Potentiometric Detection of Organic Ionics in Separation Methods: a Critical Evaluation

Ionically conducting rubber phase coatings are suited for use in the mobile phase conditions of HPLC (gradient elution, organic mobile phase components), and for low flow-rate applications such as used in capillary electrophoresis (CE). Especially organic ionic analytes of industrial-, biotech- and pharmaceutical environments are the potential fields of application. Much work remains to be done to understand why multiply charged molecules perform much better than expected from models used for small polyionic (mostly metal ion) subjects. The present work concentrates on phenomena that at first sight could be classified as deviations from Nernst and Nicolskii-Eisenmann type behaviour. The non-equilibrium conditions in hydrodynamic methods, lack of experimental data and lack of in sight into the process generating potential are shown as the cause of mis interpretations when using this young and promising technique.