In-situ growth of Cu@CuFe Prussian blue based core-shell nanowires for non-enzymatic electrochemical determination of ascorbic acid with high sensitivity and reusability

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.