▎ 摘　　要

The development of new methodologies for the preparation of aqueous graphene dispersions is contributing to fostering their biological applications. However, there is still a need for analytical methods to fully characterise the different graphene materials and to identify the presence of other components in the medium in order to establish structure-behaviour correlations. We report here a fast, simple and sensitive method to detect ppm levels of melamine anchored on graphene in aqueous graphene dispersions. Gold nanoparticles can be directly cross-linked with melamine and the resulting aggregation produces a change in colour that can be readily detected in the presence of graphene. Visible changes can be observed with the naked eye and determined by UV-Vis spectroscopy. MALDITOF was used to confirm the results obtained with the colorimetric methodology. Elemental analysis results were employed as the standard measurements.