Ascorbic acid (AA) is an important deoxidizer contained in food, drink and medicine. However, existing detection methods are time-consuming and complex to industrial production and quality testing. Here, we proposed a core–shell nanowires constructed electrochemical sensor to achieve the highly sensitive and selective recognition of AA with a long-term reusability. Cu nanowires with 30 nm diameter were served as both structure skeleton and reactant to induce in-situ growth of Cu-Fe Prussian blue layer with 10 nm thickness covering its surface to form a core–shell architecture. This nanocomposite couples advances of Cu and Prussian blue to possess both high electrocatalysis and conductivity. The as-prepared sensor shows an excellent sensitivity with an ultrawide linear range, together with the remarkable reusable ability during 30 days with 300 times of repetitive detection. Used for four kinds of juice and bear as real samples, this sensor can accurately reported AA concentration within 5 s.

抗坏血酸（AA）是食品、饮料和药品中含有的重要脱氧剂。然而，现有的检测方法对于工业生产和质量检测来说耗时且复杂。在这里，我们提出了一种核壳纳米线构造的电化学传感器，以实现对 AA 的高度敏感和选择性识别，并具有长期可重复使用性。直径为 30 nm 的 Cu 纳米线既用作结构骨架又用作反应物，以诱导 10 nm 厚度覆盖其表面的 Cu-Fe 普鲁士蓝层的原位生长以形成核 - 壳结构。这种纳米复合材料结合了铜和普鲁士蓝的进步，具有高电催化和导电性。所制备的传感器显示出优异的灵敏度和超宽的线性范围，30天重复检测300次，可重复使用能力强。用于四种果汁和熊作为真实样品，该传感器可在 5 秒内准确报告 AA 浓度。