Characterization of modified carbon paste electrode by using Salen Schiff base ligand immobilized on SiO2–Al2O3 as a highly sensitive sensor for anodic stripping voltammetric determination of copper(II)

The wish of this work is to develop a Schiff base ligand covalently linked onto the SiO2–Al2O3 mixed-oxide as a new modifier of carbon paste electrode for highly sensitive voltammetric determination of copper(II). It is also an easy and inexpensive way for determination of copper(II). For the preliminary screening purpose, the Schiff base ligand was prepared by modification of SiO2–Al2O3 mixed-oxide and characterized by TG, CHN elemental analysis and FT-IR spectroscopy. Linear response to copper(II) was found in the 3.4 × 10−10–3.3 × 10−7 mol L−1 (r2 = 0.9994) concentration range, with a detection limit estimated at 1.8 × 10−10 mol L−1 (3Sb/m). The multiple determinations (n = 3) of copper(II) in the concentration of 5.0 × 10−4, 1.8 × 10−5, 2.0 × 10−7 and 1.0 × 10−8 mol L−1, following a preconcentration detection–regeneration cycle, displayed a relative standard deviation of lower than 1.07%. The developed sensor could also be used to determine the copper(II) in tap water and real samples. The copper content of the samples were comparable with the results obtained through AAS method.