Sensitive detection of ascorbic acid using screen-printed electrodes modified by electroactive melanin-like nanoparticles

In this work, we report on the design of an enzyme-less sensitive and selective electrochemical electrode for ascorbic acid (AA) detection using a modified screen-printed electrode of melanin-like nanoparticles (Mel-NPs). Cyclic voltammetry shows that the melanin-modified electrode exhibits high electrocatalytic activity for ascorbic acid. The melanin-like nanoparticles serve as a shuttle to transport electrons from ascorbic acid to the electrode surface. The modified electrode is endowed with a large dynamic window ranging from 5 to 500 ppb. The detection and quantification limits were estimated to be 0.07 and 0.23 ppb, respectively. The modified electrode was successfully used to determine AA in human blood serum, urine and saliva with satisfactory recovery levels.