Functionalized graphene as an aqueous phase chemiresistor sensing material

Here we report on the successful detection of benzene, toluene, ethylbenzene, xylenes and cyclohexane dissolved in water at low ppm concentration levels using functionalized graphene in a microelectrode chemiresistor platform. The use of microelectrodes results in a small double layer capacitance that effectively impedes charge transfer through the solution and allows the resistance of the graphene film to be measured preferentially. Comparing the relative chemiresistor response between cyclohexane (a non-aromatic molecule) and aromatic compounds (e.g. toluene), we have deduced that the response mechanism is most likely due to film swelling and not doping through the direct interaction of the molecule with the graphene basal plane.