Electrochemical determination of organic surface active substances in model and natural sea water with Au(111) monocrystal electrode

Krznarić, Damir; Goričnik, Tihana; Ćosović, Božena (2000) Electrochemical determination of organic surface active substances in model and natural sea water with Au(111) monocrystal electrode. Croatica Chemica Acta, 73 (1). pp. 247-261. ISSN 0011-1643

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Abstract

The applicability of Au(111) monocrystal electrode for the determination of the amount of surface active organic substances was investigated using cyclic voltammetry, CV, and phase selective alternating current voltammetry, PSACV. The behaviour of the electrode was tested in a simple sea water model solution (0.55 M NaCl or 0.55 M NaCl plus 9.6 x 10(-4) M KBr), as well as in natural sea water samples from the northern Adriatic. Surface active organic molecules used for model adsorption investigations were Triton X-100, T-X-100, and humic acid, HA. Their behaviour in NaCl medium is discussed and typical CV and PSACV curves are compared for Cl- and Br- media. The characteristic of Au(111) surface reconstruction to be lifted by the adsorption of anions such as Cl- or Br- was used for analytical purposes, since competition in adsorption between inorganic anions and organic molecules changes strongly the reconstruction behaviour of Au(111). Calibration curves for T-X-100 and HA in model sea water were constructed and were used for determination of the relative concentrations of surface active molecules in natural sea water samples. The PSACV method was chosen as more reproducible and practical since no deaeration of the solution was necessary.

Item Type:

Article

Uncontrolled Keywords:

surface active substances; electrochemical determination; sea water; gold(111) electrode; Triton X-100; humic acid; anodic-stripping voltammetry; single-crystal planes; elementary steps; gold surfaces; adsorption; copper; metals; reconstruction; seawater; behavior

Subjects:

NATURAL SCIENCES > Chemistry

Divisions:

Division for Marine and Enviromental Research

Projects: