Determination of traces of copper by anodic stripping voltammetry at a rotating carbon paste disk electrode modified with poly(1,8-diaminonaphtalene)

Abstract

In the present work, carbon paste electrodes ( CPE ) modified with conducting polymers 1,8-diaminonaphtalene ( DAN ) was developed for the voltammetric determination of Cu(II). The modified electrode exhibited a significantly increased sensitivity and selectivity for Cu 2+ compared with a bare carbon paste electrode. Copper(II) was preconcentrated at open circuit on the modified electrode. The measurements were carried out using a rotating disk electrode ( RDE ) as working electrode. The experimental parameters for the determination of Cu(II) were optimized. The Cu(II) ions were chemically deposited onto the surface of poly DAN-CPE in an acidic medium. Under the optimum conditions, a linear calibration graph was obtained in the concentration range of 0.1 to 250 ppb with a correlation coefficient of 0.9998. The relative standard deviation for 6 successive determinations was 4.7%. A study of interfering substances was also performed, and the method was applied to the direct determination of copper in real samples like tap water and orange juice samples.