All-solid-state potassium-selective electrode using graphene as the solid contact

Fenghua Li, Junjin Ye, Min Zhou, Shiyu Gan, Qixian Zhang, Dongxue Han, Li Niu

Research output: Contribution to journalJournal articleResearchpeer-review


Graphene sheets are used for the first time to fabricate a new type of solid-contact ion-selective electrode (SC-ISE) as the intermediate layer between an ionophore-doped solvent polymeric membrane and a glassy carbon electrode. The new transducing layer was characterized by transmission electron microscopy, scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The performance of the new K+−selective electrodes was examined by a potentiometric water layer test, potentiometric measurements, and current reversal chronopotentiometry. The obtained potentiometric sensors were characterized with a calibration line of slope close to Nernstian (59.2 mV/decade) within the activity from 10−4.5 to 0.1 M. The high capacitance of the graphene solid contacts results in a signal that is stable over one week. The short response time is less than 10 s for activities higher than 10−5 M. The potential drift of the electrodes was calculated from the slope of the curves at longer times (ΔE/Δt = 1.2 × 10−5 V s−1 (I = 1 nA) and ΔE/Δt = 5.5 × 10−5 V s−1 (I = 5 nA)). All the results indicate that graphene is a promising material for use as a transducer layer for SC-ISEs.
Original languageEnglish
Issue number3
Pages (from-to)618-623
Publication statusPublished - 2012


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