Specifies a method of sampling by scrubbing at dry ice temperature (195 K). Permits the concentration of traces of all the less volatile polar compounds (water, alcohols, esters, acids, amines, etc.) in a small amount of liquid phase practically without any interference due to adsorption phenomena on the relatively small internal surfaces of the scrubbing absorber. This sampling technique permits the exact determination of all these polar compounds at contents greater than 0.01 mg/m^3, at normal temperature and pressure. Is also applicable to the determination of hydrocarbons with a higher boiling point (for example traces of oil in ethylene).