engleski

Chemical characterization of sea-surface microlayer by using electrochemical methods

As an area of exchange of matter and energy, the sea surface microlayer is an important boundary, that either affects or is affected by global change. The sea-surface microlayer is generally enriched in organic substances, particularly those which are surface active, metal ions, bacteria and other microorganisms, relative to subsurface ater. Electrochemical methods are very suitable for the study of surface-active organic matter. These ethods take advantage of the fact that adsorption of surface-active molecules on a mercury electrode cause measurable changes in the electrode double layer capacity or capacity current. Surface active substances (SAS) in seawater samples are determined by phase sensitive alternating current (a.c.) voltammetry using two approaches: (1) out-of-phase measurements based on the decrease in capacitive current in the presence of adsorbed SAS at - 0.6 V, and (2) in-phase measurements using oxido-reduction processes of o-nitrophenol as an electrochemical probe. Here we briefly present electrochemical results for three pairs of microlayer (ML) and underlying water (ULW) samples. Results are compared to the dissolved organic carbon (DOC) and total lipids concentrations.

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