Abstract: The invention concerns a process and a device for taking samples in particular from waste gases containing substances of moderate and low volatility in a gas or aerosol phase. To this end, a partial current is diverted and conducted into a separation area (10), where the substances to be tested from the partial current, either in dust-bonding form or in the condensate, undergo a separation process and are fixed. When applied to a specific sample for the analysis of organic substances of medium to low volatility, in particular polychlorinated dibenzo(p)dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), the separation process can be restricted according to the invention in such a way that the partial current, together with the gaseous and liquid water portion contained in it, undergoes a two-stage separation process, where it is drawn through an inert dust-filter region (11), and drawn through a region (12) filled with an adsorber such as a synthetic adsorbent resin with a multi-reticular structure.