Abstract: A water sampling device for field use operates in cleaning and sampling modes and includes a distributor valve that provides selective connection of a sample pump to a plurality of collection units so that a plurality of samples can be taken. The collection units are composed of a filter for removing particulate matter, a liquid-solid extraction cartridge, and a storage bottle. Water samples are automatically collected from a river or other water source, and then pumped immediately through the liquid-solid extraction cartridge which extracts and retains the contaminants from the water. Once the contaminants have been extracted into the cartridge, the sample is chemically stable and resistant to degradation, thereby eliminating the need for much of the special handling of samples that was previously required with field units.