N,N,N',N'-TETRAMETHYL-1,3-BUTANEDIAMINE AS EFFECTIVE RUNNING ELECTROLYTE ADDITIVE FOR EFFICIENT ELECTROPHORETIC SEPARATION OF BASIC-PROTEINS IN BARE FUSED-SILICA CAPILLARIES

The effect of N,N',N',N'-tetramethyl-1,3-butanediamine (TMBD) in the r unning electrolyte on the electroosmotic flow and the migration behavi or of four standard basic proteins in bare fused-silica capillaries wa s examined at pH 4.0, 5.5, and 6.5. Depending on the electrolyte pH an d additive concentration the electroosmotic flow was either cathodic o r anodic. A similar Langmuirian-type dependence of the electroosmotic flow on the concentration of TMBD in the running electrolyte was found at the three experimented pH values, which may be indicative of the s pecific adsorption of the additive in the immobilized region of the el ectric double layer at the interface between the capillary wall and th e electrolyte solution. Electrophoretic separations of the four standa rd basic proteins performed at the three above pH values, showed well- resolved, efficient and symmetric peaks, demonstrating the utility of this additive for protein electrophoresis in bare fused-silica capilla ries. The variations in separation efficiency, peak capacity, resoluti on and reproducibility of migration times as a function of the additiv e concentration at pH 6.5 were also examined.