Nanostructured multi-walled carbon nanotubes derivate based on carbon paste electrode for potentiometric detection of Ag+ ions

Abstract

A new hybrid material (B15C5-MWCNTs) has been used as a neutral carrier in a carbon paste electrode for the detection of silver. B15C5-MWCNTs were synthesized by grafting 4′-aminobenzo-15-crown-5 (B15C5) onto acid-functionalized multi-walled carbon nanotubes (MWCNT-COOH) through a short 2-carbon chain spacer. The silver carbon paste electrode can be prepared by simple mixing of B15C5-MWCNTs, graphite powder and paraffin oil. B15C5-MWCNTs were not only ion-to-electron transducers but also reactive materials. With 8.4 wt% B15C5-MWCNTs proportions, the electrodes exhibited a linear response ranging from 2.7 × 10⁻⁷ to 1.0 × 10⁻¹ M with a near Nernstian slope of 58.5 mV dec⁻¹. The proposed electrode displayed rapid response (∼15 s) and long-time stability. Moreover, the potentiometric responses could be carried out with a wide pH range of 3.0–9.0. Then, the response mechanism of the proposed electrode was investigated by using AC impedance. Finally, the developed electrode was successfully applied in the determination of silver ions in radiology films and chloride ions in water samples.