Stripping voltammetry of cerium(III) with a chemically modified carbon paste electrode containing functionalized nanoporous silica gel

This research introduces the design of an adsorptive stripping voltammetric method for the cerium(III) determination at a carbon paste electrode, chemically modified with dipyridyl-functionalized nanoporous silica gel (DPNSG-CPE). The electroanalytical procedure comprised two steps: the Ce(III) chemical accumulation at - 200 mV followed by the electrochemical detection of the Ce(III)/dipyridyl complex, using anodic stripping voltammetry. The factors, influencing the adsorptive stripping performance, were optimized including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The resulting electrode demonstrated a linear response over a wide range of Ce(III) concentration (1.0 - 28 ng mL(-1)). The precision for seven determinations of 4 and 10 ng mL(-1) Ce(III) was 3.2% and 2.5% (relative standard deviation), respectively. The prepared electrode was used for the cerium determination in real samples and very good recovery results were obtained.