Comparison of backing materials of screen printed electrochemical sensors for direct determination of the sub-nanomolar concentration of lead in seawater.

An anodic stripping voltammetric method is reported in this study for the determination of sub-nanomolar Pb concentration using disposable sensors, each consisting of three (counter, working and reference) screen-printed electrodes. Sensor performance was optimized for the determination of Pb through several surface modifications, by using single-walled carbon nanotubes, electro-reduced graphene oxide and gold nanoparticles. A scanning electron microscopy study of the deposition of electrogenerated gold nanoparticles of various sizes on the working electrode surface showed that spherical nanoparticles of around 100 nm provided the best results. The modification of working electrodes with graphene and gold nanoparticles permitted the determination of Pb2+ in seawater (Detection Limit: 3.21·10-10 M) without modifying the pH of the sample. The electrode systems were printed on both rigid and textile backing materials, to observe the influence of those materials on the final performance of the sensor.