The present invention relates to a process of the invention for separating at least one first material from a mixture comprising this at least one first material and at least one second material, which comprises the steps: (A) Contacting of at least one magnetic particle and at least one bifunctional molecule or an adduct of the two with the mixture comprising the at least one first material and at least one second material so that an adduct is formed from the at least one magnetic particle, the bifunctional compound of the general formula (I) and the at least one first material, (B) suspension of the adduct obtained in step (A) in a suitable suspension medium, (C) separation of the adduct present in the suspension from step (B) from the suspension by application of a magnetic field, (D) if appropriate, dissociation of the adduct separated off in step (C) in order to obtain the at least one first material. a corresponding adduct and the use of such an adduct for the separation of mixtures of materials.