1998 W.A.E. McBryde Medal Lecture: Searching for the Holy Grail in analytical separations

Abstract

This paper describes the chemistry presented during the W.A.E. McBryde Medal address given at the 81st Chemistry in Canada Conference held in Whistler. The narrative chronicles our Quest to perform isotopic separations in the solution phase using as our Excalibur, capillary zone electrophoresis. The narrative takes you through the highs of our early success in separating 35Cl- and 37Cl-. This separation was achieved by adjusting the electroosmotic flow to be equal in magnitude but opposite in direction to the chloride mobility. The narrative then takes you through the dark days, when we could not extend the isotopic separations to cationic species or even explain why there was an isotopic effect on mobility. Since those dark days, we have made numerous discoveries that have aided our Quest. Firstly, the development of mixed surfactant wall coating procedures yielded control of the reversed electroosmotic flow. This control enabled us to perform isotopic separations of systems such as 15N-/14N-aniline and 15NH4+/14NH4+. In terms of understanding electrophoretic mobility, we demonstrate the importance of dielectric friction to mobility. Further, the effect of ionic strength in capillary zone electrophoresis is explained using the Pitts treatment, which is analogous to the extended Debye-Hückel equation for ionic activity. So, have we completed our Quest? Read on.Key words: capillary zone electrophoresis, isotopic, electroosmotic flow, mobility modeling, ionic strength.