Interactional fingerprints offer an accessible, rapid, means to characterise graphene oxide.

Graphene-based materials (GBMs), including graphene oxide and graphene, are atomically thin materials with great promise, but efforts to realise this promise have been hampered by inconsistent material supply and the lack of rapid, accessible, characterisation methods. Here we present a new approach, based on surface interaction with a series of probe molecules, to rapidly provide a qualitative characterisation of graphene oxide materials at low cost, using widely available instruments. We demonstrate that our method can make qualitative comparisons, allowing us to observe if batches of material differ. Furthermore, in some circumstances it can quantify systematic differences, such as surface modification. We propose this approach may prove a valuable quality control method for materials producers and users alike and, since many applications of graphene oxide ¬— and 2D materials in general — depend on surface interactions, and suggest this kind characterisation may be valuable beyond rapid QC, in GBMs and other materials.