Anodic stripping voltammetric analysis of different species of copper in seawater using an electrochemical sensor

The behavior, effects, and toxicity of an element often depend largely on its speciation. In this study, the speciation of copper (Cu) in seawater was investigated via the fixed-point determination of electroactive Cu, acid-dissolved Cu, inert Cu, and total dissolved Cu using a voltammetric method with an electrochemical sensor. This method was found to be simple and effective for speciation analysis as no complicated pretreatment or separation steps were required, permitting its use for the direct determination of Cu speciation in real water samples with confirmed accuracy. Moreover, following simple electrolytic cleaning, the sensor exhibited good measurement stability and reproducibility when it was reused. Fixed-point determinations of electroactive Cu, acid-dissolved Cu, inert Cu, and total dissolved Cu in local seawater were carried out for 15 days. The total dissolved Cu concentration ranged from 45.03 to 122.85 nM, and its average concentration was 66.05 nM. The speciation of Cu was influenced by external environmental changes to some extent but was observed to remain relatively constant. The correlations between the concentrations of different Cu species and environmental parameters are discussed here in detail.