Quantitative analysis in capillary electrophoresis: transformation of raw electropherograms into continuous distributions.

Quantitative analysis in capillary electrophoresis based on time-scale electropherograms generally uses time-corrected peak areas to account for the differences in apparent velocities between solutes. However, it could be convenient and much more relevant to change the time-scale electropherograms into mass relative distribution of the effective mobility or any other characteristic parameter (molar mass, chemical composition, charge density, ...). In this study, the theoretical background required to perform the variable change on the electropherogram was developed with an emphasis on the fact that both x and y axes should be changed when the time scale electropherograms are modified to get the distributions. Applications to the characterization of polymers and copolymers by different modes of capillary electrophoresis (CE) are presented, including the molar mass distribution of poly-L-lysine oligomers by capillary gel electrophoresis (CGE), molar mass distribution of end-charged poly-l-alanine by free solution CE, molar mass distribution of evenly charged polyelectrolytes by CGE, and charge density distribution of variously charged polyelectrolytes by free solution CE.