, were determined. Differential pulse voltammetry (DPV) revealed a linear GA detection range of 0.5 μM–30 μM, with a detection limit of 0.07 μM. The sensor demonstrated high sensitivity (7.389 μA cm−2 μM−1), good repeatability (RSD 1.1 %), reproducibility (RSD 1.4 %), and stability (RSD