Factors Influencing Performance

Abstract

Electrophoresis in capillaries has already demonstrated its great value as an analytical tool in pharmaceutical analysis, biochemistry, etc., as witnessed by an increasing stream of publications. The resolution even of complicated mixtures obtained by CE often excels that of chromatographic techniques. The extremely high resolving power of CE certainly originates from the fact that most dispersive effects can be kept well under control in modern instrumentation. Nevertheless: “Felix qui potuit rerum cognoscere causas” (Vergil), or in our words: it is eminently important to understand these effects and to estimate their influences on the separation. This is the objective of the following chapter, where we discuss the most important dispersive effects and demonstrate possibilities to minimize them. In addition, influences of operational conditions like field strength, capillary dimensions and temperature are pointed out. Furthermore, we show how selectivity can be manipulated by the choice of buffer electrolyte. Here, the most effective parameters such as pH, ionic strength, buffer composition, complex formation and organic modifiers are discussed.