Ion Selective Electrode Mediated by Transfer Layer of Graphene Oxide for Detection of Ca2+ with Highly Sensitivity and Selectivity

A Ca2+ selective microelectrode was proposed through electrodepositing graphene oxide (GO) on carbon fiber as an efficient ion-electron transfer layer. The gold leaves were further synthesized at GO surface to increase the specific surface area, and provide a substrate for assembly of the specific ligands for Ca2+. GO with negatively charges greatly facilitated the electron transfer process from the recognition center to electrode surface, resulting in the apparently enhanced sensitivity towards Ca2+. Moreover, the developed ion-selective microelectrode exhibited good selectivity to Ca2+, and a good linear range from 10 μM to 10 mM with a detection limit of 5.91 ± 0.46 μM.