A New Ion-Selective Electrode for Potentiometric Determination of Ce(III)

Abstract

A new membrane ion-selective electrode (ISE) for cerium(III) ions based on a new ligand N-[(Z)-2-chloro-2-(1-hydroxy-1,1,1-triphenyl phosphoranyl)-1-ethenyl]-4-ethyl-1-benzene sulfonamide, as ionophore was prepared. The electrode has a wide linear dynamic range (6.6 × 10⁻⁷ to 6.2 × 10⁻² M; n = 10; r = 0.9994), with a Nernstian slope of 19.5 ± 0.3 mV/decade and a low detection limit (2.3 × 10⁻⁷ M). It has a fast response time (<10 s) and good selectivity with respect to different metal ions and can be used for at least four months without any considerable change in potential response. The response of proposed sensor is independent of pH at range 4.5–8.5. This sensor was used as an indicator electrode in potentiometric titration of oxalate and fluoride ions with Ce³⁺ and also applied for determination of fluoride in pharmaceutical samples and measurement of cerium content in stainless steel samples.

Keywords:

• Cerium(III)
• Ion-selective electrode
• Potentiometric titration
• Fluoride
• Oxalate

Acknowledgment

We gratefully acknowledge the support of this work by Tarbiat Modarres University research council.