Development and characterization of a recycled plastic based ion-selective electrode (PB-ISE) using CNT ink as ion-to-electron transducer

Environment care is currently a crucial priority due to the increase in worldwide pollution. Nanotechnology and recycled material could be used as a platform to know more easily some analytical ion concentrations. In this investigation, a recycled plastic-based ion-selective electrode (PB-ISE) to use as a potentiometric sensor was built using a transductor material as carbon nanotubes ink (CNT-ink) and a metalized polyester sheet (MPS) from packing residues. To make the electrode, CNT-ink is applied and spread onto the MPS surface adding cycles of 1 ml at 100°C until a maximal reduction in the electrical resistance and a stable roughness were observed. Once the conductive plastic is ready, it's covered with adherable plastic masks on both sides of MPS to protect it from liquids. The final step is the addition of the ion-selective membrane (ISM) for potassium determination on a circular orifice, which is located on the front mask. The results obtained were compared with a classical solid-contact ion-selective electrode (SC-ISE). Some analytical parameters as sensitivity, linear ranges, and limits of detection of the recycled plastic electrode were comparable with those obtained for the SC-ISE. The best performance was reported for the PB-ISE that afforded a near-N ernstian response (52.08± 2.36 mV) with a linear range from 10^-4 to 10^-1M and a limit of detection of 0.0176 mM. The potentiometry technique presents advantages in comparison with other techniques as well as a reduction in the cost and instrumental equipment to measure a wide range of analytes. Also, the straightforward fabrication and robustness that embrace the ISE could create an advantage technique using residual material from food packaging.