Determination of Trace Amounts of Copper(I) with a Chemically Modified Carbon Paste Electrode

Abstract

In this paper, a new sensitive and selective differential pulse voltammetric method for the preconcentration and determination of copper(I) in an aqueous medium is proposed. A carbon paste electrode modified with Nafion and 2, 2′- biquinoline is used for the accumulation of copper(I) from a dilute solution, followed by voltammetric quantification of the accumulated analyte. The electrochemical behavior of the accumulated analyte is characterized by cyclic voltammetry and differential pulse voltammetry. The surface of the modified electrode is renewed by holding the electrode at a positive potential (0.8V (vs. SCE)) for a certain period of time. The factors, which influence the accumulation and electrochemical response, have been investigated. A detection limit of 1nM was obtained following 2min of accumulation time. For 10 accumulation/determination/renewal cycles with 50nM Cu(I), the response could be reproduced with a 4.4% relative standard deviation. Satisfactory results were obtained for the determination of copper in a variety of biological samples.