Zinc layered hydroxide-2(3-chlorophenoxy)propionate modified multi-walled carbon nanotubes paste electrode for the determination of nano-molar levels copper(II)

A multi-walled carbon nanotube (MWCNT) paste electrode modified with zinc layered hydroxide-2(3-chlorophenoxy)propionate (ZLH-CPPA) was evaluated for the voltammetric determination of Cu(II). The optimum conditions were obtained at 2.5% (w/w) ZLH-CPPA: MWCNT, 4 × 10−3 M CH3COONa, pH 2.5 (with addition of CH3COOH) and scan rate 500 mV s−1. The cyclic voltammetric response was linear in the concentration range of 1.0 × 10−9–1.0 × 10−6 M Cu(II) and 1.0 × 10−5–1.0 × 10−3 M Cu(II) with a limit of detection 1.0 × 10−10 M Cu(II). Most metal ions present in excess of 25 times the concentration of Cu(II) did not interfere except from Fe(II), Ba(II), Pb(II) and Ca(II). The developed modified electrode showed high sensitivity, selectivity, and was applied for determination of copper in corn flakes and milk powders.