Imprinting of different types of graphene oxide with metal cations

It is known that graphene oxide (GO) particles bear negatively charged oxygen moieties which can interact with cations, what has been several times employed in fabrication of electrochemical sensors for metals. In this work, for the first time GO was treated with Cu2+, Cd2+ or Pb2+ cations in a way similar to the ion imprinting by simple incubation of the two components and the synthesized nanomaterials were then deposited on carbon electrode surface forming electrochemical sensors towards lead cations. It was found that simple filtration of GO is very efficient way for collection of GO particles that could be imprinted most efficiently in terms of high electrochemical response towards lead cations. Part of the success also lies in high redox potential of Cu2+ that turned to be the best choice for the GO imprinting. It was also proven that the electrodes modified with ion-imprinted GO could work as the sensors of Pb2+ in drop amount of solution as well as they provide stable response under flowthrough cell conditions suitable, for example, for online monitoring of water quality.