Development of a confined wall-jet flow-through cell for simultaneous electrochemical and surface plasmon resonance applications

A flow-through cell of the confined wall-jet type for electrochemical surface plasmon resonance (ESPR) applications has been developed. The geometrical cell volume of the electrochemical (EC) detection is adjusted to the surface plasmon resonance (SPR) cell volume by reducing the electrode diameter. An electrode diameter of 3 mm gives the best similarity of the SPR and EC responses, using hexacyanoferrate(II) in a flow-injection analysis (FIA) setup. Further hydrodynamic characterization is done by continuous-flow analysis. The dependence of the limiting Faradaic current on the volume flow rate (φv) and the spacing (b) between working and auxiliary electrode have been determined. The exponents found for φv are in the range from 0.29 to 0.35 and for b in the range from −0.37 to −0.57 for typical flows (10–1000 μl min−1) and spacings (0.13–0.50 mm), respectively. inary results of an impedimetric/liposome-enhanced SPR immunosensor for interferon-γ (INF-γ), based on an acetylcysteine self-assembled monolayer, show the characteristics and applicability of this new flow-through cell for ESPR research in a FIA setup.