REPRESENTING PRIMARY ELECTROPHORETIC DATA IN THE 1 TIME DOMAIN - COMPARISON TO REPRESENTATIONS IN THE TIME-DOMAIN/

A plot of absorbance vs 1/time (the ''1/time domain'') is a more usefu l representation of the primary data in capillary electrophoresis than traditional plots of absorbance vs time (the ''time domain'') in a wi de set of circumstances, especially when comparing electropherograms i n which the rate of electroosmotic flow is not precisely the same, The quantity that is of fundamental interest in capillary electrophoresis (CE) is the electrophoretic mobility of an analyte, The electrophoret ic mobility of a species is nonlinearly proportional to time and, ther efore, not linearly represented in the time domain: that is, the dista nce between two peaks along the time axis is not linearly related to t he difference in their electrophoretic mobilities, In contrast, the el ectrophoretic mobility is linearly proportional to 1/time, and the dis tance between two peaks along the 1/time axis is linearly related to t he difference in electrophoretic mobilities. Plots in the 1/time domai n are similar to the familiar plots in the time domain (each analyte i s represented by a peak, and the order of peaks corresponds to the ord er in which these analytes reach the detector), but the spacing betwee n the peaks corresponds linearly to differences in mobility, This arti cle derives this useful, visually appealing, and broadly applicable pl otting strategy and illustrates common situations in which these plots are more useful than plots in the time domain.