Disposable graphene sensor with an internal reference electrode for stripping analysis of heavy metals

In this study, a low-cost disposable graphene sensor was fabricated for detecting heavy metals such as Cd2+, Pb2+ and Cu2+ by the anodic stripping voltammetry method (ASV). Vacuum compacted graphene films were used as the three electrodes, and they showed excellent conductivity and low noise signals. A big advantage was the simple fabrication process of graphene films without any binder. Furthermore, a ferrocene-based internal reference was introduced in the working electrode. The analytes were recognized by the relative distances of the stripping potential peaks between the working electrode and internal reference electrode. Finally, the all-graphene-based sensor was successfully built for the electrochemical analysis and then applied for determination of heavy metals in real river-water samples.