▎ 摘　　要

In this work, oxidized graphene nanoribbons (GNRox) and reduced graphene nanoribbons (GNRred) were explored for the construction of disposable electrochemical sensors on screen-printed platforms for the sensing of ascorbic acid (AA), levodopa (LD) and uric acid (UA). GNRred demonstrated improved electroanalytical performance in comparison not only with the carbon screen printed electrodes (CSPEs), but also with other related carbon nanomaterials such as multiwalled carbon nanotubes (MWCNTs) and GNRox. MWCNTs served as the carbon source for GNRox which was further reduced to form GNRred. The excellent electrocatalysis exhibited by this carbon nanomaterial toward AA, LD and UA allowed a fast (100 s), selective (at +0.08, +0.27 and +0.39 V, respectively), and accurate determination (with recoveries between 97 to 101%) of these analytes in urine samples. Excellent intra-electrode repeatability (RSD <5%, n = 10), inter-electrode reproducibility (RSD <13%, n = 5 electrodes) and stability of the sensor (the electrode maintained 93 +/- 3% of its signal after 15 days) were also demonstrated, becoming this electrochemical sensor a valuable tool for clinical routine uric acid assessment. Tailored graphene nanoribbons on screen-printed platforms become a new generation of disposable graphene-based electrochemical sensors for POC testing applications. (C) 2014 Elsevier Ltd. All rights reserved.