The preparation and characterization of tritiated neurochemicals

As an element and constituent of exceedingly useful compounds, tritium has been extensively reviewed. It possesses some unique advantages as a radiolabel for neurochemicals or ligands. The high specific activity, relatively long half life and size similarity of tritium to hydrogen well recommend its use in autoradiography, receptor binding assay and metabolic studies. Depending for the most part upon commercial sources for such tritiated neurochemicals, investigators are largely unaware of the issues that attend their preparation, purification and storage. Thus, the purpose of this chapter will be to provide such a perspective. The author has chosen to divide the discussion into first the synthetic methods of preparation, purification and storage of tritiated ligands, and then the determination of their identity, purity, specific activity and position of radiolabeling. This discussion sequence closely parallels the actual order of events for preparing and characterizing a tritiated ligand. A discussion concerning the issue of chirality concludes the chapter. Several excellent reviews about 3H NMR have recently appeared. In this paper, the exploitation of 3H NMR as an analytical and problem solving tool has not been reviewed separately, but it has been integrated into the entire discussion wherever its impact was felt