Voltammetric determination of Cu(II) in natural waters and human hair at a meso-2,3-dimercaptosuccinic acid self-assembled gold electrode

An electrochemical sensor for the detection of copper(II) ions is described using a meso-2,3-dimercaptosuccinic acid (DMSA) self-assembled gold electrode. First in ammonia buffer pH 8, copper(II) ions complex with self-assembled monolayer (SAM) via the free carboxyl groups on immobilized meso-2,3-dimercaptosuccinic acid (accumulation step). Then, the medium is exchanged to acetate buffer pH 4.6 and the complexed Cu(II) ions are reduced in negative potential of −0.3 V (reduction step). Following this, reduced coppers are oxidized and detected by differential pulse (DP) voltammetric scans from −0.3 to +0.7 V (stripping step). The effective parameters in sensor response were examined. The detection limit of copper(II) was 1.29 μg L⁻¹ and R.S.D. for 200 μg L⁻¹ was 1.06%. The calibration curve was linear for 3-225 μg L⁻¹ copper(II). The procedure was applied for determination of Cu(II) to natural waters and human hairs. The accuracy and precision of results were comparable to those obtained by flame atomic absorption spectroscopy (FAAS).