Novel sensor fabrication for the determination of nanomolar concentrations of Ce3+ in aqueous solutions

Abstract

A new Ce³⁺ carbon paste electrode based on a nanocomposite containing multi-walled carbon nanotubes (MWCNTs), nanosilica, room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate), and 4-(4-methylbenzylideneamino)-5-methyl-2H-1,2,4-triazole-3(4H)-thione (L) as an efficient ionophore was prepared. This sensor responds to cerium ions in a wide linear dynamic range of 2.5 × 10⁻⁸ to 1.0 × 10⁻¹ mol L⁻¹ with Nernstian slope of 19.32 ± 0.10 mV per decade. The detection limit of 7.0 × 10⁻⁹ mol L⁻¹ was obtained at pH range of 3.0 to 8.0. It has a fast response with response time of about 5 s, and can be used for at least 11 weeks without any considerable divergence in the potentials. The proposed sensor displays an excellent selectivity for Ce³⁺ ions with respect to a large number of alkali, alkaline earth, transition and heavy metal ions. This sensor was successfully applied in the determination of cerium ions in aqueous samples.