Fig. 6: Real time and simultaneous measurements of ion concentrations in a multi-ion electrolytic solution.
From: Selective ion sensing with high resolution large area graphene field effect transistor arrays
a The change in current ΔIds = ΔIi versus time t for all seven ISFETs measured concurrently in a multi-ion electrolytic solution, spiked at different time intervals with salt mixtures as illustrated by the arrows. b, c The calculated concentrations ai of the cations and anions, respectively, from the measured currents as determined from the Nikolskii–Eisenman equations. d The accuracy of concentration estimation by the ISFET sensor array is analyzed by comparing the concentrations calculated from the ISFET array currents in the shaded time interval with the concentration determined from the volume and mass of the added salts.
