A method for the determination of concentrations with a separation of not microbial cells, as well as an apparatus for this purpose and reagent.

摘要

A method for substantially selectively removing adenosine triphosphate (ATP) from somatic cells in a sample containing somatic cells and bacteria comprising treating the sample with water to rupture the membranes of the somatic cells, and substantially removing or inactivating the ATP released. The treatment with water is preferably carried out in a water layer above the surface of a substrate material, in particular a filter material such as a membrane filter. Also a method for determining the number of bacteria on the surface of a substrate, said method comprising a) forming a closed chamber having an inner wall which is partly defined by the bacteria-bearing surface of the substrate; b) contacting the bacteria-bearing surface with an aqueous extraction medium capable of perforating the cell walls of the bacteria and extracting substantially all of the ATP present in the bacteria; c) transferring the extraction medium to a separate measuring chamber; d) adding luciferine and luciferase to the extraction medium so as to subject the ATP in the extraction medium to a luciferine/luciferase reaction; and e) determining the amount of ATP by measuring in the measuring chamber the light emitted as a result of the reaction and expressing the amount of ATP as the number of bacteria present on the substrate. m