Response of the jalpaite membrane copper(II) ion-selective electrode in marine waters

Authors

  • Roland De Marco,

    Corresponding author
    1. School of Applied Chemistry, Curtin University of Technology, G.P.O. Box U 1987, Perth, Western Australia, 6001, Australia
    • School of Applied Chemistry, Curtin University of Technology, G.P.O. Box U 1987, Perth, Western Australia, 6001, Australia
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  • Denis J. Mackey,

    1. CSIRO Division of Oceanography, P.O. Box 1538, Hobart, Tasmania, 7001, Australia
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  • Alberto Zirino

    1. Code 361, RDT&E Division, Naval Command, Control and Ocean Surveillance Center, San Diego, California, 95152-5000, USA
    2. Instituto de Investigaciones Oceanologicas (U.A.B.C.), Ensenada, B.C., Mexico
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Abstract

The response of the Orion 94-29 CuII ion-selective electrode (ISE) [employing a jalpaite membrane] in seawater has been related to levels of free CuII yielding results for the Derwent River and San Diego Bay that are 2 to 3 orders of magnitude higher than those for the Pacific Ocean. Response data for the electrode in acidified seawater at pH 2 are internally consistent with total CuII levels determined using differential pulse anodic stripping voltammetry (DPASV) and graphite furnace atomic absorption spectrometry (GFAAS). It has been found that, even in acidified seawater, the organic ligands influence the response of the electrode, and this effect can be compensated successfully by either analyzing UV-photooxidized seawater and/or using a standard addition technique. The assigned ISE results for total CuII in acidified seawater fall within ± (0.1–0.5) pCu unit of values determined using GFAAS. Electrode drift in seawater can be minimized by using a polished electrode that has been conditioned in seawater for 24 h. The improved response rate of a conditioned ISE minimizes electrode soaking times and sample contamination through membrane corrosion.

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