Applicability of chemically modified electrodes for determination of copper species in natural waters

A procedure based on the stripping voltammetric determination of labile copper after its chemical accumulation on a graphite electrode modified with a complexation agent and a Nafion film is described. The method is sufficiently sensitive for the copper determination in the nM to μM range with a relative standard deviation of a 1 to 6%. The detection window of the proposed technique is similar to that of conventional differential pulse polarography. Results for the copper speciation and the copper complexation capacity in model samples and in river waters are presented. A mathematical description of competitive complexation equilibria is discussed.