Abstract
An interface of two immiscible electrolyte solutions (dual ITIES) was investigated for application as a biomimetic sensor for potentiometric flow analysis. The dual ITIES was formed by a water/ortho-dichlorobenzene/water interface in free-standing and nanoporous membrane-supported arrangements.
One aqueous phase served as the mobile and second aqueous phase as the stationary phase. The nonaqueous (ortho-dichlorbenzene) phase contained dissolved phthalocyanine as a redox mediator, whereas tetrabutylammonium perchlorate acted as a phase transfer agent.
The sensing mechanism utilized ambient oxygen for regeneration of the redox mediator; the sensor thus operates under air conditions where oxygen serves to partially establish the equilibrium interface potential. The free-standing and nanoporous membrane-supported arrangements provided fast and reproducible response for flow analysis with sulfide serving as a model analyte.
Good stability, fast recovery, and high resistance to saturation were found. The signal-to-noise ratio was discussed with respect to electrolyte concentration and gaseous bubbles trapped on the membrane.