Removal of borate from tritiated gangliosides via the mannitoborate complex.

Purified gangliosides were radiolabeled by exposure to sodium boro [3H]hydride in the presence of palladium on barium sulfate. After centrifugation to remove the catalyst, borate was complexed with mannitol and the resulting mannitoborate complex and salts were removed by reversed phase chromatography. The labeled gangliosides were repurified by ion exchange and silica gel chromatographies. Radiopurity was determined by autoradiography of two-dimensional thin-layer chromatograms of the gangliosides. The method eliminates the need for extensive dialysis or repeated methanol evaporations to remove borate thus reducing time and the volume of labeled waste.