Relationship between zone length and step height in isotachophoresis

The relationship between response factor (RF) and specific zone resistance at 25°C (SZR25) in isotachophoresis was evaluated and a linear relationship between RF and SZR25 values could be established for strong ionic components. Working at a constant electric current, the RF value is proportional to the zone length (seconds) per mole of component. Because the SZR25 values are linearly related to the step heights in the isotachopherograms, the zone lengths per mole of sample component must be linearly related to the step heights of the sample components. If this relationship is measured for a standard mixture with an equimolar composition, all other unknown sample components can be quantified from the step heights in a single experiment. This principle was verified experimentally for several anionic and cationic leading electrolyte systems at different pH values.