Investigations of the Potential-Dependent Structure of Phenylalanine on the Glassy Carbon Electrode by Infrared−Visible Sum Frequency Generation

Abstract

We investigated the structure of adsorbed L-phenylalanine (Phe) on the glassy carbon electrode (GCE) as a function of electrode potential using infrared-visible sum frequency generation (SFG) vibrational spectroscopy. Experiments using partially deuterated Phe confirmed that SFG signal originates from the CH stretch modes of the methylene group (CH 2 ) in Phe. Quantitative analysis of SFG spectra revealed that Phe molecules adopt a conformation in which the dipole contribution of the asymmetric mode of the methylene group becomes greater than the symmetric mode with respect to the surface normal at highly positive electrode potential.

The reduction of 4-nitrobenzene diazonium electrografted layer: An electrochemical study coupled to in situ sum-frequency generation spectroscopy

“…This latter is an intrinsic surface vibrational spectroscopy which exhibits extreme sensitivity towards the electrochemical interface and allows information to be obtained upon various systems such as supported catalysts [47], nanoparticles [48] or thin films adsorbed onto electrode surface [49]. Until now, only the group of Somorjai has studied phenylalanine adsorption and orientation on a GC electrode as a function of the applied potential in the CH stretching IR spectral range [50,51]. Here, the signal corresponding to the symmetric stretch of the NO 2 groups was observed and its decay was followed in situ during the electrolysis process.…”

In vitro observation of dynamic ordering processes in the extracellular matrix of living, adherent cells

“…[29][30][31][32][33][34][35][36][37][38][39][40] In particular, this technique has been applied to the in situ investigation of biomolecules, including peptides, [41][42][43][44][45][46][47][48][49][50][51][52] proteins, and DNA. [75][76][77][78][79] Previous work from our lab has demonstrated the ability of SFG spectroscopy to detect substrate modifications through a layer of adherent, fixed cells 80 and through living, nonadherent cells.…”

The evolution of model catalytic systems; studies of structure, bonding and dynamics from single crystal metal surfaces to nanoparticles, and from low pressure (<10−3Torr) to high pressure (>10−3Torr) to liquid interfaces

“…Fig.9shows the orientation change of acetonitrile as a function of potential of the platinum electrode. Additionally, the potential-dependent interfacial structure of the amino acid phenylalanine was examined at the glassy carbon electrode/electrolyte interface 69. These attempts at understanding the potential-dependent structure of molecules at electrified interfaces were extended to the monitoring of a reversibly switching surface in 2003 70.…”