Fig. 7: Measuring ion concentrations in an aquarium.
From: Selective ion sensing with high resolution large area graphene field effect transistor arrays
a An optical image of the ISFET array in an aquarium containing duckweed. b The measured ion concentrations in the aquarium over time. The concentrations were calculated from the measured currents using the series of Nikolskii–Eisenman equations. After the eighth day, salts were added to the aquarium as nutrients for the plants.
