Electrochemistry and SPR (ESPR) allows the seamless integration of SPR (surface plasmon resonance) with electrochemical measurements. When combined, researchers can look at both optical and electrochemical properties of interfaces concurrently. Surface effects that can be studied include: thin film formation (SAM formation), adsorption/desorption, polymer formation, redox initiated conformation changes and trace metals. Since SPR is sensitive to both the adsorbed layer on the gold electrode and to the dielectric properties of the solution phase, electrochemically modulated diffusion layers can be detected.

Reichert’s ESPR flow cell can be used to study a variety of Surface Chemistry related projects. For ESPR experiments, you can combine the highly sensitive Reichert SR7500 SPR instrument with the excellent low current performance of a PAR Versastat 4 Potentiostat (or use your own potentiostat) to obtain high quality ESPR data.

Reichert’s SR7500DC is used together with a PAR Versastat 4 Potentiostat to analyze the electropolymerization of aniline on a gold slide. The SPR data shows the increase in angle and response as polyaniline is added to the gold surface (10 cycles repeated 4 times after aniline is injected). The cyclic staircase voltammetry scans show the buildup of polymer layers on the surface. We chose the cyclic staircase waveform since it is a pulse technique which allows for sampling near the end of the potential step where charging current is minimized versus sample current.

         Increase in Current Corresponds to Increasing Scan Number

                                                                                               

The SPR response reaches a maxium after about 4 scan cycles of 10 scans each. The increase in Angle (inset) corresponds to a uRIU increase of about 20,000 as polyaniline is formed on the surface. A characteristic blue color can be seen on the slide surface when removed.
                                                                                                                    
For more information on Reichert's ESPR options, please visit http://www.reichertspr.com/technology/spr-electrochemistry/ or Contact Us.