In situ SERS spectroelectrochemical analysis of antioxidants deposited on copper substrates: What is the effect of applied potential on sorption behavior?

The detection of p-coumaric acid and ferulic acid using a combined in situ electrochemical and surface-enhanced Raman scattering spectroscopic technique in specially made electrode cell is described. New in situ spectroelectrochemical cell was designed as the three-electrode arrangement connected via positioning device to fiber-optic probe of Raman spectrometer Dimension P2 (excitation wavelength 785 nm). In situ SERS spectra of p-coumaric acid and ferulic acid were recorded at varying applied negative potentials to copper substrates. The spectral intensities and shapes of bands as well as spatial orientation of molecules on the surface depend significantly on varying values of the applied electrode potential. The change of electrode potential influences analyte adsorption/desorption behavior on the surface of copper substrates, affecting the reversibility of the whole process and overall spectral enhancement level. Principal component analysis is used to distinguish several stages of spectral variations on potential changes.

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► In situ spectroelectrochemical cell with easy changeable SERS-active electrode.
► Reversible adsorption of coumaric and ferulic acid on copper substrates.
► An electrode potential change influence on analyte adsorption/desorption behavior.
► PCA elucidation of spectral patterns variations in dependence on potential changes.