Voltammetric determination of silver with a new multi-walled carbon nanotube modified paste electrode

Abstract

This study introduces the sensitive determination of silver using modified carbon paste electrode based on multi-walled carbon nanotubes and a new synthesized chelating agent of N-(4-{4-[(anilinocarbothioyl)amino]benzyl}phenyl)-N-phenylthiourea. This electrochemical method is based on accumulation of silver ions at the surface of a new multi-walled carbon nanotube modified paste electrode. After preconcentration, the measurements were carried out in a closed circuit by electrolysis of the accumulated Ag(I) ions by voltammetric scanning from −0.2 to +0.2 V. Under the optimized conditions, a linear response range from 0.5 to 270 ng mL−1 was obtained. The detection limit and relative standard deviation for seven replicate measurements were 0.079 ng mL−1 and ±2.4%, respectively. The procedure was applied to determination of silver(I) in water, tea leaves and a certified reference material with satisfactory results.