A process for obtaining a sample from an atmosphere in a closed gastight vessel, which comprises:
- passing a sample through a venturi nozzle immediately upon entry of the sample into a sample-taking container in a vessel;
- mixing the sample in the venturi nozzle with a transport fluid serving as a washing liquid;
- and
- subsequently discharging gaseous constituents of the sample being soluble and/or condensable in the washing liquid together with the washing liquid from the sample-taking container and from the vessel by triggering by a pressure reduction.