Time-resolved potentiometry on dual interface of two immiscible electrolyte solutions (ITIES): Step towards qualitative potentiometric analysis

Abstract The time-resolved potentiometry on dual interface of two immiscible electrolyte solutions (dual ITIES) combines redox- and phase transfer-driven potential response into a single protocol, which gains a compound-specific‚ finger-print’ character: The potential transient envelope was found to show pattern specific to molecules/ions appearing at the interface. The model system is represented by water/ o –dichlorobenzene/water dual interface with aqueous stationary (reference) and mobile (sample-carrying) phase with ternary amine salt as a phase transfer agent and alternatively, phthalocyanine-based redox mediator is added to o-dichlorobenzene phase. This potentiometric system shows biomimetic features with the selectivity simply modifiable just by varying composition of liquid phase. The transient potential response was found to correlate specifically with particular composition of sample brought by mobile phase and allows recognizing redox compounds, pH and different ions without a need of specific ion selective electrode.