ELECTROPHEROGRAMS IN CAPILLARY-ZONE-ELECTROPHORESIS PLOTTED AS A FUNCTION OF THE QUANTITY OF ELECTRIC CHARGE

We have plotted electropherograms in capillary zone electrophoresis (C ZE) as a function of the quantity of electric charge ce, in order to e liminate the dependency of the analyte peak areas, as well as that of the migration times, upon both the capillary temperature and the appli ed voltage. The procedure is based on an idea of a migration index (MI ) and an adjusted migration index (AMI) which were originally proposed by Lee and Yeung. The value of Q is measured accurately and calculate d easily because it is given by a product of the electrophoretic curre nt and the migration times, where the index MI is derived by dividing the value of Q by the effective volume of the capillary. By calculatin g the CZE peak area from the plotted electropherogram, improvement in precision in quantitative analysis is expected. Concerning AMI, carefu l treatment is required in its application to analyte peaks whose migr ation time is close to that of the neutral marker. Experimental data a nd discussions concerning the migration indices are presented. (C) 199 8 Elsevier Science B.V. All rights reserved.