Sieving matrices in capillary electrophoresis: Inflection slope and doublereciprocal plot

We propose the use of a double reciprocal plot of the inflection slope and the concentration of a sieving polymer to compare sieving properties of pol ymers regardless of their concentration and to permit selection of appropri ate sieving materials. Using this plot, the lines extrapolating the experim ental values intersect the ordinate at the value corresponding to the infle ction slope at the infinite concentration of the sieving polymer and the ab scissa at the value characteristic for the given polymer. The latter corres ponds to the polymer concentration at which the inflection slope equals hal f the inflection slope at an infinite polymer concentration. It is inversel y proportional to intrinsic viscosity and this makes intrinsic viscosity an important physicochemical constant suitable for selection of new potent si eving polymers.