engleski

Electroanalysis of organic particles in water systems

Organic matter in natural waters is a mixure of different compounds (from simple hydrocarbons to complex biogeopolymers) present as dissolved molecules, submicron particles and also micron particles (ł1mm) with concentration occasionally approaching 108/l in the euphotic and mixing layers (1). Their reactivity and importance for biogeochemical processes are still unknown. Chronoamperometry of dissolved oxygen on fast dropping mercury electrode (2) is used as a metod for direct characterization of organic particles in sodium chloride solution and seawater. Phytoplankton organism Dunaliella tertiolecta (8-10 mm) has been chosen as a model particle because it forms stable suspensions, has fluid cell wall, and similar to organic droplets (3,4), adhesion of cells to the electrode results in electrical attachment signals. Their duration is 0.06-0.2 s, and amplitudes 0.6-2.2 mA. From dependence of freqency of attachment signals on the cell density in suspension, we constructed calibration curves for measurement of concentration and size of organic particles in aquatic sample in the concentration range 105-108/l, and sizes ł1 mm.

organic particles; Dunaliella tertiolecta; chronoamperometry

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