Abstract: A device for measuring of impurities in a liquid, especially water, consists of a mixing chamber 16 where the liquid is mixed with a carrier gas, wherein the impurities at least in part are transposed into the gaseous phase, a separation chamber 28 and a gas pick-up 34 for measuring the gas mixture generated during the mixing and composed of the carrier gas and the impurities, which were transposed into the gaseous phase, whereby an acquisition of all ever so slight impurity concentrations are possible with a comparatively simple construction.