The integration of chemo/bio sensors in large wireless sensing networks (WSN) is currently limited,
largely due to the issues related with power consumption and data handling. Also, there are very few
low cost chemo/bio sensors that combine sensitive, low limit of detection capabilities with simple
experimental setup. However, with recent advances, ion-selective electrodes (ISEs) may become an
excellent candidate for deployment in WSNs.
In this paper, we describe a solid-contact electrode based on poly(3-octylthiophene) (POT) as an
internal contact. We report its characteristics and its application to the for measurement of Pb2+ in 16
soil samples, with a ultimate goal of producing a small, simple and sensitive sensor that can be
integrated into WSNs. The electrode had a detection in the soil digestion matrix (1×10-3 M HNO3) of
1×10-7 M (20 ppb). The electrodes results were compared with atomic absorbtion spectrometry (AAS)
as a common instrumental technique used in soil analysis. We also report on the performance of solid-contact
ISEs based on polypyrrole (PPy) and POT. A superior detection limit of POT- relative to PPy-based
ISEs was observed. Furthermore, a good correlation has been observed between POT-based ISEs
and AAS and between the two types of ISEs.