A flexible and self-supported nanoporous gold wire electrode with a seamless structure for electrochemical ascorbic acid sensor

A flexible and self-supported nanoporous gold (S/NP-Au) has been produced using a simple, green, and quick approach for the electrochemical detection of l-ascorbic acid (AA). The dealloying process was used to create the main porous gold wire, and then electrochemical anodizing was adopted to construct the fine structure for nanoporous electrode. Furthermore, followed by chemical reduction with the enediol group in AA, the surface of S/NP-Au wire changed from a laminated to a scattered structure, and the preferred Au (2 0 0) high-index plane was investigated. As a result of synergistic electrocatalytic activity of Au wire skeleton towards AA, amperometric AA electrochemical sensors based on the S/NP-Au wire electrodes exhibit linear detection ranges with ultrahigh sensitivities at a low potential of 0.20 V (vs Ag. AgCl). The detection range of 0.3 μM–923.3 μM with a short response time of less than 1 s gives rise to ultralow detection limit of 26.3 nM (S/N = 3). The excellent characteristics of this sensor demonstrates it is a useful tool for accurate determination of AA in commercially available beverages such as water-soluble beverages with recoveries of 97.35 % to 110.7 %. The S/NP-Au electrode is a promising material for non-enzymatic AA detection.