Gold nanoparticles as analytical tools for the quantification of small quantities of triazine derivatives anchored on graphene in water dispersions

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. MALDI-TOF was used to confirm the results obtained with the colorimetric methodology. Elemental analysis results were employed as the standard measurements.