determination of copper ion by square wave anodic stripping voltammetry at antimony trioxide-modified carbon nanotube paste electrode

In this work, an antimony trioxide-modified multi-walled carbon nanotube paste electrode (sb2o3/cntpe) was employed for determination of cu2+ ions by using square wave anodic stripping voltammetry (swasv) in the presence of 8-hydroxy-7-iodo-5-quinoline sulfonic acid (hiqsa) as a chelating agent. the field emission scanning electron microscopy (fe-sem), energy-dispersive spectroscopy (eds) and electrochemical impedance spectroscopy (eis) methods were applied to estimate the morphology and properties of the modified electrode. measurements related to swasv were taken in 0.6 m hcl at −1.0 v versus ag|agcl|kcl (3 m) for 90 s (deposition step). after equilibrium time of 15 s, an asv appeared at 0.0 v versus ag|agcl|kcl (3 m) (stripping step). the sensor depicted a fairly linear response for cu2+ in the concentration range of 2–100 ppb with appropriate detection limit about 0.39 ppb and limit of quantification about 1.3 ppb. the stability of the modified electrode during 7 weeks and its behavior in the presence of some metal ions was evaluated. the practical applicability of the sb2o3/cntpe was established on the voltammetric determination of cu2+ in tap water as a sample.