N-Doped Graphene-Supported Gold Nanorods for Electrochemical Sensing of Ascorbic Acid with Superior Sensitivity

Gold nanorod (AuNR)-decorated N-doped graphene (NG) was designed for the electrocatalytic detection of ascorbic acid (AA). The synergistic effect of NG with higher surface area, large number of binding sites for AuNRs, good conductivity and electrocatalytic activity, and AuNRs with higher surface area, faster electron-transfer ability, and special electrocatalytic performance achieves superior sensitivity for monitoring of AA. All kinds of spectral and morphological test methods were applied to characterize the prepared NG and AuNRs. Under the optimized pH, two wide linear relationships between the peak current and the AA concentration by differential pulse voltammetry (DPV) within the ranges of 5 × 10 –9 M to 1 × 10 –6 M, and 1 × 10 –6 M to 8 × 10 –3 M were observed, with a detection limit as low as 2.6 nM. In addition, high reproducibility, stability, and great potential in the quantification of AA in diluted real human serum were also achieved by the combined electrochemical sensor. All the results indicate that the AuNR/NG sensing interface can be used as a promising material in the field of electrochemical sensors. Graphical Abstract