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Conductive Metal–Organic Frameworks as Ion-to-Electron Transducers in Potentiometric Sensors

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journal contribution
posted on 24.05.2018, 13:04 by Lukasz Mendecki, Katherine A. Mirica
This paper describes an unexplored property of conductive metal–organic frameworks (MOFs) as ion-to-electron transducers in the context of potentiometric detection. Several conductive two-dimensional MOF analogues were drop-cast onto a glassy carbon electrode and then covered with an ion-selective membrane to form a potentiometric sensor. The resulting devices exhibited excellent sensing properties toward anions and cations, characterized by a near-Nernstian response and over 4 orders of magnitude linear range. Impedance and chronopotentiometric measurements revealed the presence of large bulk capacitance (204 ± 2 μF) and good potential stability (drift of 11.1 ± 0.5 μA/h). Potentiometric water test and contact angle measurements showed that this class of materials exhibited hydrophobicity and inhibited the formation of water layer at the electrode/membrane interface, resulting in a highly stable sensing response with a potential drift as low as 11.1 μA/h. The property of ion-to-electron transduction of conductive MOFs may form the basis for the development of this class of materials as promising components within ion-selective electrodes.

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