Noncovalent nanohybrid of cobalt tetraphenylporphyrin with graphene for simultaneous detection of ascorbic acid, dopamine, and uric acid

A noncovalent nanohybrid of cobalt tetraphenylporphyrin (CoTPP) with chemically reduced graphene oxide (CRGO) was prepared through pi-pi stacking interaction between CRGO and CoTPP. The hybrid (CoTPP-CRGO) was characterized by UV-vis spectroscopy, Raman spectroscopy, and atomic force microscopy. The electrochemical behaviors of ascorbic acid (AA), dopamine (DA), and uric acid (UA) at CoTPP-CRGO modified glass carbon electrode (CoTPP-CRGO/GCE) were studied by cyclic voltammetry (CV). Three well-resolved oxidation peaks were obtained. The peak potential separations were 225 and 140 mV for AA and DA, DA and UA respectively. Owing to the synergistic effect of CoTPP and CRGO, CoTPP-CRGO showed faster electron transfer and stronger electrocatalysis than CoTPP, CRGO or their mixture. The proposed modified electrode exhibited linear responses to AA, DA and UA in the ranges of 5.0-200.0 mu M, 0.1-12.0 mu M, 0.5-40 mu M, respectively. The detection limits were 1.2, 0.03, and 0.15 mu M, respectively. It was also applied to detect real samples with a satisfactory result. (C) 2013 Elsevier Ltd. All rights reserved.