Dopamine is a neurotransmitter in the central nervous system. (7

8-

3

H) dopamine is an important tracer for the study of physiological functions and metabolic processes. It was prepared by catalytic reduction of 3-hydroxy-4-methoxy-8-nitro-styrene with tritium gas. At the end of reaction

hydrobromic acid was added and heated to remove the methoxyl group. The crude product was purified by paper chromatography. The purity of (7

8-

3

H) dopamine was identified by IR

UV

PC and

3

H-NMR spectra. The radiochemical purity was over 95

%

and the specific activity was 1.26×10

12

Bq/mmol(34Ci/mmol). The distribution of labelled tritium in molecule was shown as follows: 55.4% at position 7 and 44.6% at position 8.