Highly sensitive electrochemical sensing of ascorbic acid (vitamin C) using Pd-doped MnO2 supported on carbon quantum dots (Pd-MnO2@CQD) in water and fruit juices

Abstract

The Pd-MnO<inf>2</inf> nanoparticles attached to carbon quantum dots nanocomposite were synthesized using the green synthesis and hydrothermal process. Characterization of the as-prepared nanocomposite was intensively performed by FT-IR, powder XRD, XPS, and HR-TEM analysis. The synthesized nanomaterial was further examined for its selective and sensitive ascorbic acid (ASA) sensing using a Pd-MnO<inf>2</inf>@CQD modified glassy carbon electrode (GCE). The Pd-MnO<inf>2</inf>@CQD nanocomposite exhibits a distinct and improved peak current of ASA when compared to electrodes treated with Pd-MnO<inf>2</inf> and bare GCE. The designed sensor has excellent performance, with a linear range of 10–1500 μM, a low detection limit of 0.14 μM (S/N = 3), a high sensitivity of 1.9671 μAµM−1 cm−2. Furthermore, the constructed sensor demonstrates good sensitivity for detecting ASA in a variety of real samples. © The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry 2025.