engleski

Electrochemical investigations of sea-surface microlayer samples

The electrochemical method, based on the measurement of adsorption effects at the mercury electrode is applied for the investigation of sea surface microlayers. The sea-surface microlayer has been defined as the top 1 to 1000m of the sea surface. It represents the interfacial region where many organic substances are highly enriched and where important bio-physico-chemical processes and exchange of gases are taking place. Sea-surface microlayers collected by special device can be studied either without pretreatment, or they can be previously extracted by organic solvent and then investigated as ex-situ reconstructed film. Such films are then transferred to the mercury electrode by vertical dipping of the electrode through the film. In this work we determined capacitance of the original samples and ex-situ reconstructed films by using phase sensitive alternating current voltammetry. Additional characterization of ex-situ reconstructed microlayers, as well as of the original samples have been done by using cadmium as an electrochemical probe. On the basis of capacitance measurements and determination of degree of inhibition, characterization of the investigated microlayer samples have been done. Organic substances with different hydrophobic properties and different functional groups were found in original sample and in ex-situ reconstructed films what resulted in different adsorption and inhibition behaviour. Optical visualization of the microlayers have been performed by using Brewster angle microscopy. This method provides information about the homogeneity of the film, existence and formation of domains and phase transitions. Comparison with electrochemical data will be done.

Sea-surface microlayer; electrochemical studies

nije evidentirano