The Complex Crystal of NaTCNQ-TCNQ Supported on Different Carbon Materials as Ion-to-Electron Transducer in All-Solid-State Sodium-Selective Electrode

This work demonstrates the application of conductive organic crystals (7,7,8,8-tetracyanoquinodimethane (TCNQ) and its sodium salt (NaTCNQ)) supported on carbon nanomaterials (CNMs) as solid contact layer in all-solid-state ion-selective electrodes (ASS-ISEs). As ion-to-electron transductor between the ionically conducting membrane and the electronically conducting glassy carbon new layers based on a high capacity of charge transfer and a redox TCNQ/TCNQ-reaction are proposed. Developed CNM-NaTCNQTCNQ-contacted sensors provided a near to Nernstian response to sodium and excellent electrical parameters. The highest electrode capacitance was 2.15 mF, as the potential drift (and electrodes resistance) are significantly reduced due to the presence in solid contact combination of materials having ionic or electron conductivity. Moreover, the introduction of NaTCNQ in sodium-selective electrodes improves their selectivity toward to interfering cations. Carbon nanomaterials type used in the interlayer affects, in the different way, the analytical and electrical parameters of proposed ASS-ISEs. The possibility of improving the electrodes sensitivity, linear range and detection limit, by changing the NaTCQ: TCNQ ratio, is also presented. (C) 2016 The Electrochemical Society.