Electrochemical SERS and its Application in Analytical, Biophysical and Life Science

Abstract

Raman spectroscopy, as a vibrational spectroscopy, can record fingerprint spectra from electrodes and provide much insight into a variety of surface and interfacial processes at the molecular level: for example, qualitatively determining surface bonding, conformation and orientation. Raman spectroscopy invariably uses lasers from the ultraviolet (UV) to the near infrared (NIR). More importantly, the technique can be applied in situ to investigate solid–liquid, solid–gas and solid–solid interfaces of both fundamental and practical importance. The technique can be used flexibly to study porous electrode materials of high surface area, to which many surface techniques are not applicable. Therefore, Raman spectroscopy is among the most promising methods for use in electrochemistry. The major disadvantage of Raman spectroscopy is its very low detection sensitivity. However, surface-enhancedRaman scattering (SERS) can improve the sensitivity significantly by several orders of magnitude for roughened surfaces of many metals including noble and transition metals. This chapter will first introduce some fundamental background and features of electrochemical surface-enhanced Raman scattering (EC-SERS), followed by a detailed description of the experimental setup for electrochemical Raman spectroscopy and preparation of SERS substrates. The emphasis will be on how to obtain reliable information of very sensitive bio-related systems. Some examples, varying from amodelmolecule of benzene to real biomolecules, such as dopamine, NADH, DNA and cytochrome c (cyt c), will be shown to demonstrate how to apply EC-SERS for bio-related application. Finally, prospects and further developments of EC-SERS application in bio-related systems will be discussed.