Synergistic effect of a cobalt fluoroporphyrin and graphene oxide on the simultaneous voltammetric determination of catechol and hydroquinone.

Abstract

Graphene oxide (GO) was modified with the cobalt(II) and zinc(II) complexes (CoTFPP and ZnTFPP) of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin in order to improve the electrocatalytic activity of GO towards catechol (CC) and hydroquinone (HQ). It is found that the CoTFPP-modified GO on a glassy carbon electrode (GCE) displays the highest electrocatalytic activity. The response to CC (at0.14V vs. SCE) is linear in the 1-220μM concentration range. The response to HQ (at 0.04V vs. SCE) extends from 1μM to 200μM. The sensitivity and detection limits are 10.40μA∙μM-1∙cm-2 and 0.17μM for CC, and 8.40μA∙μM-1∙cm-2 and 0.21μM for HQ. Experimental results indicate that the Co(II) and Zn(II) ions in the porphyrins positively affect the electron transfer rate in the hybrid materials. The GCE modified with CoTFPP/GO was successfully applied to the simultaneous determination of CC and HQ in spiked samples of tap and lake water. Graphical abstract Schematic presentation of a voltammetric method for simultaneous determination of catechol (CC) and hydroquinone (HQ). It is based onthe use of a cobalt (II) fluoroporphyrin (CoTFPP) functionalized graphene oxide (GO) hybrid.