DIFFERENTIAL-PULSE ANODIC-STRIPPING VOLTAMMETRIC DETERMINATION OF COPPER(II) WITH N-PHENYLCINNAMOHYDROXAMIC ACID MODIFIED CARBON-PASTE ELECTRODES

Copper(II) was selectively accumulated, at open circuit, on a carbon p aste electrode incorporating N-phenylcinnamohydroxamic acid. The ensui ng measurements were carried out by differential pulse anodic strippin g voltammetry. Factors affecting the accumulation, reduction, and stri pping steps were investigated and a procedure was developed. Two linea r ranges were obtained in the concentration ranges 1.00 x 10(-8) -1.00 x 10(-6) M Cu(II) with 3 min preconcentration time and 1 min reductio n time and 1.00 x 10(-9) -1.00 x 10(-8) M Cu(II) with 10 min preconcen tration time and 2 min reduction time. The detection limit was found t o be 5.00 x 10(-10) M with 10 min accumulation and 2 min reduction tim e. For six successive determinations of 1.00 x 10(-8) and 5.00 x 10(-7 ) M Cu(II), relative standard deviations of 9.4 and 8.7%, respectively , were obtained. The modified electrode preferentially accumulates cop per from the solution, while most of the metal ions do not interfere w ith the determination. The developed method was applied to copper dete rmination in potable water and in commercial lithium chloride. (C) 199 8 Elsevier Science B.V. All rights reserved.