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Anal. Chem. 2008, 80, 1316-1322

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Ion-selective electrodes using carbon nanotubes as ion-to-electron transducers
Crespo, GA; Macho, S; Rius, FX
Anal. Chem. 2008, 80, 1316-1322

This study developed a new type of all-solid-state ion-selective electrode based on a transducing layer of a network of single-walled carbon nanotubes.

The extraordinary capacity of carbon nanotubes to promote electron transfer between heterogeneous phases made the presence of electroactive polymers or any other ion-to-electron-transfer promoter unnecessary. The new transducer layer was characterized by environmental scanning electron microscopy and electrochemical impedance spectroscopy. The stability of the electrical potential of the new solid-contact electrode was examined by performing current-reversal chronopotentiometry, and the influence of the interfacial water film was assessed by the potentiometric water layer test. The performance of the new electrode was evaluated by determining K+ with an ion-selective membrane that contained the well-known valinomycin ion carrier. The new electrode had a Nernstian slope (58.4 mV/decade), dynamic ranges of four logarithmic units, and selectivities and limits of detection comparable to other solid-contact electrodes. The short response time (less than 10 s for activities higher than 10-5.5 M) and the stability of the signal over several days makes these new electrodes very promising candidates for attaining true miniaturization.
 

 Chemometrics, Qualimetrics and Nanosensors Group
Chemometrics, Qualimetrics
and Nanosensor Group

 Universitat Rovira i Virgili
Universitat Rovira i Virgili

NT Sensors
NT Sensors