Sample diluent ionic strength, pH, organic solvent composition and viscosity can all have a significant impact on the performance of CE separation. It is, therefore, essential that the choice of solvent is optimized during method development. The optimized diluent should be fully specified in the method and used consistently in method validation and all subsequent applications of the method.

Accurate preparation and correct selection of buffers is essential to obtain reproducible and consistent results in capillary electrophoresis (CE). A number of factors should be considered in buffer optimization, including the pKa of the buffering ion and the analyte as well as the molarity of the acid or base used in the adjusting procedure. Accurate recording of the precise reagents used and the procedures performed is necessary to prepare buffers consistently. "Poor reproducibility of results and poor quantitative precision will be attainable in CE assays without significant attention being paid to the preparation of buffers used."

The authors describe how this free downloadable software calculates and displays CZE separations after the user has entered sample and operations parameters. The underlying principles and mathematical basis are explained.

In this article, the authors demonstrate the use of PFACE and two modifications to the technique: flow-through PFACE and multiple-step ligand injection to examine the binding of D-Ala-D-Ala terminus peptides to vancomycin from Streptomyces orientalis and arylsulphonamides to carbonic anhydrase B.

Guest author, Paul Cancalon, describes the role of capillary electrophoresis for the analysis of vitamins in citrus fruit juices. The separation is rapid with up to 30 citrus juice compounds capable of being separated in 20 min.

The authors provide an introductory description of MEEKC and highlight some of its applications. They demonstrate the separation possibilities offered by the technique for the analysis of pharmaceutical and non-pharmaceutical solutes.

This instalment explains why the use of internal standards improves the quantitative performance of CE...

The use of CE in three separate pharmaceutical companies is demonstrated as a successful technique for routine analysis...

The key features for method validation of small molecules using CE within the pharmaceutical industry are discussed...