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This paper shows the use of three-way data analysis methods to improve resolution and quantification in poorly separated peaks from capillary zone electrophoresis (CZE). Second-order data (data matrices) obtained with a diode array detector (DAD) are analyzed. There is a large overlap in the electrophoretic time domain and the data do not have a strict trilinear structure. These shortcomings might hinder the mathematical resolution. However, three-way methods allow the pure electrophoretic profiles of the analytes to be recovered in an unknown mixture, even in the presence of uncalibrated interferences. Furthermore, the analyte can be quantified in unknown mixtures with reasonable accuracy using pure standards. As an example, ebrotidine metabolites were chosen to test the method.

The efficiency and the reproducibility of different solid-phase adsorbents such as C18 cartridges, C18 and poly(styrene-divinylbenzene) (PS-DVB) membrane extraction disks were evaluated for the extraction of phenols from water at μg 1−1 concentration levels. Liquid chromatography with electrochemical detection (LC-ED) was used for the analysis of the organic extracts. A phosphate buffer-acetonitrile-methanol mixture as mobile phase and coulometric detection at + 750 mV were used. High recoveries (70–98%) and good reproducibility (relative standard deviation between 3 and 12%) were obtained using PS-DVB disks, which can be recommended for the enrichment of samples with low concentration of phenols (0.5 μg 1−1). For more concentrated samples (10 μg 1−1), the use of C18 cartridges was preferred because smaller solvent and sample volumes were used and the analysis time was reduced.