Lead (II) carbon paste electrode based on derivatized multi-walled carbon nanotubes: Application to lead content determination in environmental samples

For the first time a novel derivatized multi-walled carbon nanotubes-based Pb2+ carbon paste electrode is reported. The electrode with optimum composition, exhibits an excellent Nernstian response to Pb2+ ion ranging from 5.9 × 10−10 to 1.0 × 10−2 M with a detection limit of 3.2 × 10−10 M and a slope of 29.5 ± 0.3 mV dec−1 over a wide pH range (2.5–6.5) with a fast response time (25 s) at 25 °C. Moreover, it also shows a high selectivity and a long life time (more than 3 months). Importantly, the response mechanism of the proposed electrode was investigated using AC impedance technique. Finally, the electrode was successfully applied for the determination of Pb2+ ion concentration in environmental samples, e.g. soils, waste waters, lead accumulator waste and black tea, and for potentiometric titration of sulfate anion.