engleski

Polarography of marine particles: A model study

A simple polarographic method for direct measurement of surface active constituents of seawater was used to investigate the effect of variable levels of dissolved surfactants on the detection of attachment signals of surface active particles at the artificial interface. Mixture of dextran solutions and dispersion of insoluble squalene droplets simulates electrochemical signals in natural samples and allows prediction of behavior of natural organic particles. For the same distribution of particles in the aqueous dispersion, attachment signals frequency decreases exponentially with increasing bulk concentration of dissolved molecules. Attachment rate of particles at the dropping mercury electrode (DME) depends on the extent of surface coverage with adsorbed molecules (q). At full coverage of the electrode the particle attachment signals cannot be detected. The actual distribution of surface active particles can be determinated by direct measurement of attachment signals when q<0.5, which is the case of majority of seawater samples. For qł0.5, dilution with organic free electrolyte and/or sampling within the initial part of the DME life-time should be used.

marine particles; surface-active particles; surfactants; polarography

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