A method for producing a radiofluorinated compound which has an aromatic or heteroaromatic ring which carries [ 18 F] fluorine as a first substituent, a bonding unit which can bind to a peptide, as well as a spacer group which connects the aromatic or heteroaromatic ring to the bonding unit, wherein the aromatic or heteroaromatic ring carries [ 18 F] fluorine as the first substituent, wherein the bonding unit carries at least one second substituent selected from the group consisting of -OH, -CONH, and -COOH, wherein the bonding unit is connected to the spacer group via a bond A 1 and the spacer group is connected to the aromatic or heteroaromatic ring via a bond A 2 and wherein the method comprises the steps of: (a) providing a precursor which has the aromatic or heteroaromatic ring which carries a substituent Y, the bonding unit which can bind to the peptide and which carries at least one second substituent selected from the group consisting of -OH, -CONH, and -COOH, as well as the spacer group, wherein the aromatic or heteroaromatic ring, which carries a substituent Y, is of general formula VId wherein - X each is C-R 8 or N, with the provision that at most two of the moieties X are N and the remaining of the moieties X are C-R 8 and R 8 each independently is the bond A 2 to the spacer, hydrogen, or unsubstituted or substituted C 1 -C 6 alkyl, with the provision that exactly one residue R 8 is a bond A 2 to the spacer group and the remaining ones of R 8 are the same or different from each other and each represent hydrogen or unsubstituted or substituted C 1 -C 6 alkyl; and - the substituent Y is selected from the group consisting of -N+(R 1 R 2 R 3), -NO 2, -Cl, -Br, -F, or -I, and R 1, R 2 and R 3 are the same or different from each other and each are unsubstituted or substituted C 1 -C 6 alkyl, wherein the precursor only differs from der radiofluorinated compound in that the substituent Y is replaced by [ 18 F] fluorine; and (b) reacting the precursor with a [ 18 F] fluoride anion in the presence of an activation salt to the radiofluorinated compound in a one-stage synthesis, wherein the substituent Y is replaced by [ 18 F] fluoride and wherein the activation salt has a cation of general formula N + (R 4 R 5 R 6 R 7), wherein R 4, R 5, R 6, and R 7 are the same or different from each other and each are unsubstituted or substituted C 1 -C 6 alkyl. (a) providing a precursor which has the aromatic or heteroaromatic ring which carries a substituent Y, the bonding unit which can bind to the peptide and which carries at least one second substituent selected from the group consisting of -OH, -CONH, and -COOH, as well as the spacer group, wherein the aromatic or heteroaromatic ring, which carries a substituent Y, is of general formula VId wherein - X each is C-R 8 or N, with the provision that at most two of the moieties X are N and the remaining of the moieties X are C-R 8 and R 8 each independently is the bond A 2 to the spacer, hydrogen, or unsubstituted or substituted C 1 -C 6 alkyl, with the provision that exactly one residue R 8 is a bond A 2 to the spacer group and the remaining ones of R 8 are the same or different from each other and each represent hydrogen or unsubstituted or substituted C 1 -C 6 alkyl; and - the substituent Y is selected from the group consisting of -N+(R 1 R 2 R 3), -NO 2, -Cl, -Br, -F, or -I, and R 1, R 2 and R 3 are the same or different from each other and each are unsubstituted or substituted C 1 -C 6 alkyl, wherein the precursor only differs from der radiofluorinated compound in that the substituent Y is replaced by [ 18 F] fluorine; and - X each is C-R 8 or N, with the provision that at most two of the moieties X are N and the remaining of the moieties X are C-R 8 and R 8 each independently is the bond A 2 to the spacer, hydrogen, or unsubstituted or substituted C 1 -C 6 alkyl, with the provision that exactly one residue R 8 is a bond A 2 to the spacer group and the remaining ones of R 8 are the same or different from each other and each represent hydrogen or unsubstituted or substituted C 1 -C 6 alkyl; and - the substituent Y is selected from the group consisting of -N+(R 1 R 2 R 3), -NO 2, -Cl, -Br, -F, or -I, and R 1, R 2 and R 3 are the same or different from each other and each are unsubstituted or substituted C 1 -C 6 alkyl, (b) reacting the precursor with a [ 18 F] fluoride anion in the presence of an activation salt to the radiofluorinated compound in a one-stage synthesis, wherein the substituent Y is replaced by [ 18 F] fluoride and wherein the activation salt has a cation of general formula N + (R 4 R 5 R 6 R 7), wherein R 4, R 5, R 6, and R 7 are the same or different from each other and each are unsubstituted or substituted C 1 -C 6 alkyl.