Graphene Oxide from Improved Hummers’ Method: Is This Material Suitable for Reproducible Electrochemical (Bio)Sensing?

Abstract

Graphene as a superior nanomaterial is currently omnipresent and electroanalytical applications are not an exception. In this contribution, its suitability for such applications was critically assessed. We synthesized graphene oxide (GO) in five separate but identical experiments using the improved Hummers’ method – well-known and extensively utilized procedure which is typically followed by various operations leading to reduced graphene oxide material. These five repeated trials were precisely controlled to keep the experimental conditions as identical as possible. The resulting five individual GO products were compared by means of elemental analysis, Raman spectroscopy, ICP-MS and AFM.The possible employment of such graphene products - electrochemically reduced GO - for electroanalytical purposes was also probed from the viewpoint of the reproducibility of modification of electrodes and the results seem disconcerting, indicating poor reproducibility. No similar study in reproducibility has been performed until now, since all previous reports always compared only different methods of preparation and only discrete experiments of preparation – repeatability has not been properly addressed.