[en] The requirement of selective radiopharmaceuticals for PET-diagnostics necessitates the development of new labelling methods taking into account the substantial and structural diversity of the compounds to be labelled. Therefore different concepts for ¹⁷F-fluorination of peptides, which are increasingly important as pharmaceuticals, via proline moieties were explored and evaluated in this work. The direct nucleophilic kryptate based ¹⁸F-fluorination of the model peptide Z-Pro-Leu-Gly-4-(4R)-(TsO)Pro-OMe showed, that the peptide is not stable under the basic labelling conditions, and as a result the ¹⁸F-fluorination is not possible. Perfluorbutane-1-sulfonyl[¹⁸F]fluoride is a possible reagent for ¹⁸F-fluorination of sensitive hydroxy groups containing biomolecules due to the mild reaction conditions at which aliphatic alcohols are fluorinated by this reagent. (orig.)