engleski

Electrochemical impedance spectroscopy: application for sea surface microlayer characterization

Electrochemical methods have proven to be an efficient tool for physicochemical characterization of natural films and their application is of great interest to sea microlayer studies. Electrochemical impedance spectroscopy was applied as a highly sensitive method to understand better the behaviour of natural lipid layers on mercury electrodes. In order to investigate the physicochemical characteristics of natural films experimental procedures were used to obtain impedance data as a function of frequency and potential. The experiments were performed using: (1) a dynamic regime in which either the potential or the frequency were varied in small increments on the same adsorbed layer and (2) a dynamic regime on the same adsorbed layer but including a pre-treatment before every potential or frequency increment in order to restore the state of the film prior to application of the perturbation. The results for ex-situ reconstructed monolayers were compared with those of dioleyl lecithin (DOPC) which when adsorbed on the electrode represent a defect free monolayer. Results for reconstructed microlayers and their mixtures with DOPC enable a new approach to the physicochemical characterization of sea surface films. Applied electrochemical techniques have been designed and used for studies of lipid monolayers and has not yet been used for the characterization of natural aquatic films.

sea surface microlayers; impedance spectroscopy

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