engleski

Electrochemical Study Of The Surfactant Activity In Natural Microlayers Of The Saline Rogoznica Lake(Middle Adriatic)

The sea surface microlayer (SSM) as a key interface for exchange of gases, material and energy between the ocean and the atmosphere, consists of a wide variety of organic surface active substances (SAS). Determination of SAS in SSM by using alternating current (ac)voltammetry is a simple, rapid and non-destructive method for physicochemical characterization of natural films. The main location of SSM sampling was eutrophicated Rogoznica Lake (Middle Adriatic). Natural microlayer was studied as an original sample and as ex-situ reconstructed films after previous extraction by different organic solvents. Ac. voltammetry (out-of-phase) was used for quantification of SAS in original SSM and underlying water samples. The seasonal variability of SAS concentrations of SSM was observed and could be related with the periods of more extensive phytoplankton activity in the Rogoznica Lake. The ex-situ films were studied using modified ac. voltammetry method, transferring organic extract of natural microlayers spread onto electrolyte from the air-water interface to the mercury surface by vertical dipping the electrode through the film. Additional characterization of the structure of marine films was carried out by ac. voltammetry (in-phase) using redox processes of cadmium as an indicator of the permeability of different films adsorbed at the mercury electrode. This electrochemical methodology enables a new approach to the physicochemical characterization of sea surface films.

sea surface microlayer; surface active substances; electrochemical methods; Rogoznica Lake.

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