Fabrication of an Electrochemically Synthesized Nanoporous Gold Electrode for In-Situ Ascorbic Acid Determination in Fruit Samples

In this report, we present the development of a nanoporous gold (NPG) modified electrode fabricated through a mold-assisted electrodeposition technique, wherein a gold film was deposited onto a gold microfiber substrate. This modified electrode was subsequently employed for the in-situ determination of ascorbic acid (AA) in orange and lime juice samples. The NPG-modified electrode exhibited a high edge density, which contributes to an enhanced electrochemically active surface area, promoting a favorable electrocatalytic effect for the anodic oxidation of AA and resulting in a significantly lowered oxidation potential. Differential pulse voltammetry (DPV) measurements revealed a detection limit of 10 µmol L-1 and a quantification limit of 30 µmol L-1. The NPG-modified electrode demonstrated outstanding analytical performance, displaying both high sensitivity and selectivity for AA determination in a complex matrix (orange and lime juice). The voltammetric data were corroborated with coulometric experiments, further validating the reliability of the electrochemical determination of AA using the NPG-modified electrode. Thus, this work highlights the potential of this novel electrochemical sensor, presenting a straightforward and efficient approach for NPG sensor fabrication, and underscoring its substantial promise for in-situ analytical applications.