Capillary electrophoresis in sieving matrices: selectivity per base, mobility slope, and inflection slope

We compare the migration behavior of DNA sequencing fragments in hydroxyethyl cellulose (HEC) to the theoretical model of migration in the reptation mode. Good agreement was found for the mobility curve. We derived empirical equations for the relationship between selectivity per base and sieving matrix concentration and between the mobility slope and matrix concentration. We propose the inflection slope, i.e., the slope of the log-log mobility curve at its inflection point, as the quantitative parameter of sieving performance.