AGAROSE-GEL ELECTROPHORESIS OF POLYELECTROLYTES

Agarose gel electrophoresis of synthetic polyelectrolytes, sodium polystyrene sulphonate (NaPSS), poly(acrylic acid) sodium salts (Na-PA) and carboxymethyl cellulose sodium salts (CMC) was studied. Using NaPSSs which have narrow molecular weight distribution, depending on the relative dimensions of radii of gyration of polyions, Rg, and pore size in the gel, a, it was found that the electrophoretic migration mode is separated into three regimes, namely (1) Ogston (Rg≤a), (2) reptation without stretching (Rg>a) and (3) reptation with stretching, (Rg>>a). These findings are quite similar to the agarose gel electrophoresis of DNA first oserved by Slater and Noolandi. Using Na-PSS as standard samples, it was found that, in the regime of reptation without stretching, the friction coefficient f of a monomeric unit is proportional to the cube root of the molar volume of a monomer unit of Na-PA. For measurement of molecular weight of polyions with unknown molecular weight by gel electrophoresis, in the Ogston regime correction for the observed mobility is unnecessary if we use Na-PSS as a standard. However, in the regime (2), mobility should be corrected by evaluating the f of unknown polyions. © 1990 The Society of Polymer Science, Japan.