Methods Development in Capillary Electrophoresis with Automated Peak Tracking by Chemometric Analysis of Diode Array Detection Data

Abstract

Developing methods for capillary electrophoresis is complicated by the complex array of interacting variables that affect resolution. Optimizing a separation is, therefore, time-consuming. This process can be minimized and simplified if the individual sample components can be tracked through a minimal structured experimental set. We have adapted an HPLC methods development system, Unicam Diamond Optimization Software, for this purpose. An experimental plane of ten different conditions is executed, and the separations are monitored with a diode array detector. Each three-dimensional data file is subjected to Principal Component Analysis and Iterative Target Transform Factor Analysis to test the spectral homogeneity of each peak and to deconvolute comigrations. The resulting pure spectra are used to track the individual sample components across the experimental plane. In this way, a migration model is calculated for each analyte, and, in turn, a resolution map is constructed. The optimal CE separation is obtained with a minimal number of experiments and without prior knowledge of the sample or the use of standards. This approach is illustrated and tested with over-the-counter pharmaceutical preparations.