Dependence of the mobilities and mobility ratios observed for charge variants of the synthetic copolymers on: (A) and (C), the fractional charge of the copolymer; and (B) and (D), the logarithm of the fractional charge of the copolymer. The symbols in all panels correspond to: (●), partially hydrolyzed polyacrylamides; (o,△), polyacrylamide/Amps copolymers; and (▽), polystyrene sulfonates (see Table 1). The straight lines in (B) connect the mobilities of the charge variants of each copolymer and are meant to guide the eye. The straight line in (D) was drawn by linear regression; r2 = 0.976.