Stable Pb2+ ion-selective electrodes based on polyaniline-TiO2 solid contacts

A novel Pb 2+ ion selective electrode based on a polyaniline-doped titanium dioxide (PANI-TiO 2 ) solid contact, denoted herein as GC/PANI-TiO 2 /Pb 2+ -ISE, was successfully developed. The GC/PANI-TiO 2 /Pb 2+ -ISE exhibited a stable and rapid potential response to Pb 2+ ions, with a linear response over the concentration range 10 −3 -10 −9  M, a detection limit of ∼10 −9.1  M and a response time of only 10–15 s. The PANI-TiO 2 solid contact layer possessed a large specific capacitance , thereby effectively promoting ion-to-electron transduction and enhancing the output stability (potential drift, 122.6 μV/s). The developed electrode maintained excellent performance during continuous use, showing a linear response range of 10 −3 -10 −7  M with no obvious changes in the potential response time or response slope (29 ± 0.2 mV/decade) over six weeks. Results encourage the wider use of conducting polymer-semiconductor solid contacts in ion selective electrode development.