Sono-cathodic stripping voltammetry of lead at a polished boron-doped diamond electrode: Application to the determination of lead in river sediment

Ultrasonically-assisted cathodic stripping voltammetry at a boron-doped diamond electrode, has been developed for the detection of lead. At concentrations above 3 μM, linear sweep voltammetry was used to give the analytical signal from a cathodic strip of electrodeposited PbO₂; linearity was observed from 3-100 μM, with 3 μM being the lower detection limit. Square-wave voltammetry was then employed for the cathodic stripping step, to lower the detection limits of the technique while retaining linearity to the order of 10^-8M. The procedure involves ultrasonic electrode cleaning, cathodic preconditioning and sono-anodic deposition of PbO₂. This novel analytical tool is mercury-free, oxygen insensitive and highly specific towards lead, yet still offers scope for further elemental diversity, particularly for the detection of copper and iron. The square-wave sono-cathodic stripping voltammetry technique was combined with an ultrasonically assisted acid digestion protocol to successfully determine the lead content of a contaminated sample of river sediment, offering significant time saving over the currently used analytical procedure.