Potentiometric Strip Cell Based on Carbon Nanotubes as Transducer Layer: Toward Low-Cost Decentralized Measurements

In this study, we developed a potentiometric planar strip cell based on single-walled carbon nanotubes that aims to exploit the attributes of solid-contact ion-selective electrodes for decentralized measurements. That is, the ion-selective and reference electrodes have been simultaneously miniaturized onto a plastic planar substrate by screen-printing and drop-casting techniques, obtaining disposable strip cells with satisfactory performance characteristics (i.e., the sensitivity is 57.4 +/- 1.3 mV/dec, the response time is <= 30 s within the linear range from log alpha(K+) = -5 to -2, and the limit of detection is -6.5), no need of maintenance during long dry storage, quick signal stabilization, and light insensitivity in short-term measurements. We also show how the new potentiometric strip cell makes it possible to perform decentralized and rapid determinations of ions in real samples, such as saliva or beverages.