▎ 摘　　要

An ultra-sensitive sensor is described for the voltammetric determination of ascorbic acid (AA). A glassy carbon electrode (GCE) was modified with graphene oxide (GO), multi-walled carbon nanotubes (MWCNTs) and gold nanorods (AuNRs). GO was used to prevent the aggregation ofMWCNTs. The integration of positively charged AuNRs reduces the overpotential and increases the peak current of AA oxidation. Figures of merit of this sensor, typically operated at a low working potential of 0.036 V (vs. Ag/ AgCl), include a low detection limit (0.85 nM), high sensitivity (7.61 mu A center dot mu M-1 center dot cm-2) and two wide linear ranges (from 1 nM to 0.5 mu Mand from1 mu Mto 8 mM). The use ofGO simplifies the manufacture and results in a highly reproducible and stable sensor. It was applied to the quantification of AA in spiked serum.