▎ 摘　　要

An electrochemical sensor based on the electrocatalytic activity of graphene (Gr) for sensitive detection of caffeine is presented. The electrochemical behaviors of caffeine on Nafion-Gr modified glassy carbon electrode (Nafion-Gr/GCE) were investigated by cyclic voltammetry and differential pulse voltammetry. The results showed that the Nafion-Gr/GCE exhibited excellent electrocatalytic activity to caffeine. Caffeine can be effectively accumulated at Nafion-Gr/GCE and produce a sensitive anodic peak. Such electrocatalytic behavior of Gr is attributed to its unique physical and chemical properties, e.g., subtle electronic characteristics and strong adsorptive capability. This electrochemical sensor shows an excellent performance for detecting caffeine with a detection limit of 1.2 x 10(-7) M (S/N = 3), a reproducibility of 5.2% relative standard deviation, and a satisfied recovery from 98.6% to 102.0%. The sensor shows great promise for simple and sensitive determination of caffeine. (C) 2011 Elsevier B.V. All rights reserved.