Sampling and analysis of single cloud and fog drops

The dependence of the concentration of solutes on the size of cloud or fog drops is investigated by analysing single drops. A new sampling method based on electrostatic precipitation that can be used either for sampling single cloud or fog drops (as small as 2 pl) or for sampling cloud and fog water as bulk phase has been developed. The sampled drops are stored and handled under paraffin oil. Inorganic cations and anions are analysed using capillary electrophoresis (CE). Absolute limits of detection are 10-13–10-15 moles. First results concerning the dependence of the concentration of solutes on the drop size are shown. In all cases a decrease of concentration of solutes with increasing drop size is observed.