engleski

All-Solid-State Flexible Ammonium-Selective Electrode Based on Inkjet Printed Graphene Solid Contact

Continuous chemical monitoring presents an imperative for environmental and healthcarerelated analysis, often inaccessible to classical analytical techniques, such as HPLC and UV/Vis spectroscopy. Within the scope of this work, miniaturized planar electrochemical sensor platforms set up in an all- solid-state manner have been developed by inkjet printing. We developed, characterized and optimized the printing process of a planar all-solid-state ammonium ion-selective electrode (NH4-ASS-ISE) (Figure 1). Silver connection pads were made by inkjet printing commercial Ag-ink on flexible polymeric substrates. For the solid contacts, we have previously formulated an inkjet printable water-ethanol-ethylene glycol graphene suspension.1 The number of graphene overprints and the volume of the drop-cast ammoniumselective membrane were optimized with the aid of electrochemical impedance analysis, cyclic voltammetry and potentiometry. NH4- ASS-ISE prepared by 50 graphene ink overprints and dropcast with 120 μL of the ammonium-selective membrane demonstrated the best properties, in terms of sensitivity (64.3 mV/dec in the linear range from 10–4 M to 10–1 M NH4Cl), potential stability, reproducibility of measurements (n = 3), reversibility, and linearity (R2 = 0.9980).

graphene ; all-solid-state ion-selective electrodes ; inkjet printing ; potentiometric sensors

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